Showing papers on "Clear-cell sarcoma published in 2006"
TL;DR: EWS-CREB1 may define a novel subset of CCS that occurs preferentially in the gastrointestinal tract and shows little or no melanocytic differentiation, which is not a necessary feature of sarcomas with gene fusions involving CREB family members.
Abstract: Purpose: Clear cell sarcoma (CCS) usually arises in the lower extremities of young adults and is typically associated with a t(12;22) translocation resulting in the fusion of EWS ( EWSR1 ) with ATF1 , a gene encoding a member of the cyclic AMP–responsive element binding protein (CREB) family of transcription factors. CCS arising in the gastrointestinal tract is rare and its pathologic and molecular features are not well defined. Experimental Design: We report a novel variant fusion of EWS to CREB1 , a gene at 2q32 encoding another CREB family member highly related to ATF1, detected in three women with gastrointestinal CCS. All three cases contained an identical EWS-CREB1 fusion transcript that was shown by reverse transcription-PCR. In two of the cases tested, EWS gene rearrangement was also confirmed by fluorescence in situ hybridization and the EWS-CREB1 genomic junction fragments were isolated by long-range DNA PCR. Results: Morphologically, all three tumors lacked melanin pigmentation. By immunohistochemistry, there was a strong and diffuse S100 protein reactivity, whereas all melanocytic markers were negative. Ultrastructurally, two of the cases lacked melanosomes. The melanocyte-specific transcript of MITF was absent in two cases, and only weakly expressed in the third case. The Affymetrix gene expression data available in one case showed lower expression of the melanocytic genes MITF, TYR , and TYRP1 , compared with four EWS-ATF1 -positive CCSs of non-gastrointestinal origin. Conclusions: EWS-CREB1 may define a novel subset of CCS that occurs preferentially in the gastrointestinal tract and shows little or no melanocytic differentiation. Thus, evidence of melanocytic lineage or differentiation is not a necessary feature of sarcomas with gene fusions involving CREB family members.
288 citations
TL;DR: It is shown that EWS-ATF1 occupies the MITF promoter, mimicking melanocyte-stimulating hormone (MSH) signaling to induce expression of MITF, the melanocytic master transcription factor and an amplified oncogene in melanoma.
187 citations
TL;DR: By identifying patients at greatest risk for distant metastasis and, hence, most likely to benefit from adjuvant therapy, the grading of Sarcomas has been one of the most important contributions pathologists have made to the treatment of sarcomas.
Abstract: By identifying patients at greatest risk for distant metastasis and, hence, most likely to benefit from adjuvant therapy, the grading of sarcomas has been one of the most important contributions pathologists have made to the treatment of sarcomas. Over the years, many grading schemes have been proposed and validated as efficacious. The three-tier system proposed by the French Federation of Cancer Centres is precisely defined, easy to use, and is the most widely employed. However, no system performs perfectly on all sarcomas. Sarcomas that do not lend themselves well to grading include (i) those in which grade provides no incremental information over histological subtypes (e.g. well-differentiated liposarcoma/atypical lipomatous neoplasm, Ewing's sarcoma); (ii) tumours traditionally considered "ungradable" (e.g. epithelioid sarcoma, clear cell sarcoma, angiosarcoma); and (iii) sarcomas that customarily have been graded but in which grade has recently been shown not to correlate well with outcome (e.g. malignant peripheral nerve sheath tumour). Consequently, several sarcoma-specific risk stratification schemes have been proposed. The future may well witness a synthesis of these two approaches. Nomograms, which incorporate clinical, histological and demographic findings, have proved accurate in predicting disease-specific survival in sarcomas. Diagnosis and grading are increasingly based on tissue obtained by core needle biopsy, which poses new challenges for pathologists, particularly if neoadjuvant therapy is to be given. Grading on needle biopsies may require a two-tier grading system (i.e. low versus high grade) and a close dialogue with clinicians to resolve ambiguities.
128 citations
TL;DR: The detection of EWS‐ATF1 fusion transcripts is helpful to rule out a metastatic melanoma and the diagnosis of CCS usually is easy but may be challenging in unusual sites.
Abstract: BACKGROUND.
Clear cell sarcoma (CCS) is a rare tumor with a very poor prognosis that occurs predominantly in the distal extremities of young adults. Most patients bear the t(12;22) reciprocal translocation, which involves the EWS and ATF1 genes. The diagnosis of CCS usually is easy but may be challenging in unusual sites, and the detection of EWS-ATF1 fusion transcripts is helpful to rule out a metastatic melanoma.
