Melanoma of the soft parts (clear cell sarcoma): a case report and review of the literature

[Soft tissue melanoma: a clinical case]

Le mélanome des tissus mous a été décrit en 1965 par Enzinger sous le nom de sarcome à cellules claires. En 1983, Chung et Enzinger le rebaptisent mélanome des parties molles en raison de similitudes immunohistochimiques avec le mélanome. Nous rapportons un cas de cette forme rare de mélanome, chez un jeune homme de 22 ans qui avait une lésion molluscoïde de la cheville sans signes cliniques de malignité, et dont l’examen histologique a permis de retenir ce diagnostic.

[Clear cell sarcoma of soft tissues: a case report]

Clear cell sarcoma or melanoma of soft tissues is a rare tumor in young adults, mainly located in the extremities. We report a new case observed in a 15-year-old teenager who had injured her left knee 1 month before hospitalization. The patient consulted for deformation of the left knee with pain and limitation in flexion. A CT scan of the knee showed a hypodense mass of the anterior compartment of the left leg. The histological and immunohistochemical study of the biopsy fragment concluded in clear cell sarcoma of the soft tissue. The histogenesis of this tumor continues to be debated and raises diagnostic challenges for the pathologist who must eliminate melanoma metastases, whose prognosis is different.

Magnetic resonance imaging features of extremity sarcomas of uncertain differentiation

The purpose of this review is to illustrate the pertinent clinical and imaging features of extremity sarcomas of uncertain differentiation, including synovial sarcoma, epithelioid sarcoma, clear-cell sarcoma, and alveolar soft part sarcoma. These tumours should be considered in the differential diagnosis when a soft-tissue mass is encountered in the extremity of an adolescent or young adult.

Monster cells in malignant melanoma

Cells with significantly enlarged nuclei have been described in basal cell carcinomas, dermatofibromas, and pleomorphic fibromas, to name a few. These cells are typically visible using low power microscopy and have been termed "pleomorphic" or "monster cells." They have not been previously described in cutaneous melanomas. We sought to determine the prevalence of monster cells in otherwise conventional biopsies of primary cutaneous melanomas and its association with other histopathologic features of this malignancy. Ninety-nine superficial spreading melanomas, nodular melanomas, and acral lentiginous melanomas/lentigo malignas were retrospectively evaluated for the presence of monster cells, multinucleated giant cells, ulceration, inflammation, and depth of invasion (Breslow level). Thirteen cases of melanoma containing monster cells were found. A statistically significant association was noted between the presence of these cells, the histologic subtype of nodular melanoma (P = 0.0125), ulceration (P = 0.0127), the depth of invasion (P = 0.0103), and the presence of multinucleated giant cells (P = 0.0016). The finding of monster cells is not an uncommon occurrence and is seen more often in nodular melanomas.

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.

[Clear cell sarcoma (malignant melanoma of soft tissues) of the calf ]

Clear cell sarcoma (malignant melanoma of soft parts) is a rare malignancy that is found in the young adult, and is generally located in the extremities of the limbs. In this study, a new case has been reported in a 24-year old male with no previous history of cutaneous melanoma. The tumor consisted of fusiform or round cells with clear or granulocytic cytoplasm and vesicular nuclei. The patient was treated by surgical resection of the tumor and postoperative radiotherapy. Eight years later, metastatic nodes were detected in the inguinal region. The histogenesis of this tumor has not yet been determined, and it poses a diagnostic problem for pathologists as it can be mistaken for a malignant metastatic cutaneous melanoma.