Clear cell sarcoma of soft parts: report of a case primary in the kidney with cytogenetic confirmation

The current management of clear cell sarcoma

Clear cell sarcoma (CCS) is a rare melanocytic soft tissue sarcoma with a high propensity for lymphatic metastasis and poor prognosis. It is characterized by the translocation of t (12;22), resulting in the rearrangement of the EWSR1 gene and overexpression of MET. Despite improvements in the diagnosis and treatment of soft tissue sarcomas, the management of CCSs remains challenging owing to their rarity, unique biological behaviour and limited understanding of their molecular pathogenesis. The standard treatment for localized CCSs is surgical excision with negative margins. However, there is an ongoing debate regarding the role of adjuvant chemotherapy, radiotherapy and lymphadenectomy in the management of this disease. CCSs are usually resistant to conventional chemotherapy. Targeted therapies, such as sunitinib and MET inhibitors, may provide promising results. Immunotherapy, particularly immune checkpoint inhibitors, is currently under investigation as a potential treatment option for CCSs. Further research is needed to better understand the biology of CCSs and develop effective therapeutic strategies. The purpose of this review is to provide a comprehensive overview of current knowledge and advances in the diagnosis and treatment of CCSs.

Novel MEIS1-NCOA2 Gene Fusions Define a Distinct Primitive Spindle Cell Sarcoma of the Kidney

We describe 2 cases of a distinct sarcoma characterized by a novel MEIS1-NCOA2 gene fusion. This gene fusion was identified in the renal neoplasms of 2 adults (21-y-old male, 72-y-old female). Histologically, the resected renal neoplasms had a distinctively nodular appearance, and while one renal neoplasm was predominantly cystic, the other demonstrated solid architecture, invasion of perirenal fat, and renal sinus vasculature invasion. The neoplasms were characterized predominantly by monomorphic plump spindle cells arranged in vague fascicles with a whorling pattern; however, a more primitive small round cell component was also noted. Both neoplasms were mitotically active and one case showed necrosis. The neoplasms did not have a distinctive immunohistochemical profile, though both labeled for TLE1. The morphologic features are distinct from other sarcomas associated with NCOA2 gene fusions, including mesenchymal chondrosarcoma, congenital/infantile spindle cell rhabdomyosarcoma, and soft tissue angiofibroma. While we have minimal clinical follow-up, the aggressive histologic features of these neoplasms indicate malignant potential, thus warranting classification as a novel subtype of sarcoma.

Giant solitary fibrous tumor of the pleura with high-grade sarcomatous overgrowth accompanied by lipid-rich, rhabdomyosarcomatous, and pleomorphic components: A case report

RATIONALE

Solitary fibrous tumors are mesenchymal tumors presenting as fibroblastic neoplasms with prominent branching vascular patterns, which are often generated from the pleura. Most solitary fibrous tumors are benign; however, some can turn malignant. High-grade sarcomas from solitary fibrous tumors include multidirectional histopathological components.

PATIENT CONCERNS

We describe our experience of a giant high-grade sarcoma with mixed components generated from a solitary fibrous tumor of the pleura in a 67-year-old female patient presenting with cough and left-sided chest pain. The patient had been diagnosed with a pleural mass in the left chest by X-ray about 30 years earlier. However, the tumor was allowed to grow, without surgical intervention, for a long time.

INTERVENTIONS

Thoracic surgeons performed the removal of the giant pleural tumor; the tumor measured 18.0 × 14.5 × 10 cm in size, and was considered a giant tumor generated from the pleura of the left chest cavity.

DIAGNOSES

The surgically removed tumor was solid and light brownish, and included myxoid and arabesque pattern lesions. The tumor also showed hemorrhagic and necrotic lesions. Moreover, spindle cells with less atypia, resembling fibroblasts, were noted. These spindle tumor cells were CD34- and Stat6-positive, suggesting a solitary fibrous tumor. Some of the spindle tumor cells were surrounded by thick collagenous fibers. Considering that the tumor originated from the parietal pleura, the tumor was defined as a solitary fibrous tumor in origin. The tumor also comprised high-grade sarcomatous components; these included lipid-rich, rhabdomyosarcomatous, and pleomorphic components. The high-grade sarcoma component included bizarre tumor cells with severe atypia.

OUTCOMES

Tumor recurrence occurred in the left chest about 4 months after the surgery, and the patient died 8 months postoperatively.

LESSONS

The present case clearly demonstrates that a solitary fibrous tumor can develop into high-grade sarcomatous overgrowth, including lipid-rich, rhabdomyosarcoma, and pleomorphic sarcoma components, if left untreated for a prolonged period. This case provides profound insights about the natural history, histogenesis, differentiation, and malignant transformation of solitary fibrous tumors.