METHODS.
Forty-four patients with CCS and 14 conventional melanomas were examined for the presence of EWS-ATF1 transcripts by using real-time polymerase chain reaction (PCR) analysis on paraffin embedded tissues, including frozen samples for 9 CCS samples and 9 melanoma samples. Prior to molecular analysis, the diagnosis of CCS was considered certain in 35 patients and as probable in 9 patients on the basis of location, histologic features, and immunohistochemical profile. Treatment modalities and follow-up were available for 41 patients with CCS.
RESULTS.
EWS-ATF1 fusion transcripts were detected in 38 paraffin embedded CCS tissues (86% of all samples; 93% of interpretable samples), 3 samples (7%) were negative, and 3 samples (7%) were considered uninterpretable. Fusion transcripts were detected in 7 of 9 samples for which the diagnosis of CCS was considered probable. EWS-ATF1 transcripts were not detected in the 14 samples of melanoma. Results from frozen tissues were concordant with those from all corresponding paraffin embedded samples. Twenty-eight of 41 patients (68%) experienced lymph node and/or distant metastasis, and the 5 year-survival rate was 44%. Mitotic index and histologic grade were predictive of survival and distant metastasis.
CONCLUSIONS.
The results of this study showed that the molecular detection of EWS-ATF1 fusion transcript by real-time PCR on paraffin embedded tissues is a sensitive and specific method for the diagnosis of CCS. It is an efficient tool for the diagnosis of unusual tumors, especially with regard to its distinction from melanoma. The current results also confirmed the poor prognosis for patients with this tumor type. Mitotic index and grade were predictive factors for survival and distant metastasis. Cancer 2006. © American Cancer Society.
78 citations
TL;DR: An unusual stomach tumor with microscopic and immunohistochemical characteristics of an osteoclast-rich tumor of the gastrointestinal tract with features resembling those of clear cell sarcomas of soft parts is reported.
Abstract: Clear cell sarcoma is a high-grade sarcoma with morphological features resembling those of malignant melanoma. An osteoclast-rich tumor of the gastrointestinal tract with features resembling those of clear cell sarcomas of soft parts is very rare. Herein, we report an unusual stomach tumor with microscopic and immunohistochemical characteristics of an osteoclast-rich tumor of the gastrointestinal tract with features resembling those of clear cell sarcomas of soft parts. The tumor cells were predominantly oval, admixed with some round and spindle elements arranged in nests and fascicles, and admixed with scattered osteoclast-like multinucleated giant cells. Neoplastic cells were positive for S-100 protein, and osteoclast-like multinucleated giant cells were immunoreactive to CD68. The unusual morphology of the tumor caused significant diagnostic difficulties. The differential diagnosis included gastrointestinal stromal tumor, primary or metastatic melanoma, and epithelioid malignant peripheral nerve sheath tumor. To the best of our knowledge, this is possibly the second description of an osteoclast-rich tumor of the gastrointestinal tract with features resembling those of clear cell sarcomas of soft parts.
53 citations
TL;DR: Clear cell sarcoma maintains the status of a unique yet enigmatic clinicopathologic entity of ever increasing complexity 40 years after its original description by an extraordinarily gifted man.
Abstract: Clear cell sarcoma of tendons and aponeuroses is a unique sarcoma initially described by Dr Franz M. Enzinger. The tumor has a proclivity to involve the tendons and aponeuroses of distal extremities of relatively young individuals and is characterized by multiple local recurrences with late metastases and a high rate of tumor deaths. Since its seminal description in 1965, there have been many studies verifying the uniqueness of this entity and probing its differentiation. Ultrastructural and immunohistochemical studies have shown melanocytic differentiation, whereas molecular genetic studies have shown cytogenetic rearrangements resulting in a EWSR1-ATF1 fusion gene that is characteristic but not entirely unique for clear cell sarcoma (similar fusion genes are also seen in angiomatoid fibrous histiocytoma). Detection of this fusion gene and the absence of BRAF gene mutations clearly distinguish clear cell sarcoma from cutaneous melanoma. Adverse prognostic factors identified to date include larger tumor size and any microscopic tumor necrosis. Surgery is the mainstay of treatment for this high grade sarcoma, with chemotherapy having little effect. Although the melanocytic differentiation of clear cell sarcoma is indisputable, its precise lineage remains unclear. Thus, clear cell sarcoma maintains the status of a unique yet enigmatic clinicopathologic entity of ever increasing complexity 40 years after its original description by an extraordinarily gifted man.
