Showing papers on "Myoepithelial cell published in 1992"

Distribution of hyaluronan and its CD44 receptor in the epithelia of human skin appendages

Abstract: Biotinylated hyaluronan (HA) binding complex (HABC) from bovine articular cartilage proteoglycan was used as a histological probe to study the localization of HA in human skin. The distribution of HA was compared with its presumptive cell surface receptor, CD44, using monoclonal antibodies. In epidermis both HA and CD44 were found in the basal and spinous cell layers, but neither was present in the stratum granulosum and stratum corneum. In the keratinizing parts of hair follicles, i.e. in the outer and inner epidermal root sheath, pilosebaceous duct and the actual hair, HA and CD44 were found between the vital but not the terminally differentiated cells. In the sebaceous glands a small amount of HA was found around all cells, whereas CD44 was restricted to the basal cell layer. The secretory acini of the sweat glands stained intensively with anti-CD44 antibodies but only weakly with HABC. In the sweat gland, CD44 was localized on the basal and lateral surfaces of the clear cells, whereas the dark cells and the myoepithelial cells were negative. Both the lower and upper layers of the sweat gland ducts showed a faint but constant staining for CD44 and only minor amounts of HA. While in the keratinizing skin epithelia both HA and its CD44 receptor showed an intense staining with a close co-distribution, in the sweat and sebaceous glands their distribution patterns were not similar. It is suggested that in epithelia with divergent differentiation programs the functions of CD44 and HA may be different.

An immunohistochemical study of the breast using antibodies to basal and luminal keratins, alpha-smooth muscle actin, vimentin, collagen IV and laminin. Part I: Normal breast and benign proliferative lesions.

Abstract: The distribution of simple epithelial (K8/18/ 19) and basal (myoepithelial) (K5/14) keratins, α-smooth-muscle actin, vimentin, collagen IV and laminin in normal mammary glands and in benign proliferative lesions was studied using monoclonal antibodies (mAbs). These antibodies (Abs) identified myoepithelial cells and luminal cells specifically. In lesions with adenosis and papillomas, the two-layered formation resembled that of normal glands with a purely myoepithelial-epithelial differentiation. In scleradenotic lesions, the main cell was of myoepithelial immunophenotype with intermixed trabecular-tubular proliferations of simple-type epithelium. The sclerosis seems to be the result of an irregular basal lamina synthesis by the myoepithelial cells. In contrast to these lesions, epitheliosis represents a purely intraluminal cell proliferation of clearly simple epithelial immunophenotype and of cells with a basal keratin phenotype, lacking myoepithelial differentiation antigen actin. The basal keratin type epithelium may represent post-stem or intermediate cells developing into luminal epithelium. Epitheliosis appears to be a purely epithelial hyperplasia with striking similarity to the regeneration of normal breast epithelium. The different proliferative patterns may give an explanation for differences in potential cancer risks of patients with these lesions.

Keratin profiles in normal/hyperplastic prostates and prostate carcinoma

Abstract: Immunoreactivities in 25 cases of prostatic adenocarcinoma and 10 normal/hyperplastic prostates were investigated in methacarn-fixed, paraffin-embedded serial sections using a panel of nine anti-keratin monoclonal antibodies (mAbs); 34β E12, CK8.12, 312C8-1, CK4.62, RPN1165, RPN1162, 35βH11, CK5, M20, and one of anti-actin mAb, HHF35. In normal/ hyperplastic prostates, RPN1162, 35βH11, CK5 and M20 stained luminal cells without staining basal cells, and 34βE12, CK8.12 and 312C8-1 stained basal cells but not luminal cells. Other mAbs, CK4.62 and RPN1165, stained basal cells as well as luminal cells. All of the mAbs labelling luminal cells stained cancer cells with variable frequencies in a manner unrelated to the grade of tumour differentiation. Of the prostate cancer cases 92% were scored positive with M20, 84% with 35βH11, 80% with CK5, 68% with CK4.62, 60% with RPN1165 and 4% with RPN1162. However, basal cell-specific keratins labelled with 34βE12, CK8.12 and 312C8-1 were totally negative in the cancer cells. HHF35 showed no labelling in normal, hyperplastic or neoplastic epithelial cells of the prostate. Our findings indicate that the major part of the cells of prostatic adenocarcinomas have keratin phenotypes similar to luminal cells but not basal cells, and that no myoepithelial differentiation can be detected in epithelial cell of the prostate. Thus, mAbs for keratins facilitate the identification of epithelial cell phenotypes in normal, benign and malignant conditions of the prostate.

