Showing papers in "American Journal of Clinical Pathology in 2004"

Enigmatic Kikuchi-Fujimoto disease: a comprehensive review.

Abstract: To determine the clinicopathologic significance of Kikuchi-Fujimoto disease (KFD) and review the literature on this condition, we conducted a MEDLINE search of English-language articles published between 1972 and December 2003. KFD has a worldwide distribution, and Asiatic people have a higher prevalence. Its pathogenesis remains controversial. Patients are young and seek care because of acute tender, cervical lymphadenopathy and low-grade fever. Histologic findings include paracortical areas of coagulative necrosis with abundant karyorrhectic debris. Karyorrhectic foci consist of various types of histiocytes, plasmacytoid monocytes, immunoblasts, and small and large lymphocytes. There is an abundance of T cells with predominance of CD8+ over CD4+ T cells. Differential diagnosis includes lymphoma, lymphadenitis associated with systemic lupus erythematosus, and even adenocarcinoma. KFD is an uncommon, self-limited, and perhaps underdiagnosed process with an excellent prognosis. Accurate clinicopathologic recognition is crucial, particularly because KFD can be mistaken for malignant lymphoma.

Flow cytometric immunophenotypic analysis of 306 cases of multiple myeloma.

Abstract: Bone marrow aspirates from 306 patients with multiple myeloma were analyzed by flow cytometric immunophenotyping. The plasma cells (PCs) were identified by their characteristic light scatter distribution and reactivity patterns to CD138, CD38, and CD45. Monoclonality was confirmed by immunoglobulin light chain analysis. The immunophenotypic profile of the PCs was determined with a panel of antibodies. Moderate to bright expression of CD56, CD117, CD20, CD45, and CD52 was detected in 71.7%, 17.8%, 9.3%, 8.8%, and 5.2% of cases, respectively. These antigens were expressed by a distinct subpopulation of the PCs in 6.3%, 2.2%, 3.7%, 2.9%, and 2.6% of additional cases. CD19 was negative in more than 99% of cases. The combination of CD38 and CD138 was superior to CD38 alone for identifying CD45+ myeloma and separating CD20+ myeloma from B-cell lymphoma. PC immunophenotyping might be useful for detecting minimal residual disease in cases with aberrant antigen expression and for selection of therapeutic agents that have specific membrane targets.

CD163: a specific marker of macrophages in paraffin-embedded tissue samples.

Abstract: Paraffin-section immunohistochemical analysis was performed using a monoclonal antibody against CD163 to evaluate the antibody's usefulness in identifying cells of monocyte/macrophage lineage in normal and neoplastic conditions. Normal human tissue samples and samples from 211 hematopoietic disorders and 115 nonhematopoietic neoplasms were examined. The distribution of KP1 and PG-M1, monoclonal antibodies to the macrophage-associated CD68 antigen, also were evaluated for comparison. CD163 immunoreactivity was observed in resident macrophages of all normal tissue samples except splenic white pulp macrophages and germinal center tingible body macrophages. Among hematopoietic disorders and nonhematopoietic neoplasms, CD163 expression was restricted largely to cases of chronic myelomonocytic leukemia, histiocytic sarcoma, sinus histiocytosis with massive lymphadenopathy, and littoral cell angioma. Acute myeloid leukemias (AMLs) with monocytic differentiation were CD163- with the exception of 1 case of acute monoblastic leukemia. Most myeloid sarcomas also were CD163-. Compared with the CD68 antibodies, CD163 demonstrated greater specificity as a marker of disorders of monocyte/macrophage origin. However, immunohistochemical evaluation of CD163 expression does not seem to be a sensitive means of determining monocytic differentiation in AMLs in paraffin sections or establishing a diagnosis of myeloid sarcoma.

Gaucher cells demonstrate a distinct macrophage phenotype and resemble alternatively activated macrophages.

Abstract: Although the existence of anti-inflammatory alternatively activated macrophages (aamphi) has been accepted widely based on in vitro studies, their in vivo location, phenotype, and function still are debated. Gaucher disease (GD) is caused by a genetic deficiency in the lysosomal enzyme glucocerebrosidase and is characterized by accumulation of glycosphingolipids in so-called Gaucher cells (GCs). By using immunohistochemical analysis, we investigated whether this results in an aamphi phenotype. GCs are macrophage-like cells, expressing acid phosphatase, CD68, CD14, and HLA class II, but not CD11b, CD40, or dendritic cell markers. GCs show infrequent immunoreactivity for mannose receptor GCs did not express proinflammatory cytokines such as tumor necrosis factor alpha and monocyte chemoattractant protein 1, but did express the aamphi markers CD163, CCL18, and interleukin-1 receptor antagonist. Furthermore, CD36 and signal receptor protein alpha, involved in lipid uptake, also were observed on GCs. Thus, GCs represent a distinctive population of myeloid cells that resemble aamphi but differ from previously described in vitro aamphi.

CD138 (syndecan-1), a plasma cell marker immunohistochemical profile in hematopoietic and nonhematopoietic neoplasms.