Hepatic falciform ligament clear cell myomelanocytic tumor: A case report and a comprehensive review of the literature on perivascular epithelioid cell tumors

Background

The objective of the study was to explore the clinical expression, radiological and pathological features, differential diagnosis, and biological behavior of a clear cell myomelanocytic tumor. In a case involving a clear cell myomelanocytic tumor located in the hepatic falciform ligament, we evaluated clinical expression, radiological characteristics, histopathology, immunohistochemistry, and biological behavior; we also reviewed the relevant literature.

Case presentation

Clear cell myomelanocytic tumor is a benign soft-tissue neoplasm that often occurs in women, and is expressed as a painless mass. The falciform ligament is its most frequent site of occurrence. The imaging characteristics of this lesion were uneven enhancement in the arterial phase, continuing to strengthen in the venous phase, and equal density in the balance phase. Histological and immunohistochemical analysis revealed the main transparent epithelioid cells and smooth muscle spindle cells to be HMB-45(+), smooth muscle actin(+), and melan-A (+).

Conclusion

Hepatic vascular epithelioid cell tumors are very rare mesenchymal neoplasms. Few studies have investigated this tumor in the hepatic falciform ligament; consequently, its diagnosis and the selection of an appropriate treatment and follow-up protocol are challenging. Treatment outcome remains unpredictable. Therefore, clear cell myomelanocytic tumor should be viewed as a tumor with uncertain malignant potential requiring long-term follow-up.

Primary renal sclerosing epithelioid fibrosarcoma: report of 2 cases with EWSR1-CREB3L1 gene fusion

We report the first 2 genetically confirmed cases of primary renal sclerosing epithelioid fibrosarcoma (SEF), occurring in a 17-year-old boy and a 61-year-old woman. In both cases, the tumors demonstrated the typical epithelioid clear cell morphology associated with extensive hyalinizing fibrosis, raising the differential diagnosis of solitary fibrous tumor, metanephric stromal tumor, and the sclerosing variant of clear cell sarcoma of the kidney. Both neoplasms demonstrated diffuse immunoreactivity for MUC4, a highly specific marker for SEF, and both demonstrated evidence of rearrangement of both the EWSR1 and CREB3L1 genes, which have recently been shown to be fused in this entity. Both neoplasms presented with metastatic disease. Primary renal SEF represents yet another translocation-associated sarcoma now shown to arise primarily in the kidney.

Non-antiepileptic drugs for trigeminal neuralgia

BACKGROUND

Trigeminal neuralgia was defined by the International Association for the Study of Pain as a sudden, usually unilateral, severe, brief, stabbing recurrent pain in the distribution of one or more branches of the fifth cranial nerve. Standard treatment is with anti-epileptic drugs. Non-antiepileptic drugs have been used in the management of trigeminal neuralgia since the 1970s. This is an update of a review first published in 2006 and previously updated in 2011.

OBJECTIVES

To systematically review the efficacy and tolerability of non-antiepileptic drugs for trigeminal neuralgia.

SEARCH METHODS

On 20 May 2013, for this updated review, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (2013, Issue 4), MEDLINE (January 1966 to May 2013), EMBASE (January 1980 to May 2013), LILACS (January 1982 to May 2013) and the Chinese Biomedical Retrieval System (1978 to May 2013). We searched clinical trials registries for ongoing trials.

SELECTION CRITERIA

We included double-blind, randomised controlled trials in which the active drug was used either alone or in combination with other non-antiepileptic drugs for at least two weeks.

DATA COLLECTION AND ANALYSIS

Two authors decided which trials fitted the inclusion criteria and independently graded risk of bias. We assessed the quality of the evidence according to the GRADE criteria for this update.

MAIN RESULTS

In this 2013 update, we updated the searches, but identified only two new ongoing studies. The review includes four trials involving 139 participants. The primary outcome measure in each was pain relief. Three trials compared one of the oral non-antiepileptic drugs tizanidine, tocainide or pimozide with carbamazepine. The quality of evidence for all outcomes for which data were available was low. In a trial of tizanidine involving 12 participants (one dropped out due to unrelated disease), one of five participants treated with tizanidine and four of six treated with carbamazepine improved (risk ratio (RR) 0.30, 95% confidence interval (CI) 0.05 to 1.89). Few side effects were noted with tizanidine. For pimozide, there was evidence of greater efficacy than carbamazepine at six weeks. Up to 83% of participants reported adverse effects but these did not lead to withdrawal; the report did not provide comparable data for carbamazepine. Limited data meant that we could not assess the effects of tocainide; however, data from non-randomised studies (not included in this review) indicate that serious haematological adverse events can occur. A trial involving 47 participants compared 0.5% proparacaine hydrochloride eyedrops with placebo but did not show any significant benefits, again according to low-quality evidence. The report did not mention adverse events. The proparacaine trial was at low risk of bias; the other trials were at unclear risk of bias overall.

