Occult primary malignant melanoma: factors influencing survival.

Seventy-six patients with occult primary malignant melanoma were studied in order to detect features which would help to determine prognosis. It was found that the 5-year survival rate of these patients was: (a) no worse than in patients first presenting with one known primary lesion and metastases; (b) just as poor for women as for men; (c) more favourable if only a single lymph node was involved with secondary deposits; (d) similar whether the manner of spread of the disease was lymphatic or haematogenous; (e) similar whether there was or was not a history of a pre-existing lesion. The prognosis for occult primary malignant melanoma, although bad, is not hopeless.