Enhanced synthesis of gelatinase and stromelysin by myoepithelial cells during involution of the rat mammary gland

Abstract: During the involution of the mammary gland there is destruction of the basement membrane as the secretory alveolar structures degenerate. Immunofluorescence staining of sections of rat mammary gland with antibodies to 72 KD gelatinase (MMP-2) and stromelysin (MMP-3) revealed increased production of these two proteinases during involution. This increased expression was mostly restricted to myoepithelial cells. Increased expression during involution was also demonstrated by immunoblotting techniques. Gelatin zymography indicated that the predominant metalloproteinase present in involuting rat mammary glands was a 66 KD gelatinase.

Epithelial-myoepithelial carcinoma of salivary glands.

Abstract: Epithelial-myoepithelial carcinomas comprise approximately 1 % of all salivary gland neoplasms They are preponderantly tumors of the parotid glands with a relatively low mortality but a decided locoregional aggressiveness Histopathologically, the carcinomas are characterized by a dual cell population of epithelial (ductal) cells and myoepithelial cells These cells vary in their dominance and phenotypic expression

Malignant adenomyoepithelioma of the breast. An immunohistochemical, cytophotometric, and ultrastructural study of a case with lung metastases.

Abstract: Adenomyoepithelioma of the breast is a rare tumor that, on the basis of histologic, immunohistochemical, and ultrastructural features, has a bicellular pattern of epithelial and myoepithelial cells regularly distributed in tubular structures. Until now, this tumor was thought to be a benign or low-grade malignant lesion because of possible local recurrences (7 recurrent cases of 60 in the literature). Only one of these cases had nodal involvement, thereby suggesting the possible malignancy of this lesion. This paper reports the first documented case of malignant adenomyoepithelioma with lung metastases presenting the same biphasic pattern as the primary tumor.

Evidence of two distinct epithelial cell types in primary cultures from human sweat gland secretory coil.

Abstract: The human sweat gland secretory coil (SC) is comprised of myoepithelial (ME) and two types of secretory epithelial cells. The secretory cells include beta-adrenergic-sensitive (beta-S) cells [responsive to the beta-adrenergic agonist isoproterenol (IPR)] and beta-adrenergic insensitive (beta-I) cells. We have grown segments of SC in primary culture and found that under the conditions described here, only epithelial cells form outgrowths as indicated by morphological and physiological properties. As in the native SC epithelium, the secretory cells in primary culture were comprised of polygonal epithelial cells with a characteristic hyperpolarization of cell potentials (Vm) to cholinergic stimulation by mecholyl (magnitude of change of Vm = delta Vm = 21.5 +/- 1.3 mV, mean +/- SE, n = number of cells = 44). We have found both beta-S and beta-I cells as determined by unstimulated membrane potentials, sensitivity to IPR, and K+ conductance (GK+). The frequency distribution of unstimulated cells indicated two distinct populations of cells, one with high membrane potentials (Vm = -63 +/- 2.6 mV), which correlated with beta-S cells, and a second with low membrane potentials (Vm = -22 +/- 1.5 mV), which correlated with the beta-I cells. IPR depolarized the Vm of beta-S cells (delta Vm = 11.0 +/- 0.8 mV, n = 25) without affecting the Vm of beta-I cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of mammary growth and function by TGF-beta.