Abstract: We evaluated the immunohistochemical profile and specificity of CD138 reactivity in 238 specimens from hematopoietic and nonhematopoietic neoplasms. In 91 bone marrow biopsies, CD138 reactivity was observed for nonneoplastic plasma cells, neoplastic plasma cells in multiple myeloma cases (43/43), and the plasmacytic component in lymphoplasmacytic lymphoma cases (4/4). Stromal reactivity was noted in 7 multiple myeloma cases. Of 9 bone marrow specimens involved by metastatic carcinoma, tumor cells were CD138+ in 5 cases; stromal reactivity was noted in 7 cases. Studies of 76 nodal and extranodal lymphomas (B-cell, 49; T-cell, 8; Hodgkin lymphoma, 19), 1 Langerhans cell histiocytosis, and 14 nonneoplastic lymph nodes revealed CD138 reactivity only for nonneoplastic plasma cells, the neoplastic cells of 2 large B-cell lymphomas (immunoblastic type, plasmacytoid features), and the clonal plasmacytic component of 3 of 3 extranodal and 1 nodal marginal zone lymphoma. Evaluation of 56 epithelial and nonepithelial tumors revealed CD138 positivity for neoplastic cells of carcinomas of various types (30/33), frequently with associated stromal reactivity, and for neoplasms of mesenchymal, melanocytic, and other tumor types (12/23). Within the hematopoietic system, CD138 is an excellent marker of plasmacytic differentiation. Based on its broad staining profile, CD138 reactivity for neoplastic cells is not a definitive marker for plasmacytic derivation, unless a hematolymphoid origin has been established.

Targeted therapies for cancer 2004.

Abstract: The regulatory agency approvals in the United States and Europe of imatinib mesylate (Gleevec) for patients with bcr/abl-positive chronic myelogenous leukemia, cetuximab (Erbitux) for patients with epidermal growth factor receptor overexpressing metastatic colorectal cancer, the antiangiogenesis agent bevacizumab (Avastin), and the proteasome inhibitor bortezomib (Velcade)—and the considerable public interest in new anticancer drugs that take advantage of specific genetic defects that render the malignant cells more likely to respond to specific treatment—are driving a new era of integrated diagnostics and therapeutics. The recent discovery of a drug response predicting activating mutation in the epidermal growth factor receptor gene for patients with non–small cell lung cancer treated with gefitinib (Iressa) has intensified this interest. In this review, the history of targeted anticancer therapies is highlighted, with focus on the development of molecular diagnostics for hematologic malignancies and the emergence of trastuzumab (Herceptin), an antibody-based targeted therapy for HER-2/neu overexpressing metastatic breast cancer. The potential of pharmacogenomic strategies and the use of high-density genomic microarrays to classify and select therapy for cancer are briefly considered. This review also considers the widely held view that, in the next 5 to 10 years, the clinical application of molecular diagnostics will further revolutionize the drug discovery and development process; customize the selection, dosing, route of administration of existing and new therapeutic agents; and truly personalize medical care for cancer patients. The regulatory approvals of trastuzumab (Herceptin), imatinib mesylate (Gleevec), and cetuximab (Erbitux) for patients with HER-2/neu overexpressing breast cancer, bcr/abl translocation–positive chronic myelogenous leukemia (CML), and epidermal growth factor receptor (EGFR)-overexpressing colorectal cancer, respectively, have headlined the considerable public interest in new targeted anticancer drugs. 1-3 In addition, a large number of new targeted therapies for patients with cancer, including additional small-molecule tyrosine kinase inhibitors, antisense messenger RNA inhibitors, and antibodies are in both early and late stages of clinical development. Many scientists, clinicians, and pharmaceutical company executives believe that during the next 5 to 10 years, the integration of molecular oncology and molecular diagnostics will further revolutionize oncology drug discovery and development; customize the selection, dosing, route of administration of previously approved traditional agents and new therapeutics in clinical trials; and truly personalize medical care for patients with cancer. 4-7

Enigmatic Kikuchi-Fujimoto Disease

Abstract: To determine the clinicopathologic significance of Kikuchi-Fujimoto disease (KFD) and review the literature on this condition, we conducted a MEDLINE search of English-language articles published between 1972 and December 2003. KFD has a worldwide distribution, and Asiatic people have a higher prevalence. Its pathogenesis remains controversial. Patients are young and seek care because of acute tender, cervical lymphadenopathy and low-grade fever. Histologic findings include paracortical areas of coagulative necrosis with abundant karyorrhectic debris. Karyorrhectic foci consist of various types of histiocytes, plasmacytoid monocytes, immunoblasts, and small and large lymphocytes. There is an abundance of T cells with predominance of CD8+ over CD4+ T cells. Differential diagnosis includes lymphoma, lymphadenitis associated with systemic lupus erythematosus, and even adenocarcinoma. KFD is an uncommon, self-limited, and perhaps underdiagnosed process with an excellent prognosis. Accurate clinicopathologic recognition is crucial, particularly because KFD can be mistaken for malignant lymphoma.

Haptoglobin phenotypes in health and disorders.