44 citations
TL;DR: The sentinel node (SN) procedure might be a useful and accurate staging procedure in CCS patients, comparable to the situation in melanoma.
Abstract: Clear cell sarcoma (CCS), also known as clear cell sarcoma of tendons and aponeuroses or malignant melanoma of soft tissue, is a rare malignant tumor and is histogenitically related to melanoma. The aim of this study was to describe our experience with the sentinel node (SN) procedure for CCS patients and to discuss the potential value of this technique for CCS patients. Five patients with a subcutaneous CCS, who underwent an SN procedure, are described. Two patients had positive SNs, with additional tumor positive nodes in both lymph node dissection specimens. Only the patients with tumor positive SNs developed recurrent disease during an average follow-up of 33 months. None of the negative SN patients developed recurrent disease and all were alive after an average follow-up of 39 months. SN status seems to predict additional nodal involvement and recurrent disease as well as survival. The SN procedure might be a useful and accurate staging procedure in CCS patients, comparable to the situation in melanoma.
38 citations
TL;DR: Demonstration of SYT-SSX and EWS-ATF1 fusion assists in the diagnosis of synovial and clear cell sarcomas in unusual locations, such as the gastrointestinal tract, where these tumors occur with low frequency.
Abstract: Cytogenetic discoveries of balanced translocations in soft tissue tumors have opened the way to molecular genetic definition of these translocations as gene fusions from the late 1980s. Many sarcomas are known to have such fusions, and the demonstration of the fusion transcripts in tumor tissue is of great value in specific diagnosis of synovial sarcoma (SYT-SSX), Ewing sarcoma (EWS-Fli1), clear cell sarcoma (EWS-ATF1), myxoid liposarcoma (FUS-CHOP), and other sarcomas. These translocations are believed to be disease-specific and pathogenetic forces, despite occasional observations to the contrary. Demonstration of SYT-SSX and EWS-ATF1 fusion assists in the diagnosis of synovial and clear cell sarcomas in unusual locations, such as the gastrointestinal tract, where these tumors occur with low frequency. Demonstration of sarcoma translocations and their fusion by different assays is well established; use of in situ hybridization is limited by availability of specific probes. In two exceptional instances, the same translocation and gene fusion occurs in two unrelated diseases: ETV6-NTRK fusion in infantile fibrosarcoma and secretory carcinoma of the breast, and ALK-TPM3 fusion in inflammatory myofibroblastic tumor and large cell anaplastic lymphoma. Thus, the target cell of the genetic change is an important factor to define the resulting disease. Activating mutations in two related receptor tyrosine kinases (RTKs), KIT, and platelet-derived growth factor receptor alpha (PDGFRA) is central to the pathogenesis of gastrointestinal stromal tumors (GISTs), and countering the mutational activation by specific tyrosine kinase inhibitors, such as Imatinib mesylate, is now standard treatment for metastatic GISTs. KIT exon 11 mutations (in frame deletions, point mutations, and duplications) occur in GISTs of all locations, whereas a characteristic exon 9 insertion-duplication AY502-503 is nearly specific for intestinal vs gastric tumors. In contrast, PDGFRA mutations are nearly specific for gastric GISTs, especially those with epithelioid morphology. Mutation type influences therapy responsiveness, but fortunately very few GISTs carry primarily Imatinib-resistant mutations. Secondary drug resistance acquired during Imatinib treatment based on new, Imatinib-resistant mutations is a major problem limiting treatment success. Loss of NF2 tumor suppressor gene in a biallelic fashion is believed to be central in the pathogenesis of neurofibromatosis 2 (NF2) associated and sporadic schwannomas and meningiomas. The mechanism includes nonsense or missense mutation in NF2 gene, and loss of the other NF2 allele as a part of losses in chromosome 22q. Schwannoma types may differ in their pathogenesis: gastrointestinal schwannomas lack NF2 changes suggesting a different pathogenesis. Intraneural and sclerosing perineuriomas display similar NF2 gene alterations as seen in meningioma, indicating a similar pathogenesis and molecular homology. Specific viral sequences of human herpesvirus 8 (HHV8) are diagnostic markers for Kaposi sarcoma (KS), and are absent in angiosarcoma. Despite discovery on simian virus SV40 sequences in mesothelioma as a possible pathogenetic factor, recent studies suggest that the presence of these sequences may be artifactual and based on common presence of some SV40 sequences as PCR contaminants.