Abstract: We have previously shown that TGF-beta 1 rapidly and reversibly inhibits ductal growth in vivo when administered by miniature slow-release plastic implants. A possible role for endogenous TGF-beta 1 was suggested by the observation that the normal gland displayed substantial, developmentally regulated levels of TGF-beta 1 transcripts and protein. These studies have now been extended to include the other two mammalian TGF-beta isoforms. When tested with slow-release plastic implants, TGF-beta 2 and TGF-beta 3 also caused disappearance of the proliferating mammary stem cell layer, with rapid involution of ductal end buds and cessation of glandular growth. None of the isoforms was active in inhibiting alveolar morphogenesis. We conclude that under the conditions of these tests, the three mammalian isoforms are functionally equivalent. However, striking differences in patterns of gene expression and in the distribution of immunoreactive peptides suggest that TGF-beta 2 was expressed only at low levels, and mainly during pregnancy. TGF-beta 3 was expressed in ductal stroma and epithelium, and was the only isoform detected in myoepithelial cells. Developing alveolar tissue and its associated ducts displayed striking TGF-beta 3 gene expression and immunostaining, which were greatly reduced during lactation. We are now investigating the possibility that the observed high levels of TGF-beta expression in pregnancy, particularly of TGF-beta 3, and the absence of substantial expression of any isoform during lactation, may indicate a role for the TGF-beta in regulating functional differentiation or the onset of milk secretion.

Characterization of four in vitro established canine mammary carcinoma and one atypical benign mixed tumor cell lines

Abstract: Five spontaneous canine mammary tumors were cultured in vitro and cell lines were established. The tumors included three frozen carcinomas, fine-needle aspirate from one fresh carcinoma, and one fresh atypical benign mixed tumor. The cell lines have so far been cultured for about 2 yr and passaged between 45 and 200 times. The cell lines expressed different types of intermediate filaments, including a heterogenous pattern. In some cases no intermediate filaments were expressed. Ultrastructure studies showed epithelial cells and cells intermediate between epithelial and myoepithelial types. Retrovirus associated A-particles were found in two carcinomas. The mixed mammary tumor cell line formed ductlike structures in collagen substrate. The cell lines grew when inoculated s.c. into male nude mice. Two carcinomas caused lymph node metastases in two mice and another carcinoma single lung metastases in one tested mouse. DNA hypodiploidy, studied by flow cytometry, in one of the primary carcinoma was retained in vitro, and this cell line showed polyploidy during later passages. The other cell lines had a more unstable DNA profile, although a tendency for polyploidy was found. These findings were also illustrated in chromosome studies.

Myoepithelial differentiation in benign sweat gland tumors. Demonstrated by a monoclonal antibody to alpha-smooth muscle actin

Abstract: One hundred and two cases of benign sweat gland tumors of the skin were studied for the presence of myoepithelial cells specifically identified by a monoclonal antibody to alpha-smooth muscle actin on paraffin-embedded tissues. The monoclonal antibody gave a positive result in 12 of 12 cases of cylindroma, 14 of 16 cases of spiradenoma, 2 of 2 cases of apocrine tubular adenoma (papillary eccrine adenoma), 5 of 5 cases of apocrine hidrocystoma, 5 of 5 cases of hidradenoma papilliferum, and in 10 of 10 cases of syringocystadenoma papilliferum. Rare myoepithelial cells were detected in only 1 of 10 cases of mixed tumor, apocrine type. There was no immunoreactivity for alpha-smooth muscle actin in eccrine hidrocystoma (2 cases), mixed tumor of eccrine type (2 cases), syringoma (7 cases), hidroacanthoma simplex (1 case), eccrine poroma (14 cases), clear cell hidradenoma (15 cases), and in 1 case of eccrine syringofibroadenoma. Our data support the concept that myoepithelial cells are seen in most sweat gland tumors considered to differentiate toward the secretory coil of the normal sweat gland. In contrast, myoepithelial cells are absent in tumors showing differentiation toward the excretory (ductal) component of the gland.

Sclerosing adenosis of the prostate gland. A lesion showing myoepithelial differentiation.