Abstract: Haptoglobin is a positive acute phase protein that binds free hemoglobin and removes it from the circulation to prevent kidney injury, and iron lossfollowing hemolysis Also, by bindingfree hemoglobin, haptoglobin functions as an antioxidant In addition, haptoglobin acts as a potent immunosuppressor of lymphocyte function and modulates the helper T-cell type 1 and type 2 (Th1/Th2) balance within the body Three major haptoglobin phenotypes are known to exist (Hp 1-1, Hp 2-1, and Hp 2-2) Hp 1-1 is biologically the most effective in binding free hemoglobin and suppressing inflammatory responses associated with free hemoglobin Hp 2-2 is biologically the least active, and Hp 2-1 is moderately active The possible association of allelic polymorphism of haptoglobin with various pathologic conditions such as coronary artery disease has been studied This article reviews the known functions of haptoglobin and the present understanding of a possible association of haptoglobin phenotypes with pathogenesis of a number of human disorders

Differential Expression of MUC1, MUC2, and MUC5AC in Carcinomas of Various Sites

Abstract: We studied immunohistochemical expression of MUC1, MUC2, and MUC5AC in 194 carcinomas of different primary sites to determine whether differential expression patterns could be used to distinguish different carcinomas. MUC1 was expressed by most (except adrenocortical and hepatocellular carcinomas). MUC2 was expressed infrequently (positive immunoreactivity primarily in tumors of gastrointestinal origin). MUC5AC was expressed by most pancreatic ductal and endocervical adenocarcinomas and a variable number of tumors of the gastrointestinal tract. A MUC1+/MUC2–/MUC5AC– immunophenotype was observed in most breast, lung, kidney, bladder, endometrial, and ovarian carcinomas; MUC1+/MUC2–/MUC5AC+ was characteristic of pancreatic ductal adenocarcinomas and cholangiocarcinomas. Adrenocortical and hepatocellular carcinomas were negative for all mucins. Carcinomas of gastrointestinal origin exhibited variable expression of each mucin examined and no consistent immunoreactivity pattern. Many carcinomas can exhibit distinct MUC1, MUC2, and MUC5AC expression patterns, which might be valuable diagnostically in specific settings (eg, distinguishing cholangiocarcinoma from hepatocellular carcinoma or renal from adrenocortical carcinoma). However, the overlapping and heterogeneous patterns of MUC1, MUC2, and MUC5AC expression observed in many tumors, particularly those of gastrointestinal origin, preclude use of these markers in the routine immunohistochemical assessment of carcinomas of an unknown primary site.

Differential expression of MUC1, MUC2, and MUC5AC in carcinomas of various sites: an immunohistochemical study.

Abstract: We studied immunohistochemical expression of MUC1, MUC2, and MUC5AC in 194 carcinomas of different primary sites to determine whether differential expression patterns could be used to distinguish different carcinomas. MUC1 was expressed by most (except

CD138 (Syndecan-1), a Plasma Cell Marker

Abstract: We evaluated the immunohistochemical profile and specificity of CD138 reactivity in 238 specimens from hematopoietic and nonhematopoietic neoplasms. In 91 bone marrow biopsies, CD138 reactivity was observed for nonneoplastic plasma cells, neoplastic plasma cells in multiple myeloma cases (43/43), and the plasmacytic component in lymphoplasmacytic lymphoma cases (4/4). Stromal reactivity was noted in 7 multiple myeloma cases. Of 9 bone marrow specimens involved by metastatic carcinoma, tumor cells were CD138+ in 5 cases; stromal reactivity was noted in 7 cases. Studies of 76 nodal and extranodal lymphomas (B-cell, 49; T-cell, 8; Hodgkin lymphoma, 19), 1 Langerhans cell histiocytosis, and 14 nonneoplastic lymph nodes revealed CD138 reactivity only for nonneoplastic plasma cells, the neoplastic cells of 2 large B-cell lymphomas (immunoblastic type, plasmacytoid features), and the clonal plasmacytic component of 3 of 3 extranodal and 1 nodal marginal zone lymphoma. Evaluation of 56 epithelial and nonepithelial tumors revealed CD138 positivity for neoplastic cells of carcinomas of various types (30/33), frequently with associated stromal reactivity, and for neoplasms of mesenchymal, melanocytic, and other tumor types (12/23). Within the hematopoietic system, CD138 is an excellent marker of plasmacytic differentiation. Based on its broad staining profile, CD138 reactivity for neoplastic cells is not a definitive marker for plasmacytic derivation, unless a hematolymphoid origin has been established.

Claudin 4 protein expression in primary and metastatic pancreatic cancer: support for use as a therapeutic target.

Abstract: We performed a comprehensive immunohistochemical evaluation of claudin 4 protein expression in paraffin-embedded tissue samples from 72 patients with primary infiltrating pancreatic cancer, 38 patients with metastatic pancreatic cancer, and a panel of normal control tissue samples from various organs. In 11 samples of primary infiltrating pancreatic cancer, foci of pancreatic intraepithelial neoplasia (PanIN) were present and also were analyzed for claudin 4 protein expression. Intense positive claudin 4 immunolabeling was noted within virtually all primary (71/72 [99%]) and metastatic (49/49 [100%]) pancreatic cancer tissue samples analyzed and in 10 of 11 samples of PanIN. In all cases, immunolabeling was noted in a membranous distribution. Claudin 4 protein also was detectable in normal breast, prostate, bladder, and gastrointestinal mucosa, although expression was substantially less intense than that seen in pancreatic cancer tissue samples. Our findings support the use of claudin 4 as a target for novel therapeutics or radioimaging of infiltrating pancreatic cancer. Furthermore, the finding of claudin 4 overexpression within pancreatic intraepithelial neoplasia, the precursor lesion of pancreatic cancer, suggests a potential benefit of imaging claudin 4 before the development of an invasive carcinoma.