AUTHORS' CONCLUSIONS

There is low-quality evidence that the effect of tizanidine is not significantly different than that of carbamazepine in treating trigeminal neuralgia. Pimozide is more effective than carbamazepine, although the evidence is of low quality and the data did not allow comparison of adverse event rates. There is also low-quality evidence that 0.5% proparacaine hydrochloride eye drops have no benefit over placebo. Limitations in the data for tocainide prevent any conclusions being drawn. There is insufficient evidence from randomised controlled trials to show significant benefit from non-antiepileptic drugs in trigeminal neuralgia. More research is needed.

Clear-cell sarcoma of the soft tissue--a rare diagnosis with a fatal outcome

Clear-cell sarcomas account for less than 1% of all soft tissue tumours. They most often occur in middle-aged adults as a deeply located lesion with predilection to the tendons and aponeuroses. The aim of the present study was to show possible influencing factors on the outcome after surgical treatment in a detailed case series. We reviewed the medical records of 11 patients with the diagnosis of a clear-cell sarcoma of the soft tissue. These cases were analysed with regard to age, gender, localisation, tumour size, recurrence free survival and overall survival. A minimum follow up of 12 months was achieved. The mean age at the point of diagnosis was 47.9 years. Metastases occurred after a mean of 19.2 months. In the cases with a tumour diameter >5 cm, metastases occurred earlier. When treated in a specialist centre, metastases occurred later. Patients died a mean of 18.4 months after developing metastatic disease. Patients with tumour size >5 cm at the point of primary diagnosis died earlier than patients with a tumour size <5 cm. It is important to detect clear-cell sarcomas as soon as possible and the final surgical treatment should be performed in a centre familiar with the treatment of soft tissue tumours not only to prolong overall survival, but also to treat the patient in a multiprofessional team.

Intra-abdominal clear-cell sarcoma: a report of 3 cases, including 1 case with unusual morphological features, and review of the literature

Clear-cell sarcoma (CCS) is a soft-tissue neoplasm that morphologically resembles cutaneous malignant melanoma but has a distinct molecular profile. Gastrointestinal and intra-abdominal CCSs are very rare. Here, the authors present 3 cases of intra-abdominal CCS and review the literature. Of these cases, 2 involved the small bowel, and 1 involved the peritoneum. Cases 1 and 3 had the characteristic CCS morphology, but case 2 was morphologically unusual and therefore difficult to diagnose. It had relatively small cells with less prominence of clear cells; many pseudoglandular structures were also present. It also showed aberrant expression of epithelial membrane antigen (EMA). The other 2 cases also involved some diagnostic uncertainty and were therefore referred to specialized centers. The authors wish to emphasize the importance of molecular studies in making a conclusive diagnosis of intra-abdominal CCS.

Clear Cell Tumors of Soft Tissue

Clear cell lesions of soft tissue include varying morphologic patterns and a range of clinical behaviors and prognoses. Benign lesions include perivascular epithelioid cell tumors, clear cell fibrous papule, and distinctive dermal clear cell mesenchymal tumor; malignant tumors include clear cell sarcoma, liposarcoma, and rare malignant perivascular epithelioid cell tumors. Clear cell variants of other benign and malignant soft tissue tumors include fibrous histiocytoma, atypical fibroxanthoma, myoepithelioma, leiomyoma and leiomyosarcoma, and rhabdomyosarcoma. Metastatic clear cell tumors, including renal cell carcinoma and adrenal cortical carcinoma, should be considered in the differential diagnosis and excluded through clinical history, imaging studies, and immunohistochemical stains.

Primary clear cell sarcoma of the sacrum: a case report

Clear cell sarcoma, first described by Enzinger in 1965, is an uncommon malignant soft tissue neoplasm that displays melanocytic differentiation. It occurs predominantly in the soft tissue of the extremities in young adults or children. Primary clear cell sarcoma of the bone is extremely rare, only seven cases have been reported to our knowledge. We present here a case of a huge primary clear cell sarcoma of the sacrum arising in a 25-year-old man. The average percentage of melanin content in the tumor was 9.25 ± 6.71%, which resulted in hypointense signal in T2-weighted and heterogeneous hyperintense signal in T1-wieghted images of magnetic resonance imaging (MRI). The patient was treated with curettage of the mass and neither further radiotherapy nor chemotherapy had been provided. The patient had local regrowth of tumor at 9 months after surgery. To our knowledge, this is the first case of CCS in the axial skeleton documented in English literature.