Abstract: Sclerosing adenosis of the prostate is a rare lesion characterized by the proliferation of variably sized glands in a cellular stroma. We report light microscopic, immunohistochemical, and ultrastructural studies in 22 examples from 15 patients. Two cases were identified in 100 consecutive prostates embedded by a whole organ method, giving a prevalence of 2%. Antibodies directed against the following antigens were used: high-molecular-weight cytokeratin (CKH; 34 beta E12); cytokeratin (CK; AE1/AE3), prostatic acid phosphatase (PAP), prostate-specific antigen (PSA), S-100 protein, muscle-specific actin (HHF35), and vimentin (Vim). Cells within the glandular component demonstrated positive reactivity for CK, CHH, PSA, and PAP, indicating a prostatic epithelial origin. In addition, a distinct population of cells reacting for muscle-specific actin and S-100 protein was identified within this glandular element. Adequate material for ultrastructural study was available in five cases; all showed the presence of flattened cells located between the basement membrane and secretory epithelial cells, which had features typical for myoepithelial differentiation. Although the prostate gland does not normally contain myoepithelial cells, we have documented their consistent presence in this unusual lesion; we believe these cells arise by a metaplastic process from the prostatic basal cells.

The urokinase-system in tumor tissue stroma of the breast and breast cancer cell invasion.

Abstract: The urokinase-system has been implicated in tumor spread. The serine protease urokinase-type plasminogen activator (uPA), its receptor (uPAR) and its inhibitor (PAI-1) are involved in the control of extracellular turnover, cell migration, invasion, cell signalling, proliferation, apoptosis and angiogenesis leading to a variety of different responses, under both physiological and pathological conditions. uPA and PAI-1 were the first novel tumor biological factors to be validated at the highest level of evidence regarding their clinical utility in breast cancer. However, it is unclear whether it is their (relative) levels in the tumor stroma or in the tumor cells themselves that is the most relevant to patients outcome. This is the first study in which tumor cells and stromal tissue of invasive breast carcinomas were separated by laser capture microdissection followed by ELISA-based determination of the uPA, uPAR and PAI-1 levels. In addition, we localized uPA, uPAR and PAI-1 distribution in invasive breast cancer (n=30) and in ductal carcinoma in situ (DCIS, n=30) by immunohistochemistry and in situ hybridization. We have demonstrated that no significant differences between uPA, uPAR and PAI-1 levels in tumor stroma only, tumor cells only and not separated breast cancer tissue exist (p>0.05). Our results suggest that similar expression levels of these factors in both compartments and in not separated breast cancer tissue may have the same impact on the clinical behavior of breast cancer. These results are an important issue for practical use of tissue sampling. For using uPA and PAI-1 levels as prognostic and predictive factors in breast cancer the quantity of tumor stroma in the tumor tissue specimen is not relevant for assessment patients outcome. Our results were confirmed by immunohistochemistry and in situ hybridization analysis showing that in nearly all cases of invasive carcinomas and DCIS fibroblasts as well as macrophages strongly express uPA, uPAR and PAI-1. Prompted by our immunohistological results that nearly all myoepithelial cells of DCIS exhibit uPA, uPAR and PAI-1, we investigated these important host cells in detail. We have demonstrated by multimodal methods that uPAR and PAI-1 protein and mRNA is expressed in most myoepithelial cells of DCIS. Additionally, we furnish evidence that uPAR expression of myoepithelial cells are important for uPAR Vitronectin-associated cell-matrix interaction, which regulates cell adhesion and detachment. We speculate that the loss of the anti-invasive myoepithelial cell layer in DCIS may be triggered by PAI-1 and could be an early sign of subsequent tumor cell invasion.

The solid variant of adenoid cystic carcinoma of the cervix.