38 citations
TL;DR: This case illustrates the necessity of a multimodal approach to tumor diagnosis, and the utility of cytogenetics and molecular pathology in confirming the diagnosis of CCS-ST and eliminating conventional metastatic or primary visceral malignant melanoma as a consideration.
Abstract: Clear cell sarcoma of soft tissue (CCS-ST) is a rare malignant neoplasm characterized by a tumor-defining translocation [t(12;22) (q13;q12)], resulting in the EWS-ATF1 gene fusion. An extremely limited number of visceral CCS-ST cases have been reported in the literature. Here the authors report a visceral CCS-ST in a Hispanic adolescent male with a large infiltrative mass involving the small bowel. The tumor was evaluated by light microscopy, immunocytochemistry, electron microscopy, cytogenetics, and molecular genetics. The tumor cells were strongly positive for S-100 protein, but negative for HMB-45. Rare premelanosomes were identified only after an extensive search with electron microscopy. Cytogenetics showed a characteristic t(12;22)(q13;q12) for CCS-ST with isochromosome 18q and trisomy 22. An EWS exon 8 sense primer and an antisense ATF1 primer were employed for detection of the CCS-ST tumor-defining EWS-ATF1 translocation, using reverse transcriptase-polymerase chain reaction techniques (RT-PCR), and the fusion gene breakpoint underwent DNA sequencing. This tumor is exceptional, because it is the first visceral CCS-ST that has been confirmed by RT-PCR and DNA sequencing. This case also illustrates the necessity of a multimodal approach to tumor diagnosis, and the utility of cytogenetics and molecular pathology in confirming the diagnosis of CCS-ST and eliminating conventional metastatic or primary visceral malignant melanoma as a consideration.
36 citations
TL;DR: An unusual case of clear cell sarcoma of tendons and aponeuroses overlying the scapular region and with secondary osseous extension in the lower scapula is presented.
Abstract: Clear cell sarcoma of tendons and aponeuroses (CCSTA) appears usually in the extremities and rarely in the trunk. We present an unusual case of CCSTA overlying the scapular region and with secondary osseous extension in the lower scapula. The patient underwent a wide local excision with removal of the tumor and the lower two thirds of the scapula. He had no local recurrences but he developed lung metastases after 5 months in spite of postoperative chemotherapy. He finally died ten months later. The patients with CCSTA have a variable unpredictable course. Despite treatment the overall prognosis is poor.
35 citations
TL;DR: Mismatch repair, and consequently genomic instability may contribute to tumorigenesis in melanoma but not clear cell sarcoma, and immunostaining for hMLH1 and hMSH2 and MSI analysis may be helpful in the differential diagnosis of large soft tissue or visceral malignancies with melanocytic differentiation.
TL;DR: The CD117 immunoreactivity may prove useful in the differential diagnosis of deep soft tissue or visceral lesions with melanocytic differentiation; positive staining results exclude clear cell sarcoma, but are compatible with metastatic melanoma.
Abstract: Context.—Clear cell sarcoma is a malignant soft tissue tumor with melanocytic differentiation. Molecular methods are sometimes necessary to identify the unique t(12; 22)(q13;q12) translocation and differentiate clear cell sarcoma from melanoma. Objective.—To determine whether CD117 immunoreactivity may be useful in separating melanoma from clear cell sarcoma. Design.—We identified 20 tumors listed in our surgical pathology files that were diagnosed as clear cell sarcoma or in which clear cell sarcoma was strongly considered. These were tested for the presence of the t(12;22) translocation by reverse transcriptase/polymerase chain reaction and sequencing from paraffin-embedded tissue. Tumors with a t(12;22) translocation were immunostained with an antibody to CD117 and compared with 16 similarly stained metastatic melanomas. Results.—Twelve tumors from 9 patients demonstrated t(12;22). No metastatic melanomas demonstrated t(12;22). None of the 12 clear cell sarcomas showed membrane or cytoplasmic ...
TL;DR: The cytology of a case of CCS is described, with emphasis on the so called “tigroid background,” which is a nonspecific feature and has been described in various other tumors, but to the best of the authors' knowledge, not in CCS.
