BACKGROUND: Clear cell sarcoma of soft tissues (CCSST), even synonymically termed malignant melanoma of soft tissues, is a peculiar malignant tumor with both a prolonged clinical course and a final poor prognosis. Whilst its neuroectodermal histogenesis is most likely, its nosological position is still a matter of debate. Light microscopy (LM), immunocytochemistry (ICC), and electron microscopy (EM) investigations have shown both a melanocytic and schwannian differentiation. Recent findings from cytogenetic analysis documenting a reciprocal translocation between the long arms of chromosomes 12 and 22 [t(12:22)(q13;q12.2)] not seen in cutaneous melanomas nor in other neurogenic sarcomas support CCSST as a distinct entity. MATERIALS AND METHODS: A case of CCSST arising in the preparotid region of a young man with a clinical history of two previous surgical interventions was admitted in 1994 and is herein reported. This patient was previously cured twice in different institutions: the first time he was diagnosed with a "melanoma, NOS" of the face and surgically treated 10 years earlier. The second time--meaning one year earlier the admission--this patient was again surgically treated for a local recurrence which was interpreted as a myoepithelioma (clear cell type) of salivary gland origin. A morphological, immunocytochemical, and ultrastructural analysis performed on the last recurrence is herein presented. RESULTS: On LM the tumor exhibited the classic morphological appearance comprised both of clear and eosinophilic cells with prominent nucleoli, focally containing cytoplasmic granules of melanin pigment. At ICC expression of vimentin and S-100 protein was diffusely demonstrated as well as the melanoma associated antigen HMB-45 was even albeit focally documented.
BACKGROUND: Clear cell sarcoma of soft tissues (CCSST), even synonymically termed malignant melanoma of soft tissues, is a peculiar malignant tumor with both a prolonged clinical course and a final poor prognosis. Whilst its neuroectodermal histogenesis is most likely, its nosological position is still a matter of debate. Light microscopy (LM), immunocytochemistry (ICC), and electron microscopy (EM) investigations have shown both a melanocytic and schwannian differentiation. Recent findings from cytogenetic analysis documenting a reciprocal translocation between the long arms of chromosomes 12 and 22 [t(12:22)(q13;q12.2)] not seen in cutaneous melanomas nor in other neurogenic sarcomas support CCSST as a distinct entity. MATERIALS AND METHODS: A case of CCSST arising in the preparotid region of a young man with a clinical history of two previous surgical interventions was admitted in 1994 and is herein reported. This patient was previously cured twice in different institutions: the first time he was diagnosed with a "melanoma, NOS" of the face and surgically treated 10 years earlier. The second time--meaning one year earlier the admission--this patient was again surgically treated for a local recurrence which was interpreted as a myoepithelioma (clear cell type) of salivary gland origin. A morphological, immunocytochemical, and ultrastructural analysis performed on the last recurrence is herein presented. RESULTS: On LM the tumor exhibited the classic morphological appearance comprised both of clear and eosinophilic cells with prominent nucleoli, focally containing cytoplasmic granules of melanin pigment. At ICC expression of vimentin and S-100 protein was diffusely demonstrated as well as the melanoma associated antigen HMB-45 was even albeit focally documented.