Abstract: We studied seven examples of the solid variant of adenoid cystic carcinoma of the uterine cervix in postmenopausal women who presented with vaginal bleeding and a large ulcerated or polypoid cervical mass. The tumors lacked the characteristic cribriform pattern of conventional adenoid cystic carcinoma. The neoplastic cells were small, undifferentiated, or basaloid and grew in cords, nests, trabeculae, and nodules. Foci of squamous cell carcinoma were seen in three tumors and areas of necrosis in four. A characteristic feature was the production of abundant periodic acid-Schiff's procedure (PAS)-positive basement membrane material that was immunoreactive for collagen IV and that in some areas compressed tumor cells. Electron microscopy on three cases showed globules and cylinders of redundant basal lamina. The tumor cells were joined by desmosomes and contained bundles of tonofilaments. Material similar to basement membrane material appeared to be intracytoplasmic in two tumors. No neurosecretory granules or myoepithelial cells were found. Four deaths were tumor related. Two patients are currently alive, but with local recurrence or metastases; another is alive and well 19 months after surgery. We believe that the solid variant of adenoid cystic carcinoma of the cervix is a distinctive neoplasm that should be separated from small cell carcinomas with or without endocrine features, adenoid basal cell carcinoma, and squamous cell carcinoma.

Sialoblastoma: a case report and review of the literature on congenital epithelial tumors of salivary gland origin.

Abstract: The histologic, immunohistochemical, and ultrastructural features of a congenital epithelial tumor of the parotid were studied. The tumor was characterized by solid nests of epithelial cells intermingled with proliferating ductal structures lined by a double layer of cells. Immunoperoxidase staining for cytokeratin, vimentin, actin, and S-100 protein showed the presence of cytokeratin in the ductal cells as well as the presence of vimentin, actin, and S-100 protein in the outermost layer of the ducts. The solid nests were focally reactive to S-100 and vimentin. Ultrastructural examination revealed myoepithelial cells with replication of basement membrane material. The tumor recurred 17 months after excision without lymph node involvement or metastasis. The term "sialoblastoma" is favored. Review of the literature on congenital, epithelial salivary gland tumors showed that a few cases recurred locally and only one case had regional lymph node involvement. No distant metastasis has been reported.

Intraductal growth of malignant mammary myoepithelioma.

Abstract: This report describes the histologic and immunohistologic features of an intraductal myoepithelial tumor that developed in the breast of a 61-year-old woman. Histologically, the tumor proliferated intraductally, with both a comedo or doughnut pattern and a solid pattern containing narrow fibrovascular cores, mimicking what appeared to be a conventional intraductal carcinoma. No fine papillary or arborizing growth or cribriform formation was observed. Tumor cells at the ductal peripheral zone were polygonal and clear with abundant glycogen in the cytoplasm; they were transformed into nonclear cells with slightly eosinophilic cytoplasm toward the center of the involved ducts. Occasionally, nonclear cells were elongated, with a centrally located cigar-shaped nucleus. These elongated or spindle cells tended to show a fascicular and streaming pattern similar to that of a smooth muscle tumor. Immunohistochemically, alpha smooth muscle actin (alpha-SM-actin) and S-100 protein were expressed in most of the nonclear cells. While clear cells also had a positive reaction for S-100 protein, they were mostly negative or barely positive for alpha-SM-actin. Epithelial membrane antigen (EMA) was also positive in a certain number of polygonal cells. These results support the myoepithelial nature of the present tumor, and some cells might also be immunologically differentiated into ductal epithelial cells. In addition to cytological atypia, frequent mitoses, and central necrosis within ducts, there was a minimal but evident stromal invasion, suggesting histological malignancy in this peculiar tumor.

Colloid Cyst of the Third Ventricle: A Comparative Ultrastructural Study of Neuraxis Cysts and Choroid Plexus Epithelium

Abstract: Thirteen colloid cysts (CC), four Rathke cleft cysts (RCC), three follicular cysts of normal pituitary gland (FCP), four enterogenous cysts (EC), three normal choroid plexi (CP), three choroid plexus pa-pillomas (CPP), and several samples of normal bronchial mucosa and ependyma were studied by electron microscopy. The ultrastructure of most of the CC was indistinguishable from that of RCC, FCP, EC, and normal bronchial mucosa in demonstrating nonciliated and ciliated epithelial cells, goblet cells, basal cells, and intermediate forms, some showing evidence of early squamous differentiation. Two CC displayed mostly squamous differentiation, and one contained basally situated cells resembling myoepithelial cells. Although the RCC and FCP displayed features similar to those of CC, they also contained cells with electron-dense granules indicating pituitary hormone production and scattered cells showing oncocytic change. EC were lined by either squamous cells or mucin-producing columnar cells. Every CC, RCC, F...