Clear cell sarcoma of tendons and aponeuroses, and osteoclast-rich tumour of the gastrointestinal tract with features resembling clear cell sarcoma of soft parts: a review and update

Clear cell sarcoma (CCS) is a rare, distinctive soft tissue neoplasm, typically occurring in the distal extremities of young adult patients. Although CCS shows melanocytic differentiation, it is now clear that it is clinicopathologically and genetically distinct from conventional malignant melanoma. The 'osteoclast-rich tumour of the gastrointestinal tract with features resembling clear cell sarcoma of soft parts' is an extraordinarily rare gastrointestinal neoplasm that shares some features of CCS, but differs from it in other ways. The historical, histopathological, ultrastructural, immunohistochemical and genetic aspects of these two tumours are reviewed in this article.

Melanotic Xp11 translocation renal cancers: a distinctive neoplasm with overlapping features of PEComa, carcinoma, and melanoma

We describe 2 cases of malignant melanotic epithelioid renal neoplasms bearing TFE3 gene fusions. Both neoplasms occurred in children (an 11-y-old boy and a 12-y-old girl), and presented with disseminated metastatic disease including mediastinal and mesenteric adenopathy. Both neoplasms featured sheets of epithelioid cells with clear to finely granular eosinophilic cytoplasm set in a branching capillary vasculature. The neoplastic cells contained variable amounts of finely brown pigment confirmed to be melanin by histochemical stains. By immunohistochemistry, the neoplastic cells labeled for melanocytic markers HMB45 and Melan A, but not for S100 protein, MiTF, or any epithelial marker (cytokeratins, epithelial membrane antigen), renal tubular marker (CD10, PAX8, PAX2, RCC Marker) or muscle marker (actin, desmin). Both neoplasms demonstrated nuclear labeling for TFE3 protein by immunohistochemistry, and the presence of TFE3 gene fusions was confirmed by TFE3 fluorescence in situ hybridization analysis. These distinctive neoplasms combine morphologic features of perivascular epithelioid cell neoplasms (PEComas), Xp11 translocation carcinoma, and melanoma, though the phenotype most closely approaches PEComa. These neoplasms represent the first documented examples in which TFE3 gene fusions coexist with melanin production, and their identification raises the possibility that TFE3 gene fusions may underlie an aggressive subset of lesions currently classified as PEComa in young patients.

Gastrointestinal melanoma or clear cell sarcoma? Molecular evaluation of 7 cases previously diagnosed as malignant melanoma

Clear cell sarcoma (CCS) is a rare tumor classically associated with the tendons and aponeuroses of distal extremities of young adults. CCS and malignant melanoma (MM) share immunohistochemical profiles and ultrastructural features, but classic CCS has characteristic morphology with low mitotic activity and minimal pleomorphism. Occasional cases show pleomorphism, high mitotic index, and/or melanin pigmentation, making CCS indistinguishable from MM based on morphology. However, CCS is genetically distinct owing to its consistent association with a t(12;22)(q13;q12) chromosomal translocation, leading to the formation of the EWS/ATF1 fusion transcript. This translocation has never been documented in cutaneous melanoma, and thus is regarded as specific for CCS. Recent evidence suggests that primary "malignant melanomas" in unusual anatomic sites, most notably the gastrointestinal (GI) tract, may be CCS. This is supported by 11 cases of primary GI CCS with the t(12;22) translocation. We used reverse-transcription polymerase chain reaction and fluorescence in situ hybridization to examine whether a proportion of cases diagnosed as MM of the GI tract in patients without a history of cutaneous MM actually represent primary GI CCS. In total, we examined 7 cases: Four with no prior history of MM, 2 with histories of cutaneous MM, and 1 with an anal MM. All 4 cases for which there was no history of cutaneous/mucosal MM harbored the EWS/ATF1 fusion transcript. We report the largest series of GI CCS and have shown that molecular studies may be warranted in cases that otherwise seem to represent MM of unusual primary locations.

Clear cell sarcoma of the ileum: report of a case and review of literature

Clear cell sarcoma (CCS) is a high grade soft tissue sarcoma with a distinct molecular profile and with morphological features resembling those of melanoma. CCS has been rarely described in other locations other than the soft tissues, including the gastrointestinal tract. In this study, we report a case of CCS arising in the ileum of a 31-year-old woman. Histologically, the tumor involved the entire thickness of the intestinal wall. Tumor cells were polygonal or fusiform, with clear or eosinophilic cytoplasm, arranged in a uniform nested to fascicular growth pattern. Immunohistochemical studies revealed strong positivity for vimentin and S-100 protein. HMB-45, Melan-A, tyrosinase, cytokeratins, EMA, smooth muscle actin, CD34, CD31, CD117, CD99, synaptophysin, chromogranin A, CD56, and NSE were negative. Fluorescence in situ hybridization analysis demonstrated the presence of a t(12;22)(q13;q12) translocation, the diagnostic hallmark of CCS of soft parts. The present case, together with a detailed review of the literature on this topic, demonstrates that the gastrointestinal tract is a possible site of CCS of soft tissues and that making a reliable diagnosis of this tumor requires cytogenetic or molecular diagnostic investigations.

