Melanoma with an unknown primary--a case series.

Metastatic melanoma of unknown primary site accounts for approximately 5-10% of patients with metastatic melanoma. Various reasons have been suggested for the primary being unknown. These include a hidden location, complete regression of the primary or a primary origin of melanoma in lymph nodes. 24 cases with metastatic melanoma with primary of unknown site are presented. The characteristics and follow-up of the patients are discussed.