Endoscopic ultrasound-guided fine-needle aspiration cytology diagnosis of solid-pseudopapillary tumor of the pancreas: a rare neoplasm of elusive origin but characteristic cytomorphologic features.

Abstract: Clinical histories, endoscopic ultrasound (EUS)guided fine-needle aspiration (FNA) material, and immunohistochemical stains performed on cell block samples of 6 solid-pseudopapillary tumors of the pancreas (SPTPs) were reviewed in the cases of 5 females (13-58 years) and 1 man (57 years); all had abdominal pain. Preliminary cytologic diagnoses at endoscopy included 1 SPTP, 2 low-grade neoplasms, and 3 pancreatic endocrine tumors. Variable numbers of branching fragments with central capillaries and myxoid stroma were seen in the smears of 5 of 6 cases but were more apparent in the cell block material of all cases. The cells had bland nuclear features and rare grooves. Extensive necrosis was noted in 1 case and rare mitotic figures in 1. SPTPs showed strong cellular immunoreactivity for vimentin and focal weak keratin reactivity. Neuron-specific enolase, α 1 -antitrypsin, and α 1 -antichymotrypsin stains performed in 2 cases were strongly positive. Subsequent surgical resection confirmed all diagnoses. EUS-guided FNA diagnosis of SPTP is accurate. The characteristic branching papillae with myxoid stroma are best seen in cell block slides. Clinical setting, cytomorphologic features, and immunostains of the cell block help distinguish SPTP from pancreatic endocrine tumors, acinar cell carcinoma, and papillary mucinous carcinoma. Solid-pseudopapillary tumor of the pancreas (SPTP) is a rare neoplasm of uncertain origin, often-indolent biologic behavior, and distinctive pathologic features. It constitutes approximately 1% of pancreatic neoplasms and 3% of cystic lesions of the pancreas. 1-3

Invasive micropapillary carcinoma of the breast: clinicopathologic study of 62 cases of a poorly recognized variant with highly aggressive behavior.

Abstract: We report 62 cases of invasive micropapillary carcinoma of the breast characterized by delicate pseudopapillary structures lacking a fibrovascular core and by tubuloalveolar structures freely floating in clear, empty spaces. All patients but 1 were women (median age, 57 years; range, 25-89 years). Tumor size ranged from 0.7 to 10 cm (median, 2.8 cm); 54 (87%) were grade 3. Psammoma bodies were identified in 29 (47%). Focal to massive lymphatic permeation was present in 39 (63%). Architectural features were retained in the node metastases, dermal lymphatics, and recurrences. Fifty-six patients (90%) had metastatic axillary nodes: 18 tumors were estrogen receptor–positive (32%); 11 were progesterone receptor–positive (20%); HER2/neu was overexpressed in 53 (95%) and p53 in 39 (70%). A peculiar immunoreactivity for MUC1 limited to the cytoplasmic membrane oriented toward the stroma and an absence of immunoreactivity for E-cadherin in the same side of the cytoplasmic membrane indicated inversion of cell polarization and a disturbance in the cell adhesion molecules. Of 41 patients with available follow-up, 29 (71%) had local recurrence (mean, 30 months) and 20 (49%) died of disease. These results underscore the aggressive behavior and poor prognosis of this breast carcinoma variant. Aggressive preoperative neoadjuvant chemotherapy should be considered.

Immunohistochemical characterization of signet-ring cell carcinomas of the stomach, breast, and colon.

Abstract: We studied the immunophenotype of signet-ring cell carcinoma (SRCC) of the stomach (30 cases), breast (21 cases), and colon (9 cases) with the following expression patterns: (1) breast: consistent, MUC1 (21 [100%]), cytokeratin (CK) 7 (20 [95%]), estrogen receptor (ER; 17 [81%]); infrequent, E-cadherin (6 [29%]), MUC2, MUC5AC, CK20 (1 [5%] each); negative, CDX2 and hepatocyte paraffin 1 (Hep Par 1; 0 [0%] each); (2) gastric: frequent, CDX2 (27 [90%]) and Hep Par 1 (25 [83%]); variable, E-cadherin and CK20 (17 [57%] each), MUC2 and MUC5AC (15 [50%] each), MUC1 (5 [17%]); negative, ER (0 [0%]); and (3) colon: frequent, MUC2 (9 [100%]), CDX2 and MUC5AC (8 [89%] each); infrequent or negative, MUC1 (3 [33%]), Hep Par 1 (2 [22%]), ER (0 [0%]). Immunohistochemical staining distinguished breast from gastric SRCC (ER, MUC1, Hep Par 1, CDX2) and colon SRCC (ER, CDX2, MUC2, and MUC5AC). Gastric and colon SRCCs showed a similar staining pattern for antibodies tested except for Hep Par 1 and CDX2 (gastric, 83% Hep Par 1 positivity and heterogeneous, weak, patchy CDX2 nuclear staining; colon, 22% Hep Par 1 positivity and homogeneous, strong, diffuse CDX2 nuclear staining). About half of the cases of gastric SRCC expressed MUC2 and MUC5AC, whereas virtually all cases of colon SRCC expressed them.

