Abstract 4342: Histological variants and sites of presentation of malignant melanoma in a resource poor setting: A histopathological review

Abstract Background: Melanoma is a malignant tumour that arises from melanocytic cells. The incidence is increasing worldwide in white population where fair skin people receive excessive sun exposure. Although relatively uncommon in Africa-Americans, recent trends shows increase incidence in Africa- Americans. Data on the incidence and biology of melanoma are few in Africa. This study review the variants and sites of melanoma in a resource poor setting in Nigeria with some immunohistochemical stains performed. Method: All cases of melanoma diagnosed in the Department of Pathology in a tertiary hospital in Nigeria over a three year period (2016-2018) were retrieved. Patient's information including site and age were also retrieved from their case notes. Immunohistochemistry using two antibodies S-100, HMB-45 was done. Results: A total 38 cases were seen during the study period with a male female ratio of 1:1.1. The age range was 5-80 years with a mean age of 48.8±18.1. The most common site for melanoma is the foot 19(50%), followed by the uvea 7(18.4%), skin and inguinal lymph node 4(10.5%), anorectal and conjunctiva had 2(5.3%). The commonest histological variant of melanoma was acral lentigenous melanoma 19(50%), Superficial spreading melanoma 4(10.5%), nodular melanoma 3(7.9%) and desmoplastic melanoma 1(2.6%). Immunohistochemistry was used on three cases to rule out differentials. Conclusion: Malignant melanoma in our setting is in contrast with African-Americans and Caucasians population base on site and histological type, hence future studies on molecular pathways of melanoma in Africa needs to be explored to show similarity or difference and the possibility of targeted immunotherapy. Citation Format: Kasimu Umar Adoke, Mohammed Faruk, Yawale Iliyasu, Saad Aliyu Ahmed. Histological variants and sites of presentation of malignant melanoma in a resource poor setting: A histopathological review [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4342.