Primary colonic malignant melanoma

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.

Myxoid clear cell sarcoma

Clear cell sarcoma is a rare soft-tissue tumor presenting typically in the extremities of young adults. It has been also known as malignant melanoma of the soft parts because of the presence of melanin and cytoplasmic melanosomes. However, clear cell sarcoma is, at present, usually considered as a unique lesion because the t(12;22)(q13;q12) translocation is present only in clear cell sarcoma. Myxoid malignant melanoma is now a well-recognized morphologic variant of malignant melanoma. However, a myxoid variant of clear cell sarcoma has not been well described yet. We report a case of myxoid clear cell sarcoma occurring on the heel in a 22-year-old man. The tumor was composed of nests and fascicles of oval to fusiform cells with clear to pale eosinophilic cytoplasm, often separated by fibrous septa. The tumor cells were reactive for S-100 protein, HMB-45, and MART-1. Variably sized cysts lined by one or several layers of tumor cells were observed. Alcian blue and mucicarmine stains demonstrated prominent mucin deposition in the tumor stroma and especially in the lumen of the cysts. Fluorescence in situ hybridization for the Ewing sarcoma gene showed rearrangement in nearly all of the neoplastic cells.

EWS-ATF1 fusion transcripts in gastrointestinal tumors previously diagnosed as malignant melanoma

BACKGROUND

Clear cell sarcoma (CCS) is classically a deep soft tissue tumor associated with tendons or aponeuroses, although cases of primary CCS of the gastrointestinal (GI) tract have recently been reported. Because it is difficult to distinguish CCS from metastatic melanoma based on morphology, immunohistochemical profile, and ultrastructural features, it is possible that some GI tumors diagnosed as metastatic melanoma actually represent primary GI CCS. Because the EWS-ATF1 fusion transcript and the associated t(12;22)(q13;q12) translocation occur in CCS but not cutaneous melanoma, we investigated the use of molecular-based testing for discriminating CCS from metastatic melanoma (MM) in GI tumors.

METHODS

Patients with GI tumors diagnosed as MM were identified from departmental files. The tumors were tested for the EWS-ATF1 fusion transcript by RT-PCR and for t(12;22)(q13;q12) by fluorescence in situ hybridization.

RESULTS

Detailed review of medical records revealed that 16 (80%) of the 20 had a documented history of cutaneous melanoma. Two cases (10%) harbored the EWS-ATF1 fusion transcript, and fluorescence in situ hybridization confirmed the presence of t(12;22) in both cases. Of the 2 positive tumors, 1 developed in a patient who had no history of cutaneous melanoma, and the other developed in a patient with a remote history of vulvar melanoma.

CONCLUSION

Based on molecular genetic findings, a subset of GI tumors diagnosed as MM by routine histopathologic evaluation represents CCS.

Primary clear cell sarcoma of bone

Clear cell sarcoma is a rare soft tissue sarcoma of young adults with melanocytic differentiation. It occurs predominantly in the soft tissue of extremities, typically involving tendons and aponeuroses. Primary clear cell sarcoma of bone is extremely rare. We report a case of primary clear cell sarcoma of the right first metatarsal in a 48-year-old woman and provide a literature review of the entity.

Karyotypic divergence and convergence in two synchronous lung metastases of a clear cell sarcoma of tendons and aponeuroses with t(12;22)(q13;q12) and type 1 EWS/ATF1

Clear cell sarcoma of tendons and aponeuroses (CCS) is an uncommon malignancy characterized by a t(12;22)(q13;q12) causing a fusion of the EWS and ATF1 genes. We describe the cytogenetic and molecular genetic analyses of two lung metastases from a CCS patient. Both lesions presented the defining t(12;22) and a type 1 EWS/ATF1 chimeric transcript. The additional cytogenetic changes present in the two lesions allowed us to obtain some insight into the pathogenetic basis of disease progression. Four related clones were identified in the right lung metastasis, permitting a partial reconstitution of the stepwise clonal evolution, whereas the left lung metastasis presented yet another subclone. The comparison of the two karyotypes enabled us to pinpoint which changes occurred in the primary tumor and which emerged independently after the two metastases had been established. We conclude that both clonal divergence and convergence may be operative during tumor progression of CCS.

An osteoclast-rich tumor of the gastrointestinal tract with features resembling clear cell sarcoma of soft parts: reports of 6 cases of a GIST simulator

Six cases are reported of an osteoclast-rich tumor of the gastrointestinal tract that should be segregated from GIST. Five of the cases were located in the small bowel and one in the stomach. The age of the patients ranged from 13 to 37 years. The tumors behaved aggressively, with metastases to regional lymph nodes, liver, and other intra-abdominal sites. Microscopically, the tumor cells were medium-sized, predominantly oval, relatively monomorphic, diffusely immunoreactive for S-100-protein, and negative for CD117, CD34, HMB-45, and Mart-1. They were admixed with scattered osteoclast-like, multinucleated giant cells which were S-100-protein negative and KP1-positive. One case studied cytogenetically had the karyotype 46XX t(12;22)(q13;q12). The cases here reported are interpreted as examples of a distinctive type of gastrointestinal neoplasm which shares some features with clear cell sarcoma of soft parts (melanoma of soft parts), including in one case the chromosomal translocation that is characteristically associated with that entity.