Lowering the detection limits of HIV-1 viral load using real-time immuno-PCR for HIV-1 p24 antigen.

Abstract: Presently, the assay that attains maximal sensitivity and dynamic range of HIV-1 viral copy number (50 copies per milliliter) is nucleic acid amplification of HIV RNA in plasma. Enzyme-linked immunosorbent assay (ELISA) methods for quantification of HIV-1 p24 antigen have been relatively insensitive. In this report, we show data that indicate real-time immuno-polymerase chain reaction (IPCR), a combination of the ELISA and PCR techniques, is more sensitive for HIV-1 p24 antigen detection than other currently reported methods. When derived from an IPCR standard curve, a dose response was observed from patient samples with known viral loads diluted within a 3-log range (1.68-6,514 viral RNA copies per milliliter). IPCR detected 42% (22/52) of patient samples that had fewer than 50 viral RNA copies per milliliter by reverse transcriptase-PCR. IPCR shows the potential to become the most analytically sensitive test available for determination of HIV-1 viral load by the detection of HIV-1 p24 antigen.

HER-2 testing in breast cancer using immunohistochemical analysis and fluorescence in situ hybridization: a single-institution experience of 2,279 cases and comparison of dual-color and single-color scoring.

Abstract: We analyzed concordance between immunohistochemical analysis and fluorescence in situ hybridization (FISH) in HER-2 status and studied the effect of dual-color (D-FISH) vs single-color FISH (S-FISH) scoring on the assignment of tumors to amplified or nonamplified categories. The assays were performed on formalin-fixed, paraffin-embedded sections of 2,279 invasive breast carcinomas. Immunohistochemical results were interpreted as negative (0, 1+) or positive (2+, 3+). For FISH analyses, a ratio for HER-2/chromosome 17 of 2.0 or more (D-FISH) or an absolute HER-2 copy number per nucleus of more than 4.0 (S-FISH) were interpreted as positive gene amplification. We found 547 (24.0%) cases positive immunohistochemically, 326 (14.3%) by D-FISH, and 351 (15.4%) by S-FISH. Overall concordance in HER-2 status with immunohistochemical analysis was 87% for D-FISH and 86% for S-FISH. Excellent concordance was found among groups scored immunohistochemically as 0, 1+, and 3+ (with D-FISH, 97%; with S-FISH, 96%). The most discordant category was the group scored 2+ immunohistochemically, in which only a quarter of the 2+ tumors were FISH(+). D-FISH and S-FISH scoring results were discordant in 89 tumors (4%), of which 8 (9%) had 3+ immunohistochemical staining and none showed high-level HER-2 amplification. Among all FISH(+) tumors, 10% were negative by immunohistochemical analysis, and notably almost half (47%) showed borderline to low HER-2 amplification (D-FISH score, 2.0-3.9); the clinical significance of these findings warrants further investigation.

Papillomas and atypical papillomas in breast core needle biopsy specimens: risk of carcinoma in subsequent excision.

Abstract: We sought to define the risk associated with papillomas and atypical papillomas in breast core needle biopsy specimens from a series of approximately 8,500 biopsies performed during 8 years. From a total of 62 papillary lesions (including papillomas and atypical papillomas), 40 (65%) had histologic follow-up. Overall, 15 (38%) of 40 patients had ductal carcinoma in situ (12 cases) or invasive carcinoma at excision (3 cases). Eight cases diagnosed as papilloma had benign follow-up. Slides were available for review in 38 cases and reclassified into benign papilloma with florid hyperplasia and no or minimal atypia (18 cases), papilloma with separate foci of atypical ductal hyperplasia (7 cases), and severely atypical papillomas "suspicious" for papillary carcinoma (13 cases). Carcinoma was identified in 0 (0%), 2 (29%), and 12 (92%) cases, respectively. We conclude that while atypical papillary lesions and papillomas with associated atypical ductal hyperplasia in breast core needle biopsy specimens are associated with a risk of carcinoma, lesions diagnosed as papilloma or papilloma with no or minimal atypia are benign and do not need to be excised.

Primary central nervous system posttransplant lymphoproliferative disorders.

Abstract: Posttransplant lymphoproliferative disorders (PTLDs) represent a spectrum ranging from Epstein-Barr virus (EBV)-driven polyclonal lymphoid proliferations to EBV+ or EBV- malignant lymphomas. Central nervous system (CNS) PTLDs have not been characterized fully. We reviewed the clinical, radiologic, and pathologic features of 12 primary CNS PTLDs to define them more precisely. Patients included 10 males and 2 females (median age, 43.4 years) who were recipients of kidney (n = 5), liver (n = 2), heart (n = 2), peripheral blood stem cells (n = 2), or bone marrow (n = 1). All received immunosuppressive therapy. CNS symptoms developed 3 to 131 months (mean, 31 months) after transplantation. By neuroimaging, most showed multiple (3 to 9) intra-axial, contrast-enhancing lesions. Histologic sections showed marked expansion of perivascular spaces by large, cytologically malignant lymphoid cells that were CD45+, CD20+, EBV+ and showed light chain restriction or immunoglobulin gene rearrangement. In distinction to PTLDs in other organ systems, CNS PTLDs were uniformly high-grade lymphomas that fulfilled the World Health Organization criteria for monomorphic PTLDs. Extremely short survival periods were noted for each CNS PTLD that followed peripheral blood stem cell transplantation. Survival of others with CNS PTLD varied; some lived more than 2 years.