Abstract: Clear-Cell Sarcoma (CCS) is a rare malignant soft tissue tumor of young adults that often metastasizes to the lymph nodes. The fine needle aspirate cytology (FNAC) findings of CCS have been described previously and it is included in the cytological category of polygonal soft tissue tumors. We describe the cytology of a case of CCS, with emphasis on the so called “tigroid background.” Though this tigroid background is a nonspecific feature and has been described in various other tumors, to the best of our knowledge, it has not been described in CCS. This feature may be useful in the recognition of CCS. Diagn. Cytopathol. 2006;34:355–357. © 2006 Wiley-Liss, Inc.
TL;DR: The presentation, treatment, technique of complete resection, and outcome of a 23-month-old girl with clear cell sarcoma of the right kidney with cavo-atrial tumor thrombus is described.
TL;DR: Because there was no evidence of either cutaneous or ocular primary melanoma, the tumor was thus diagnosed as primary colonic malignant melanoma and the possibility of metastasis from another more common primary site must be ruled out.
Abstract: Primary malignant melanoma originating in the digestive tract is extremely rare. A case of primary malignant melanoma in the descending colon is described. The tumor was an elevated mass with surface necrosis. Histologically, tumor cells were arranged with compact nests surrounded by fibrous stroma. The tumor cells had pleomorphic nuclei and rich cytoplasm. In some areas, cells of signet ring-like appearance were found. An immunohistochemical examination showed that most of the tumor cells were positive for S-100 protein, HMB-45, melan-A, vimentin and CD38. Ultrastructural examination confirmed some premelanosomes. EWS-ATF-1 fusion transcript, which is usually detected in clear cell sarcoma, was not demonstrated on reverse transcriptase-polymerase chain reaction. Because there was no evidence of either cutaneous or ocular primary melanoma, the tumor was thus diagnosed as primary colonic malignant melanoma. The patient has remained free of recurrent disease for 3 years after a surgical resection. Colonic malignant melanoma must be differentiated from other intestinal tumor, and the possibility of metastasis from another more common primary site must be ruled out.
TL;DR: The case of a 58 year old man with clear cell sarcoma of the kidney is reported and the benefit and value of medical imaging for management are discussed.
Abstract: Clear cell sarcoma of the kidney rarely affects adults. It has an aggressive evolution, with a high rate of recurrence and mortality. We report the case of a 58 year old man with clear cell sarcoma of the kidney and discuss the benefit and value of medical imaging for management.
Journal Article•
TL;DR: El mapeo linfatico para identificar ganglio centinela ha demostrado ser util en melanomas y cancer de mama; actualmente se estudia esta tecnica en otro lugar.
Abstract: The procedure of sentinel node biopsy has been used previously in clear cell sarcoma. There are few studies reported. Due to the similar biological features with melanoma, this procedure can be effective. Sentinel biopsy is an option to detect nodal subclinical metastases. A 19-year-old man presented with ulcerated lesion in the fifth finger of the left hand. The biopsy reported clear cell sarcoma. Immunohistochemistry was positive for Vimentin and S-100. There was no evidence of regional disease. The sentinel lymph node biopsy, using patent blue and Tc-99 rhenium, was positive for metastases. Axillar dissection was carried out. The final report confirmed three metastasic nodes and the patient received adjuvant chemotherapy.
TL;DR: A case of clear cell sarcoma (CCS) in which the tumor originated in the S-1 nerve root and had been previously diagnosed as psammomatous melanotic schwannoma (PMS), which supports the hypothesis that biological agents or immunotherapy are potentially important areas of investigation.
Abstract: ✓The authors present a case of clear cell sarcoma (CCS) in which the tumor originated in the S-1 nerve root and had been previously diagnosed as psammomatous melanotic schwannoma (PMS). This is the third case of a spinal nerve root origin for CCS reported in the English-language literature. The similar histogenesis of CCS and malignant melanoma supports the hypothesis that biological agents or immunotherapy are potentially important areas of investigation. The patient underwent S1–3 laminectomy and gross-total resection of the mass lesion. The border of the resection was extended 1 cm distal to the tumor margin. The postoperative period was uneventful. The new histopathological diagnosis was CCS (malignant melanoma of soft tissue). Despite total resection, the patient returned with disseminated disease at the 18-month follow-up visit. His follow-up magnetic resonance image of the lumbar spine revealed sacral L5–S3 involvement of the vertebral bodies along with disseminated cauda equina seeding. A CCS orig...
TL;DR: A case of primary malignant melanoma of the calcaneum in a 68-year-old woman is reported, first described in 1965, which is a very rare bone neoplasm.