Clear cell sarcoma of tendons and aponeuroses in pediatric patients: a report from the Italian and German Soft Tissue Sarcoma Cooperative Group

BACKGROUND

Clear cell sarcoma (CCS) of tendons and aponeuroses is extremely rare in childhood and little information is available on its clinical management. Originally believed to be a type of melanoma of soft tissue origin, CCS is now considered a distinct clinicopathologic entity that behaves like a high-grade soft tissue sarcoma. We report on a series of 28 pediatric patients treated from 1980 to 2000 by the Soft Tissue Sarcoma Italian Cooperative Group and the German Cooperative Group.

METHODS

Patients were treated with a multimodality therapeutic approach. Surgical resection was complete in 17 patients (mutilating in 3), radiotherapy was administered to 8 patients, and 20 patients received chemotherapy.

RESULTS

After a median follow-up of 102 months (range, 19-238 months), the 5-year and event-free survival rates were 66.4% and 63.3%, respectively. Seventeen patients were alive in first remission, two were alive in second remission, and nine had died of disease. The response to chemotherapy in the 7 evaluable patients included one partial remission, one minor response, and five no responses. Radiotherapy contributed to achieving local control in four of six Intergroup Rhabdomyosarcoma Study (IRS) Group II patients. Statistically significant differences in outcome were evident according to IRS group, tumor size, and site.

CONCLUSIONS

Our study confirms the aggressive behavior of CCS. Complete surgical resection represents the mainstay of treatment, and even the only treatment for patients with small tumors. Radiotherapy may control microscopic residual disease after surgery. Chemotherapy is ineffective and the prognosis is unfavorable for patients with unresectable and large tumors.

Clear cell myomelanocytic tumor of the thigh: report of a unique case

The clear cell myomelanocytic tumor (CCMMT) is a recently reported and very rare member of the perivascular epithelioid cell family of tumors (PEComa). All CCMMTs reported to date have occurred in or immediately adjacent to the falciform ligament/ligamentum teres. We report a case of CCMMT that occurred in the right thigh of a 43-year-old woman. Histologic examination showed the classic features of CCMMT, and immunohistochemical studies confirmed co-expression of smooth muscle actin, HMB-45, and microphthalmia transcription factor.

Clear-cell sarcoma diagnosis by fine-needle aspiration: cytologic, histologic, and ultrastructural features; potential pitfalls; and literature review

A definitive diagnosis of clear-cell sarcoma of soft parts (CCSSP) is possible by fine-needle aspiration (FNA) biopsy alone. The aspirates are markedly cellular, consisting predominantly of discohesive cells but also of cohesive cells. The cytoplasm is eosinophilic and eccentric. The nuclei are round and contain macronucleoli. CCSSP should be considered when FNA of a soft-tissue tumor shows uncharacteristically high cellularity and relatively uniform cells with macronucleoli. Cohesion of some tumor cells does not rule out CCSSP. Melanin pigment and cytoplasmic clearing are infrequent and not necessary for the diagnosis. Sufficient material should always be procured for immunohistochemical studies on the cell block. Seven other cases are found in the literature, all correctly diagnosed by FNA. Although it is rare, CCSSP is a highly malignant tumor that can be diagnosed readily by FNA without resorting to incisional biopsy.

Primary renal neoplasms with the ASPL-TFE3 gene fusion of alveolar soft part sarcoma: a distinctive tumor entity previously included among renal cell carcinomas of children and adolescents