Immunostaining for Human Herpesvirus 8 Latent Nuclear Antigen-1 Helps Distinguish Kaposi Sarcoma From Its Mimickers

Abstract: We assessed the usefulness of a mouse monoclonal antibody (13B10) against human herpesvirus 8 (HHV-8) latent nuclear antigen-1 (LNA-1) in diagnosis of Kaposi sarcoma (KS) and for distinguishing it from various mimickers by studying 50 cases of KS and 53 mimickers (angiosarcoma, 15; kaposiform hemangioendothelioma, 6; spindle cell hemangioma, 3; reactive angioendotheliomatosis, 3; bacillary angiomatosis, 4; acroangiomatous dermatitis, 2; microvenular hemangioma, 2; hobnail hemangioma, 2; pyogenic granuloma, 5; dermatofibroma, 8; arteriovenous hemangioma, 1; verrucous hemangioma, 1; nonspecific vascular proliferation, 1) from patients with or without acquired HIV infection. Immunohistochemical staining was performed on formalin-fixed, paraffin-embedded tissue sections. All 50 cases of KS were positive for HHV-8 LNA-1, with immunolocalization in the nuclei of the spindle cells and cells lining the primitive and thin-walled vascular channels, whereas all 53 mimickers (including 4 lesions from HIV-positive patients) tested negative. The results indicate that positive immunostaining for HHV-8 LNA-1 exhibits high sensitivity and specificity for the diagnosis of KS and is, thus, useful for distinguishing it from the mimickers.

Evaluation of a deidentification (De-Id) software engine to share pathology reports and clinical documents for research.

Abstract: We evaluated a comprehensive deidentification engine at the University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, that uses a complex set of rules, dictionaries, pattern-matching algorithms, and the Unified Medical Language System to identify and replace identifying text in clinical reports while preserving medical information for sharing in research. In our initial data set of 967 surgical pathology reports, the software did not suppress outside (103), UPMC (47), and non-UPMC (56) accession numbers; dates (7); names (9) or initials (25) of case pathologists; or hospital or laboratory names (46). In 150 reports, some clinical information was suppressed inadvertently (overmarking). The engine retained eponymic patient names, eg, Barrett and Gleason. In the second evaluation (1,000 reports), the software did not suppress outside (90) or UPMC (6) accession numbers or names (4) or initials (2) of case pathologists. In the third evaluation, the software removed names of patients, hospitals (297/300), pathologists (297/300), transcriptionists, residents and physicians, dates of procedures, and accession numbers (298/300). By the end of the evaluation, the system was reliably and specifically removing safe-harbor identifiers and producing highly readable deidentified text without removing important clinical information. Collaboration between pathology domain experts and system developers and continuous quality assurance are needed to optimize ongoing deidentification processes.

A molecular mechanism of formalin fixation and antigen retrieval

Abstract: Despite the popularity of antigen-retrieval techniques, the precise molecular mechanism underlying the process remains enigmatic. We examined the molecular features underlying the loss of immunoreactivity following formalin fixation, with subsequent recovery by antigen retrieval. To do this, we first created a molecular model using short peptides that mimic the antibody-binding site of common clinical protein targets. The advantage of this model is that we know the amino acid sequence in and around the antibody-binding site. We observed that some, not all, of the peptides exhibited the formalin-fixation and antigen-retrieval phenomenon. Other peptides did not lose their ability to be recognized by antibody, even after prolonged incubation in formalin. A third, intermediate group exhibited the formalin-fixation and antigen-retrieval phenomenon only if another irrelevant protein was mixed with the peptide before fixation. Amino acid sequence analysis indicates that fixation and antigen retrieval are associated with a tyrosine in or near the antibody-binding site and with an arginine elsewhere, implicating the Mannich reaction as important in fixation and antigen retrieval.

Proliferating pilar tumors: a clinicopathologic study of 76 cases with a proposal for definition of benign and malignant variants.

Abstract: We studied proliferating pilar tumors (PPTs) to establish histologic criteria that could predict behavior. We reviewed all cases in our consultation files (1989-2000) and evaluated 76 cases with meaningful follow-up information. Histologic examination involved attention to tumor silhouette, degree of nuclear atypia, mitotic activity, necrosis, and perineurial or angiolymphatic invasion. Tumors were stratified as follows: group 1 PPTs, circumscribed silhouettes with "pushing " margins, modest nuclear atypia, and an absence of pathologic mitoses, necrosis, and invasion of nerves or vessels; group 2 PPTs, similar to group 1 but manifested irregular, locally invasive silhouettes with involvement of the deep dermis and subcutis; group 3, invasive growth patterns, marked nuclear atypia, pathologic mitotic forms, and geographic necrosis, with or without involvement of nerves or vascular structures. Recurrence occurred in none of 48 group 1 PPTs; 3 (15%) of 20 group 2 PPTs had local regrowth; 4 (50%) of 8 of group 3 PPTs recurred and/or metastasized to regional lymph nodes. The differences between groups 1 and 3 and between 2 and 3 were statistically significant (P = .0002, P < .05, respectively). It seems justifiable to regard group 1 PPTs as benign, group 2 as having potential for locally aggressive growth, and group 3 also as having metastatic potential. The latter 2 categories might be equated with low and high grades of malignancy among PPTs of the skin.

