Malignant Melanoma in Lagos, Nigeria: Elucidating Histopathologic Prognostic Factors

Malignant melanoma (MM) is the most lethal of all cutaneous malignancies, accounting for about 79% of skin cancer related deaths. In blacks, it is associated with greater morbidity and mortality compared to Caucasians. Breslow thickness and ulceration status are two of the most important histopathologic prognostic factors in MM. No study on MM in Nigeria has however examined these factors.

Formalin-fixed paraffin-embedded (FFPE) tissue blocks and corresponding Haematoxylin and Eosin (H&E) stained slides of all confirmed cases of MM from January 2005 to December 2014 in the AMP Department of Lagos University Teaching Hospital (LUTH) were retrieved.

Fifty-two MM cases were histologically diagnosed in LUTH during the study period which represented 1.0% of total solid malignancies. Forty-three of these occurred in the skin accounting for 19.7% of all skin malignancies and making MM the 3rd commonest skin malignancy after squamous cell carcinoma (SCC) and kaposi sarcoma (KS). Eighty eight percent (88%) of the tumour were in Clark's stage IV and V while 84% had Breslow thickness >4mm. Ulceration was present in 67%. The Clark's level and Breslow thickness were correlated with the ulceration status of the tumour. There is significant correlation between the Breslow thickness and ulceration with p-value < 0.05 while there is no significant association between the Clark's level and ulceration.

MM constituted a significant proportion of skin malignancy in LUTH and majority of the cases present at an advanced stage. Breslow thickness and ulceration statuses of the tumour are important histopathologic parameters that should be reported in all MM biopsies.