Malignant melanocytic skin lesions from the pathologist's perspective

Abstract

Introduction. Melanoma (MM) represents a malignancy originating from melanocytes. The current WHO classification recognizes four major clinical and pathological melanoma subtypes arising in the skin: lentigo maligna melanoma, superficial spreading melanoma, acral lentiginous melanoma and nodular melanoma. Aim of study. The present paper reveals the main types of cutaneous melanoma with the highlighting of all the parameters required by the new WHO classifications, 4th edition, 2018 and AJCC 8th edition, 2017 in the histopathological bulletins. Methods and materials. The studied material was taken from the department of pathology of the Institute of Oncology and Timofei Mosneaga Clinical Republican Hospital. The macroscopic examination was performed and all the cases that presented macroscopic modifications underwent histopathological examination and immunohistochemical analysis. The positive and differential diagnosis was based on the usual immunohistochemical reactions for melanoma: S-100, HMB45, Melan A, MART1, SOX-10, P16 and Ki-67. Results. In most of the cases the diagnosis of melanoma was established by using the routine hematoxylin and eosin staining and only in about 10% of cases we used immunohistochemical and molecular genetic tests. Conclusion. The characteristic morphological features, supported by immunohistochemistry are important in making the correct diagnoses.