Claudin 4 Protein Expression in Primary and Metastatic Pancreatic Cancer

Abstract: We performed a comprehensive immunohistochemical evaluation of claudin 4 protein expression in paraffin-embedded tissue samples from 72 patients with primary infiltrating pancreatic cancer, 38 patients with metastatic pancreatic cancer, and a panel of normal control tissue samples from various organs. In 11 samples of primary infiltrating pancreatic cancer, foci of pancreatic intraepithelial neoplasia (PanIN) were present and also were analyzed for claudin 4 protein expression. Intense positive claudin 4 immunolabeling was noted within virtually all primary (71/72 [99%]) and metastatic (49/49 [100%]) pancreatic cancer tissue samples analyzed and in 10 of 11 samples of PanIN. In all cases, immunolabeling was noted in a membranous distribution. Claudin 4 protein also was detectable in normal breast, prostate, bladder, and gastrointestinal mucosa, although expression was substantially less intense than that seen in pancreatic cancer tissue samples. Our findings support the use of claudin 4 as a target for novel therapeutics or radioimaging of infiltrating pancreatic cancer. Furthermore, the finding of claudin 4 overexpression within pancreatic intraepithelial neoplasia, the precursor lesion of pancreatic cancer, suggests a potential benefit of imaging claudin 4 before the development of an invasive carcinoma.

Papillary lesions of the breast with and without atypical ductal hyperplasia: Can we accurately predict benign behavior from core needle biopsy

Abstract: Evaluation of papillary lesions of the breast can be difficult, and in core needle biopsy specimens, accurate diagnosis is challenging. Initial studies suggested that all papillary lesions revealed by core biopsy required surgical excision. Recent data suggest that only papillary lesions with atypical ductal hyperplasia (ADH) revealed by core biopsy need surgical excision. We evaluated our experience at the University of Washington Medical Center, Seattle, with papillary lesions with and without ADH on core biopsy to determine whether diagnostic accuracy can be achieved. In 51 core biopsy specimens, we evaluated the presence or absence of ADH: 25 were benign papillomas; 26 were papillomas with ADH. Surgical follow-up was available for 36 cases (11 papillomas and 25 papillomas with ADH). Clinical (radiologic) follow-up was available in 5 papilloma cases (average follow-up, 35.6 months). Follow-up revealed that all papillomas on core biopsy were benign. Excisional biopsy revealed ductal carcinoma in situ or invasive carcinoma in 12 (48%) of 25 papillary lesions with ADH. Benign papillomas can be adequately diagnosed with core biopsy. All papillary lesions with ADH require surgical excision owing to the high rate of associated neoplasia.

Invasive Micropapillary Carcinoma of the Breast

Abstract: We report 62 cases of invasive micropapillary carcinoma of the breast characterized by delicate pseudopapillary structures lacking a fibrovascular core and by tubuloalveolar structures freely floating in clear, empty spaces. All patients but 1 were women (median age, 57 years; range, 25–89 years). Tumor size ranged from 0.7 to 10 cm (median, 2.8 cm); 54 (87%) were grade 3. Psammoma bodies were identified in 29 (47%). Focal to massive lymphatic permeation was present in 39 (63%). Architectural features were retained in the node metastases, dermal lymphatics, and recurrences. Fifty-six patients (90%) had metastatic axillary nodes: 18 tumors were estrogen receptor–positive (32%); 11 were progesterone receptor–positive (20%); HER2/neu was overexpressed in 53 (95%) and p53 in 39 (70%). A peculiar immunoreactivity for MUC1 limited to the cytoplasmic membrane oriented toward the stroma and an absence of immunoreactivity for E-cadherin in the same side of the cytoplasmic membrane indicated inversion of cell polarization and a disturbance in the cell adhesion molecules. Of 41 patients with available follow-up, 29 (71%) had local recurrence (mean, 30 months) and 20 (49%) died of disease. These results underscore the aggressive behavior and poor prognosis of this breast carcinoma variant. Aggressive preoperative neoadjuvant chemotherapy should be considered.

Prominent Clonal B-Cell Populations Identified by Flow Cytometry in Histologically Reactive Lymphoid Proliferations

Abstract: We describe 6 cases from the University of Washington Hematopathology Laboratory (Seattle) in which prominent, clonal, follicle center B-cell populations were identified by flow cytometry and confirmed by molecular methods, but in which the histologic features showed reactive follicular hyperplasia without evidence of bcl-2 overexpression or the t(14;18). The 6 cases included 5 lymph node biopsy specimens and 1 tonsillectomy specimen. Of the 6 cases, 5 occurred in young males (8-28 years) with no known immunologic abnormality; the other case was a 32-year-old, HIV-positive woman. In all 6 cases, clonal CD10+ B cells representing at least 20% of the total B cells were identified. Available clinical follow-up ranging from 13 to 56 months revealed no evidence of lymphoma in any of the 6 patients. Our findings add rare cases of follicular hyperplasia to the list of histologically reactive settings in which clonal B-cell populations might be present.

