原文摘要

Hantschke M, Mentzel T, Rütten A, et al. Cutaneous clear cell sarcoma: a clinicopathologic, immunohistochemical, and molecular analysis of 12 cases emphasizing its distinction from dermal melanoma. Am J Surg Pathol. 2010;34:216-22.

Clear cell sarcoma (CCS) of tendons and aponeuroses/malignant melanoma (MM) of soft parts is a rare tumor and in the majority of cases presents a characteristic reciprocal translocation t(12;22)(q13;q12) that results in fusion of the EWS and ATF1 genes. Although the melanocytic differentiation of CCS is indisputable, its precise lineage remains unclear. Typically, the slowly growing tumor affects the extremities of adolescents or young adults, especially around the ankle and foot.CCS is classically regarded as a deep soft tissue tumor associated with tendons or aponeuroses. This traditional view is put into perspective by the description

of primary CCS of the gastrointestinal tract that may have a variant fusion gene EWSR1-CREB1. We describe 12 cases of cutaneous CCS and discuss the differential diagnoses. These 12 cases share an identical immunohistochemical profile with MM and thus can easily be confused with a dermal variant of spindle cell MM or metastasis of MM. The patients' ages ranged from 6 to 74 years (median: 25 y),

and there was a female predominance (10 females, 2 males). Most tumors (n = 9) were located on the extremities, 2 tumors arose on the back, and 1 on the abdomen. The mean tumor size was 0.97 cm (range, 0.4 to 1.7 cm). Six cases showed invasion of the subcutis, the other 6 cases were entirely dermal. Tumor necrosis was evident in 2 cases, melanin pigment in 2 cases, and ulceration in 1 tumor.

All cases showed uniform nests and fascicles of pale spindled or slightly epitheloid cells with finely granular eosinophilic or clear cytoplasm. There was fair pleomorphism with plump spindled nuclei and significantly prominent nucleoli. Multinucleated wreath-like tumor giant cells were observed in two-thirds of cases, but were usually present only focally. The dense cellular aggregates were encased by delicate fibrous septa. The stroma showed a sclerotic reticulated pattern. Partly, the nests of spindle cells bordered the epidermis,prima vista mimicking junctional nests of melanocytes. The specific translocation

pattern was confirmed in all cases by fluorescence in situ hybridization. Local recurrences and metastases developed in 2 and 3 patients, respectively, and 1 patient died of the disease.

Lyle PL, Amato CM, Fitzpatrick JE, Robinson WA.

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

Am J Surg Pathol. 2008;32:858-66.

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.