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

Melanoma of the soft parts (clear cell sarcoma) is an uncommon soft tissue sarcoma that occurs in tendons and aponeuroses, usually of the lower extremity and is believed to be of neural crest origin. Although the exact histogenesis of this tumor is unknown and some controversy still exists, the generally accepted view is that it arises from neural crest cells that have the capability to produce melanin. Because melanin or melanosomes can be demonstrated in a majority of these cases, the term melanoma of the soft parts (MSP) has been advanced. These tumors commonly metastasize and have a very poor prognosis.