Immunohistochemical and ultrastructural correlates of muscle-actin expression in pleomorphic adenomas and myoepitheliomas based on comparison of formalin and methanol fixation.

Abstract: The degree and range of differentiation of the cells referred to as myoepithelial-like in pleomorphic adenomas and the tumour cells of myoepitheliomas are not definitely established. This type of information is critical for establishing reliable diagnostic criteria, such as expression of muscle-specific actin and ultrastructural identification of myofilaments, in these and other salivary gland tumours. Pleomorphic adenomas (18) and myoepitheliomas (5), of which 10 cases were fixed only in formalin and 13 cases where tissues were fixed in both formalin and methanol/acetic acid, were studied. Each tumour and normal accompanying parotid was immunostained with two monoclonal antibodies for smooth muscle actin, HHF35 and MSA. Staining of myoepithelial cells was absent in certain samples of normal gland with both HHF35 (15%) and MSA (69%) when formalin-fixed tissue was used. Using formalin-fixed tissue from 15 pleomorphic adenomas/myoepitheliomas, 2 (14%) had focal positivity with HHF35, while 8 cases (57%) were positive with MSA. However, a certain degree of false positivity was suspected since in samples of normal parotid, both acinar and duct cells were frequently stained, particularly with MSA. With methanol/ acetic acid-fixed tissue only 4 of 13 cases (31%) were positive with either MSA or HHF35 and 2 of these only had a minor proportion of the tumour cells expressing muscle-specific actin. Using alcohol-fixed tissue, myoepithelial cells were strongly stained in all examples of normal parotid gland with both anti-actin antibodies. In 5 cases examined by electron microscopy, there was no apparent correlation between immunohistochemical results and the presence or absence of cytoplasmic filament accumulation. The results indicate considerable tumour cell heterogeneity in muscle-specific actin expression and suggest that non-luminal cells in pleomorphic adenomas and the tumour cells in myoepitheliomas may differentiate as classical myoepithelial cells, as partially differentiated (i.e. modified myoepithelial cells) or as the counterpart of basal cells present in the intra- and interlobular ducts of normal salivary gland.

Tumor types derived from epithelial and myoepithelial cell lines of R3230AC rat mammary carcinoma.

Abstract: Epithelial and myoepithelial cells coexist in the rat R3230AC mammary tumor. To test the hypothesis that these two cell types constitute interactive but independent neoplastic populations, we obtained in vitro cell lines with epithelial or myoepithelial patterns and transplanted them in syngeneic animals. One stabilized line (EPI) and four cloned lines (A, C, D, E) with epithelial characteristics, confirmed by positive reactions for keratins in immunocytochemical and immunoblot tests, constantly gave rise in vivo to carcinomas, which, however, lacked structural and functional patterns typical of the original tumor. A fusiform shape and immunocytochemical characteristics of myoepithelial cells were observed in three clones (H, I, L), which in vivo gave rise to sarcomatous and mixed carcinosarcomatous neoplasms. These data are consistent with the above hypothesis and indicate that breast carcinomas derive from epithelial cells, while sarcomatous and carcinosarcomatous neoplasms can originate from myoepithelial cell proliferation. This study provides data suggesting myoepithelial cell involvement in the development of pathological entities occurring in the human breast and displaying mixed epithelial and stromal neoplastic components, i.e., cystosarcoma phylloides and sarcomatous metaplasia in carcinomas.

Basement membrane proteins in salivary gland tumours. Distribution of type IV collagen and laminin.