Abstract: First described by Enzinger in 1965 primary malignant melanoma (clear cell sarcoma) of bone is a very rare bone neoplasm. We report a case of primary malignant melanoma of the calcaneum in a 68-year-old woman.
TL;DR: Renal tumours in early life are not frequent, and they differ significantly in incidence from those seen later in childhood, so the patient's age may be a very useful clue in reaching an accurate diagnosis of renal tumours, which is critical for administering the most appropriate treatment.
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TL;DR: The UCLA limb-salvage protocol as mentioned in this paper combines preoperative chemotherapy and radiation with a surgical resection that allows a functioning limb to be removed from malignant cells, which may not be resected with the grossly evident disease.
Journal Article•
TL;DR: A case had a checkup for chest bachache with a 21-year-old woman, and it was diagnosed as the right chest wall tumor, and the en bloc resection of parts of the 7th and 8th ribs was performed.
Abstract: Clear cell sarcoma is a rare malignant soft tissue neoplasm that usually arises adjacent to tendons or aponeuroses. The principal sites of this neoplasm are the extremities, but tumors do occur in the trunk on rare occasions. A case had a checkup for chest bachache with a 21-year-old woman, and it was diagnosed as the right chest wall tumor. We performed the en bloc resection of parts of the 7th and 8th ribs. Composix mesh was fixed to cover a deficit in the chest wall. The pathological diagnosis was clear cell sarcoma of the chest wall. The postoperative course was uneventful. She has shown no symptoms or signs of recurrence during 14 months of follow-up.
11 Jul 2006
01 Jan 2006
TL;DR: 23.4.5.5 Malignant Mesenchymoma.
Abstract: 23.4.4.1 Definition . . . . . . . . . . . . . . . . . . . . . 409 23.4.4.2 Incidence and Clinical Behavior . . . . . . . . . 409 23.4.4.3 Imaging . . . . . . . . . . . . . . . . . . . . . . 409 23.4.5 Malignant Mesenchymoma . . . . . . . . . . . 411 23.4.5.1 Definition . . . . . . . . . . . . . . . . . . . . . 411 23.4.5.2 Incidence and Clinical Behavior . . . . . . . . . 412 23.4.5.3 Imaging . . . . . . . . . . . . . . . . . . . . . . 413
31 Oct 2006
TL;DR: 46歳女性。2003年5月に左第1趾の径約1cmの腫瘤を近医内科で切除された;その後同部に再発を認め, 再切 除をした。
Abstract: 46歳女性。2003年5月に左第1趾の径約1cmの腫瘤を近医内科で切除された。その後同部に再発を認め, 再切除をしたが更に同部にびらんを伴う腫瘤が再発し, 2004年5月には径約4cmとなり, 近医外科で再々切除した。病理組織標本でSCCの診断となったため, 精査, 加療目的で当科へ紹介された。皮膚病変部及びFDG-PETで集積を認めた左鼠径リンパ節の摘出標本でHE染色と免疫染色を行った。皮膚病変ではS-100 protein, cytokeratin, vimentinが, 転移リンパ節ではS-100 protein, HMB-45, MART-1, CEA, vimentinが陽性で, 上皮系の悪性腫瘍や悪性黒色腫などが考えられた。転移リンパ節に肉眼的に黒褐色に見える部分があり, 同部位を電顕で観察し, 細胞質内にメラノソームを多数認めたことより, clear cell sarcomaと診断確定した。
TL;DR: CT can precisely delineate the location, size, extent of involvement, imaging characteristics and metastases of renal tumor, which can provide information necessary to the clinical staging, therapy planning and prognosis of the tumors.
Abstract: Objective: To investigate the imaging manifestation of primary malignant renal tumor with CT. Methods: Forty-three cases of surgically and pathologically confirmed primary malignant renal tumor were retrospectively reviewed. Un-contrast and contrast CT was performed in all 43 patients in which 15 patients received MRI examination. Results: The residual normal renal tissue of 29 cases out of 34 cases of Wilms' tumor was enhanced and manifested "crescent sign" or "ring sign". Four cases of malignant rabdoid tumor (RTK) manifested as large mass with notable necrosis and subcapsular fluid collection; Two cases of clear cell sarcoma (CCS) showed metastases to the skull which could indicate the diagnosis; Renal cell carcinoma (RCC) (n=3) showed calcification in 1 case. Conclusion: CT can precisely delineate the location, size, extent of involvement, imaging characteristics and metastases of renal tumor, which can provide information necessary to the clinical staging, therapy planning and prognosis of the tumors.