Journal der Deutschen Dermatologischen Gesellschaft vol:1 pages:363-368
BACKGROUND: Clear cell melanoma is a recently described variant of melanoma characterized by prominent clear cell features similar to clear cell sarcoma. PATIENTS AND METHODS: The present report describes a deeply invasive case of clear cell melanoma clinically, histologically, immunohistochemically, ultrastructurally and with the FISH technique and compares these findings with those in clear cell sarcoma. RESULTS: A 68-year-old male presented with an ulcerated, deeply invasive melanoma on the heel, corresponding to Clark level V, with a maximum tumour thickness of more than 14 mm; follow-up revealed inguinal lymph-node and lung metastases. Apart from characteristic histological features of melanoma with intraepidermal involvement, the lesion was immunohistochemically positive for 5100 protein, with HMB45 and A103 (anti-human Melan-A/MART-1), and ultrastructurally showed melanosomes. In deeply invasive parts, the lesion was indistinguishable from clear cell sarcoma, exhibiting nests, fascicles and sheets of pale-staining epithelioid to spindle-shaped cells ('clear cells') with scattered Touton-like multinucleated giant cells. Cytogenetic analysis using the FISH technique revealed a 12q13 chromosomal break in the vicinity of the ATFI gene but without ATF1 disruption. CONCLUSION: These findings may indicate the possible involvement of the ATF1 gene in clear cell melanoma tumorigenesis, similar to clear cell sarcoma with classical t(12;22) translocation.