Abstract: Immunohistochemical localization of type IV collagen and laminin in normal salivary glands and in salivary gland tumours of various types was studied using rabbit antisera. In normal salivary glands, type IV collagen and laminin were co-localized in basement membranes surrounding acini, ducts, fat cells and peripheral nerves. In salivary gland tumours, three main patterns of co-expression of these basement membrane proteins were distinguished. Linear basement membrane-like staining was detected in duct-cell-derived benign salivary gland tumours and in acinic cell carcinomas. In invasive lesions, however, these basement membrane proteins were distributed in an irregular, interrupted manner, and in many cases they were completely absent. Both benign and malignant salivary gland tumours which have a prominent myoepithelial cell component display a particular deposition of basement membrane molecules adjacent to the modified myoepithelial cells, and at the margins of extracellular matrix deposits within these tumours.

Characterization of a novel cell line from pleomorphic adenoma of the parotid gland with myoepithelial phenotype and producing interleukin-6 as an autocrine growth factor.

Abstract: A cell line was obtained from a primary culture of a pleomorphic adenoma of the parotid gland in a 24-year-old woman. The cells of the line (PA 16/23) grew spontaneously in minimal culture conditions and showed stable morphologic characteristics over 30 passages. PA 16/23 cells had immunophenotypic and ultrastructural features similar to those of transformed myoepithelial cells, which are regarded as the precursors of pleomorphic adenomas. Furthermore, these cells have been demonstrated immunocytochemically to contain interleukin-6 (IL-6) on light and electron microscopic examination. IL-6 also has been found by enzyme-linked immunosorbent assay in the culture supernatant and has been proven to be capable of stimulating growth of the PA 16/23 cells.

Sebaceous differentiation in a breast carcinoma with ductal, myoepithelial and squamous elements.

Abstract: uncertain whether the tumour is derived from vascular or lymphatic endothelium and it is frequently negative for von Willebrand’s factor. Histologically, angiosarcoma of the face and scalp is indistinguishable from those lymphangiosarcomas that arise as a complication of preceding chronic lymphoedema4. Telangiectasia is a feature of xeroderma pigmentosum and was present in our case. It is possible that endothelial cells lining such abnormal ectatic vascular spaces might have given rise to this tumour. Angiomas are a recognized, although uncommon, feature of xeroderma pigmentosum’. The immunocytochemical findings in this case confirmed the histological diagnosis of angiosarcoma and facilitated the exclusion of sarcomatoid carcinoma and melanoma. Our finding of positive immunostaining with PGP 9.5 is in keeping with the previously reported expression of this in vascular tumours of the liver5. The development of angiosarcoma in association with xeroderma pigmentosum raises the possibility that UV induced damage might be implicated in the pathogenesis of the tumour. However, angiosarcoma of the face and scalp is described in Negro patients and also develops in patients with a full head of hair, affording good protection from sunlight. Angiosarcoma is known to arise in areas of previous radiotherapy but in vitro repair of X-ray damaged cells from patients having xeroderma pigmentosum is normal in contrast with the considerably reduced repair following UV irradiation, suggesting that different enzyme pathways are involved in the repair processes6. On the other hand, the increased incidence of malignancy at sites not exposed to UV radiation suggest increased susceptibility to non-UV induced damage to DNA, perhaps mediated through dietary and environmental chemical carcinogens. It is, therefore, of further interest that our patient also developed bone marrow aplasia, possibly indicating that the haemopoietic stem cells were also abnormally sensitive to mutagens.

Immunogold localization of actin and cytokeratin filaments in myoepithelium of human parotid salivary gland.

Abstract: Myoepithelial cells of salivary gland are uniquely specialized cells; their function is unclear, but the considerable complement of muscle-specific actin suggests contractility is one function. By routine transmission electron microscopy myofilament visualization is variable. Some myoepithelial cells appear to have limited and only focal aggregates of myofilaments, while others seem to have readily appreciated myofilaments within a longitudinally oriented cytoplasmic zone at the basal portion of the cell. However, immunogold electron microscopy using the anti-muscle-specific actin antibody, HHF35, while indicating a basal distribution for the muscle-isoform of actin in a platelike fashion in certain myoepithelial cells, also reveals that others associated with both intercalated ducts and acini have a more generalized distribution of myofilaments throughout the cytoplasm. Actin was also noted within tonofilaments and double immunogold labeling using both the HHF35 and AE1/AE3 (anticytokeratins) antibodies confirmed the variable interrelationship of these two filaments. Within any one myoepithelial cell, actin and cytokeratins might colocalize in some areas of the cytoplasm containing filaments, but not in adjacent zones. These results suggest that intermediate filaments and myofilaments are complexly organized in myoepithelial cells, and that quantitative and qualitative differences exist in the expression and distribution of intermediate filaments and myofilaments. These cells are likely structurally, if not functionally, heterogeneous.