Hepatocyte paraffin 1 expression in human normal and neoplastic tissues: tissue microarray analysis on 3,940 tissue samples.

Abstract: Hepatocyte paraffin 1 (Hep Par 1) is a monoclonal antibody developed from hepatic tissue from a failed liver allograft. Several studies have shown that Hep Par 1 is a useful marker to differentiate hepatocellular carcinoma (HCC) from other types of adenocarcinoma metastatic to the liver. The aim of our study was the systematic investigation of the epidemiology of Hep Par 1 expression in 3,940 tissue samples using the tissue microarray technique. Strong Hep Par 1 expression was found most frequently in 35 (73%) of 48 HCCs. In nonhepatic tumors, strong Hep Par 1 expression was detected in adenocarcinoma of the lung (2/50), gallbladder (3/31), pancreas (2/48), stomach (3/74), small intestine (1/11), adenoma of the colon with high-grade dysplasia (1/49), adrenal gland carcinoma (1/6), paraganglioma (1/9), and malignant melanoma (2/48). Our data suggest that Hep Par 1 is a highly specific marker for HCC, although several nonhepatic tumors occasionally can show some Hep Par 1 positivity.

Papillomas and Atypical Papillomas in Breast Core Needle Biopsy Specimens

Abstract: We sought to define the risk associated with papillomas and atypical papillomas in breast core needle biopsy specimens from a series of approximately 8,500 biopsies performed during 8 years From a total of 62 papillary lesions (including papillomas and atypical papillomas), 40 (65%) had histologic follow-up Overall, 15 (38%) of 40 patients had ductal carcinoma in situ (12 cases) or invasive carcinoma at excision (3 cases) Eight cases diagnosed as papilloma had benign follow-up Slides were available for review in 38 cases and reclassified into benign papilloma with florid hyperplasia and no or minimal atypia (18 cases), papilloma with separate foci of atypical ductal hyperplasia (7 cases), and severely atypical papillomas “suspicious” for papillary carcinoma (13 cases) Carcinoma was identified in 0 (0%), 2 (29%), and 12 (92%) cases, respectively We conclude that while atypical papillary lesions and papillomas with associated atypical ductal hyperplasia in breast core needle biopsy specimens are associated with a risk of carcinoma, lesions diagnosed as papilloma or papilloma with no or minimal atypia are benign and do not need to be excised

Micromorphometric features of positive sentinel lymph nodes predict involvement of nonsentinel nodes in patients with melanoma.

Abstract: The aim of the present study was to determine whether micromorphometric features of positive sentinel lymph nodes (SLNs) from patients with melanoma are useful for predicting further nodal involvement in completion lymph node dissection (CLND) specimens. Of 986 patients with melanoma undergoing SLN biopsy between March 1992 and February 2001, 175 (17.7%) had at least 1 positive SLN and 140 had subsequent CLND specimens available for review. Further nodal involvement in CLND specimens was present in 24 (17.1%) of 140 patients. Of 8 micromorphometric features of the SLNs that were assessed, the presence of metastases in CLND specimens was correlated significantly with a tumor penetrative depth (maximum distance of melanoma cells from the inner margin of the SLN capsule) of more than 2 mm (P < .05), a deposit size of more than 10 mm 2 (P < .01), the presence of melanoma cells in perinodal lymphatic vessels (P < .01), and the effacement of nodal architecture by metastatic melanoma cells (P < .05). Our results indicate that some morphologic features of melanoma metastases in SLNs predict the likelihood of further nodal involvement in CLND specimens. Until the feasibility of sentinel lymph node (SLN) biopsy and its reliability as a staging procedure were established in the early 1990s, it was the policy of many large melanoma treatment centers worldwide to perform an elective lymph node dissection (ELND) of the relevant regional node field for patients with cutaneous melanomas more than 1.5 mm thick. 1 Because only about 20% of this group of patients had nodal involvement in regional node fields, the remaining 80% of patients undergoing ELNDs were placed unnecessarily at risk of anesthetic complications and surgical morbidity (including acute wound problems, nerve injury and chronic lymphedema). 2,3 It is now well established that SLN biopsy is a minimally invasive procedure that accurately indicates the regional node status of patients with melanoma. Indeed, it has proved to be the single most important prognostic factor for patients with early-stage melanoma. 3-6 Based on the finding of metastatic cells in SLNs, completion lymph node dissections (CLNDs) can now be performed only in selected patients with melanoma, while all other patients are spared this major and potentially morbid surgical procedure. However, among patients with positive SLNs, further nodal involvement in CLND specimens is identified in only 8% to 30% of cases. 7-9 If the pathologic features of patients’ positive SLNs could be used to predict who would not have further nodal involvement in a CLND specimen, these individuals also could be spared such major surgery and its inherent risks. Therefore, this study was performed with the aim of determining whether micromorphometric features of positive SLNs from patients with melanoma are useful for predicting which patients will and will not have further nodal involve