The unbalanced translocation, der(17)t(X;17)(p11.2;q25), is characteristic of alveolar soft part sarcoma (ASPS). We have recently shown that this translocation fuses the TFE3 transcription factor gene at Xp11.2 to ASPL, a novel gene at 17q25. We describe herein eight morphologically distinctive renal tumors occurring in young people that bear the identical ASPL-TFE3 fusion transcript as ASPS, with the distinction that the t(X;17) translocation is cytogenetically balanced in these renal tumors. A relationship between these renal tumors and ASPS was initially suggested by the cytogenetic finding of a balanced t(X;17)(p11.2;q25) in two of the cases, and the ASPL-TFE3 fusion transcripts were then confirmed by reverse transcriptase-polymerase chain reaction. The morphology of these eight ASPL-TFE3 fusion-positive renal tumors, although overlapping in some aspects that of classic ASPS, more closely resembles renal cell carcinoma (RCC), which was the a priori diagnosis in all cases. These tumors demonstrate nested and pseudopapillary patterns of growth, psammomatous calcifications, and epithelioid cells with abundant clear cytoplasm and well-defined cell borders. By immunohistochemistry, four tumors were negative for all epithelial markers tested, whereas four were focally positive for cytokeratin and two were reactive for epithelial membrane antigen (EMA) (one diffusely, one focally). Electron microscopy of six tumors demonstrated a combination of ASPS-like features (dense granules in four cases, rhomboid crystals in two cases) and epithelial features (cell junctions in six cases, microvilli and true glandular lumens in three cases). Overall, although seven of eight tumors demonstrated at least focal epithelial features by electron microscopy or immunohistochemistry, the degree and extent of epithelial differentiation was notably less than expected for typical RCC. We confirmed the balanced nature of the t(X;17) translocation by fluorescence in situ hybridization in all seven renal tumors thus analyzed, which contrasts sharply with the unbalanced nature of the translocation in ASPS. In summary, a subset of tumors previously considered to be RCC in young people are in fact genetically related to ASPS, although their distinctive morphological and genetic features justify their classification as a distinctive neoplastic entity. Finally, the finding of distinctive tumors being associated with balanced and unbalanced forms of the same translocation is to our knowledge, unprecedented.

Clear cell variant of malignant melanoma of the uterine cervix: a case report and review of the literature

BACKGROUND

A rare variant of malignant melanoma of the uterine cervix mimicking clear cell carcinoma or clear cell sarcoma is described.

CASE

A 33-year-old Japanese woman was admitted to the hospital complaining of genital discharge and lower back pain. The stage was FIGO IIB and radical hysterectomy and pelvic lymphadenectomy were done. Pathological examination, immunohistochemical studies of melanin granules, and molecular analysis of the EWS/ATF-1 fusion gene were also done. A diffuse proliferation of amelanotic clear cells was detected in the uterine cervix. Tumor cells were positive for HMB 45, Melan-A (MART-1), and S-100 protein and negative for epithelial markers. The EWS/ATF-1 fusion gene was not detected.

CONCLUSION

This is apparently the first report of a case of clear cell melanoma of the uterine cervix. Despite its rarity, this variant of malignant melanoma should be considered when diagnosing clear cell neoplasms of the uterine cervix.

Isochromosome 7q in adult Wilms' tumors: diagnostic and pathogenetic implications

Wilms' tumors affecting adults are rare and are thought to have a worse prognosis than similar stage tumors in the pediatric population. To understand these tumors better, the authors reviewed their multi-institutional experience in a series of nine lesions diagnosed as Wilms' tumors in adults. In addition to histologic and immunohistochemical examination, they performed cytogenetic analysis and fluorescence in situ hybridization. On review, four cases were reclassified: two "blastema only" as Ewing's sarcoma/primitive neuroectodermal tumor and the other two as clear cell sarcoma of soft parts and sarcoma not otherwise specified (NOS). Of the remaining five cases, three exhibited biphasic histology and two were triphasic. In this group, there were three women and two men, and patient age ranged from 17 to 37 years (median age, 26 years). Tumor size was large and ranged from 10 to 31 cm (median tumor size, 12.5 cm). Histologically, the tumors showed the typical features of Wilms' tumors with varying amounts of blastema (n = 5), epithelium (n = 5), and stroma (n = 2). No tumors contained anaplasia, and persistent renal blastema was not identified in the non-neoplastic kidney in any specimen. All tumors were positive for cytokeratins (CK7, n = 3; pankeratin, n = 5), and one tumor was weakly positive for CD99 (0-13). Molecular analysis including dual color fluorescence in situ hybridization (all tumors), and cytogenetic analysis (n = 2) disclosed the presence of isochromosome 7q in three of five tumors whereas all tumors were diploid with respect to chromosome 12. Follow-up data ranged from 6 to 133 months (median follow-up, 82 months) with progression in only one patient who had stage IV disease with lymph node and lung metastases at presentation. The authors conclude that adult Wilms' tumor has been overdiagnosed. Most "blastema-only" tumors in adults are not Wilms' tumors, and in an adult, biphasic morphology should be the minimum criteria for their diagnosis. Using strict diagnostic criteria, adult Wilms' tumors have a relatively favorable prognosis. The characteristic findings of isochromosome 7q, lack of trisomy or tetrasomy for chromosome 12, and absence of persistent renal blastema suggest that the pathogenesis of Wilms' tumors in adults may be different than in the pediatric population. These genetic features may be helpful in distinguishing adult Wilms' tumors from other primary renal tumors.

Clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres: a novel member of the perivascular epithelioid clear cell family of tumors with a predilection for children and young adults

The perivascular epithelioid cell family of tumors (PEComas), defined by their co-expression of melanocytic and muscle markers, includes angiomyolipoma, lymphangioleiomyoma, and clear cell "sugar" tumors of the lung, pancreas, and uterus. We present seven cases of a unique and previously unrecognized tumor of children and young adults, which represents a new addition to the PEComa group of tumors. Culled from three institutions over a 50-year period, all cases occurred in or immediately adjacent to the ligamentum teres and falciform ligament. Six patients were female and one male; their ages ranged from 3 to 21 years (median, 11 yrs). Tumor sizes ranged from 5 to 20 cm (median, 8 cm). All cases consisted of clear to faintly eosinophilic spindled cells arranged in fascicular and nested patterns. The cells had small but distinct nucleoli and low mitotic activity. Immunohistochemically, all cases were positive with antibodies to gp100 protein (HMB-45) and negative for S-100 protein. In three of the seven cases studied immunohistochemically, the tumors expressed smooth muscle actin, melan-A, microphthalmia transcription factor (MiTF), and myosin, but not desmin. No expression of the TSC2 gene product, tuberin, was seen in three cases. One case studied cytogenetically disclosed a t(3;10). Follow-up data, available in six of seven cases (median duration, 18 mos), showed five patients to be free of disease and one to have a radiographically presumed lung metastasis. We think these tumors comprise a new entity for which we propose the term "clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres." The differential diagnosis of these tumors includes clear cell sarcoma of tendons and aponeuroses, leiomyosarcoma, and angiomyolipoma.

Primary renal synovial sarcoma: molecular and morphologic delineation of an entity previously included among embryonal sarcomas of the kidney

We report 15 primary renal neoplasms with morphologic, immunohistochemical, and molecular features identical to those of synovial sarcoma. These tumors form a distinct subset of the entity previously designated as embryonal sarcoma of the kidney. Most were diagnosed between the ages of 20 and 50 years. On gross examination, tumors are large, partially necrotic, and usually contain smooth-walled cysts. Microscopically, tumors are characterized by mitotically active, monomorphic plump spindle cells with indistinct cell borders growing in short, intersecting fascicles. Grossly identified cysts are lined by mitotically inactive polygonal eosinophilic cells with apically oriented nuclei ("hobnailed epithelium"). The spindle cells are immunoreactive for vimentin, often immunoreactive for EMA, but typically non-immunoreactive for desmin, actin, S100, or cytokeratins, whereas the cyst epithelium is cytokeratin-positive. These findings are consistent with monophasic, spindled synovial sarcoma encircling dilated native renal collecting ducts. The presence of an SYT-SSX gene fusion resulting from the t(X;18) characteristic of synovial sarcoma was demonstrated by reverse transcriptase polymerase chain reaction in three of three tumors in which adequate RNA could be obtained from paraffin blocks. An additional case demonstrated the characteristic t(X; 18) translocation on cytogenetic analysis, but adequate material to perform molecular studies was not available in this case or the remaining 11 cases. Primary renal synovial sarcoma is a distinctive clinicopathologic entity confirmed by molecular detection of SYT-SSX fusion transcripts.

Cytogenetics and the biologic basis of sarcomas

In this past year, a large number of reports have described cytogenetic and biologic studies of sarcomas. The cytogenetic studies provide further evidence that a growing number of sarcomas seem to be defined by consistent chromosomal abnormalities that can be detected using a variety of molecular genetic tests. However, in addition to these specific abnormalities, many sarcomas have other extremely complex genetic changes. This complexity has made it quite difficult to understand the importance of any single abnormality. Laboratory studies complementing these genetic studies have provided further understanding of sarcoma cellular and molecular biology. Importantly, both types of studies have had significant impact in the clinic in the form of more objective diagnostic tests, potential novel prognostic markers, and even new therapeutic strategies. Together, these papers highlight how genetic studies may offer tremendous insight into sarcoma biology. However, they also highlight some limitations of these approaches as well. Novel experimental approaches may be required to facilitate the continued progress in this field toward the development of better therapeutic strategies.

Clear cell sarcoma arising in the transverse colon

A case of clear cell sarcoma (CCS) arising in the transverse colon is presented. The tumor consisted of sheets or small nests of epithelioid malignant cells possessing pleomorphic nuclei with one or more prominent nucleoli and ample clear or slightly eosinophilic cytoplasm. Some of the tumor cells contained various amounts of melanin pigments that were confirmed by histochemical and ultrastructural examinations. Immunohistochemical examination showed a positive immunoreactivity for HMB45 and S-100 protein. A metastatic nodule, which was found 9 months after surgery, showed similar histological findings to those of the primary one but lacked melanin pigments. Reverse transcriptase- polymerase chain reaction using total ribonucleic acid obtained from metastatic nodule demonstrated the presence of EWS-ATF-1 fusion gene. Based on these findings, the present case tumor is a CCS of the colon.