Antigenic profile of the human lacrimal gland.

Abstract: The antigenic profile of 13 normal formalin-fixed, paraffin-embedded human main and accessory lacrimal glands, biopsied from patients aged 11 to 78 years, was studied using a panel of 27 polyclonal and monoclonal antibodies. Secretory cells of lacrimal acini reacted with antibodies to S-100 protein and simple epithelium-type cytokeratins CK 7, CK 8, CK 18, and CK 19. Their luminal membranes were labeled with antibodies to carcinoembryonic antigen, epithelial membrane antigen, and epithelial glycoproteins recognized by Ber-EP4. Myoepithelial cells were often immunopositive for S-100 protein, vimentin, glial fibrillary acidic protein (GFAP), and alpha-smooth muscle actin. More rarely, they reacted with antibodies recognizing CK 5, CK 13, and CK 14, which consistently labeled the basal cells of lacrimal ducts. Unlike myoepithelial cells, basal ductal cells were immunopositive for CK 7, CK 8, CK 18, and CK 19. In main excretory ducts, dendritic melanocyte-like cells co-expressing vimentin and S-100 protein in...

Primary malignant lymphoma of the salivary gland: a tumor of mucosa‐associated lymphoid tissue

Abstract: The clinical, morphologic and immunohistochemical features of 10 cases of the low-grade mucosa-associated lymphoid tissue (MALT) lymphoma of salivary glands are described. Although the initial histologic diagnosis in nine of these cases was myoepithelial sialadenitis, the diagnosis of primary salivary gland MALT lymphoma was based on the demonstration of light chain restriction and on morphologic characteristics. Histologic study showed a characteristic cytology, which included centrocytoid cells (composed of small centrocytes and monocytoid B cells) and a varying degree of plasma cell differentiation; the occurrence of epithelial or acinar invasion by neoplastic centrocytoid cells; and the presence of reactive lymph follicles among the neoplastic cells. Furthermore, multinucleate giant cells resembling Warthin-Finkeldey cells were detected in seven cases. In the light of these findings, cases previously diagnosed as myoepithelial sialadenitis require careful assessment and nine out of 32 cases are, in reality, examples of primary salivary gland MALT lymphomas. Immunohistochemical analysis of paraffin sections revealed the following characteristic immunophenotype of MALT lymphoma: L26, KiB3 and LN2 positive, and a monotypic immunoglobulin pattern (predominantly IgM/kappa). It was of interest that salivary gland parenchyma, infiltrated by neoplastic centrocytoid cells, reacted with LN3 for cells expressing human leukocyte antigen-DR (HLA-DR) antigens. Whereas salivary gland epithelia devoid of a neoplastic invasion were invariably negative for LN3. This suggests a lymphocyte-mediated role in salivary epithelial HLA-DR expression. It appears that HLA-DR expression is an inducible phenomenon in MALT lymphomas of salivary gland.

Myoepithelioma of the lacrimal gland: report of a case with spindle cell morphology.

Abstract: The case is described of a 23-year-old female patient presenting with unilateral proptosis, headaches, and transient epiphora. Surgery revealed an encapsulated tumour composed exclusively of spindle-shaped cells within a richly vascularised myxoid stroma. Immunohistochemical staining showed focal positivity for smooth muscle actin, vimentin, and glial fibrillary acidic protein. These combined findings are interpreted as providing evidence of a myoepithelioma, which may be regarded as a monomorphic adenoma consisting solely of myoepithelial cells. To our knowledge this is only the second report of such a tumour in the lacrimal gland.