Metastatic melanoma of unknown primary site

Introduction. Melanomas of unknown primary site are rare, To establish thei r diagnosis the metastatic nature of the lesion must be confirmed clinicall y and histologically, the melanoid nature by histology and immunohistochemi stry. Any primary melanoma must be eliminated by careful examination of the skin and mucosa, and the absence of past surgical excision of skin lesions must be confirmed. We studied the epidemiological, clinic and prognostic c haracteristics of 19 melanomas of unknown primary site in a series of 646 m elanomas. Material and methods. This retrospective study was conducted on a series of 646 melanomas recruited over a period Of 14 years. The epidemiological (ag e, gender, phototype and family history of melanoma), clinical and prognost ic parameters (relapse and global survival rate) were analyzed in 19 patien ts. Clinical and epidemiological data were compared with the 646 melanomas of the series. The prognostic parameters were compared with the melanomas o f the series at the same stage. Results. The melanomas with unknown primary site represented 2.94 P. loo of our series and concerned lo men and 9 women with a median age of 6o years. Eight patients presented stage III melanomas, according to MID Anderson's classification and it stage IV. Relapse after surgery was observed in 63 p. 100 of patients and 9 deceased during the observation period. In stage III patients the probability of survival after 2 years was Of 51 p. 100 and fo r stage IV 34 P. 100. Discussion. In our series the frequency of melanomas of unknown primary sit e is comparable to that observed in other studies. Compared to melanomas of known primary site, there was a preponderance in men and in slightly older patients. There was a majority of single glandular localizations and no pa rticular site was preponderant. Survival of Stage I I I patients was compar able to that of melanomas of know primary site. However, for stage IV patie nts it appeared better, as has been noted in other series. Treatment of met astatic melanomas of unknown primary site should therefore be the same as t hat of classical forms. Whenever possible, surgery remains the first indica tion. Search for the primary site must be orientated by clinical examinatio n including complete examination of the skin and mucosa (ENT, ophthalmologi c and genito-urinary), eventually associated with paraclinical investigatio ns, depending on the symptoms.