Pigmented epithelioid melanocytoma: A rare tumor

Meryem Khalidi,Hasna Kerrouch,Naoufal Hjira,Mohammed El Amraoui,Mohammed Boui

doi:10.7241/ourd.2021e.42

Abstract

Pigmented epithelioid melanocytoma is a poorly understood and rarely reported skin tumor which mimics melanoma and whose diagnosis is based on clinical, histological and immunohistochemical arguments. We report the case of a young 24-year-old patient who consulted for the sudden appearance of a plaque and then a black nodule on the left cheek, gradually increasing in size, painless and slightly infiltrated. Dermoscopy could not decide between a nodular melanoma or a blue nevus given the intensity of the pigmentation. Anatomopathological examination of the piece revealed a pigmented epithelioid melanocytoma or animal-type melanocytoma. The consequences of the complete excision were simple without recurrence after a follow-up of 9 months. It is a borderline affection, its diagnosis and treatment are necessary in order to avoid any unforeseeable malignant evolution.

Highlights

Pigmented epithelioid melanocytoma or animal-like melanoma is a rare form melanocytic tumor whose name, origin, the diagnosis, the evolutionary potential are the subject of controversy
Anti HMB45 did not show a maturation gradient and melanocytes were not stained with Ki67
Pigmented epithelioid melanocytoma (PEM) is a rare skin tumor classified as borderline melanocyte proliferation [1]

Summary

INTRODUCTION

Pigmented epithelioid melanocytoma or animal-like melanoma is a rare form melanocytic tumor whose name, origin, the diagnosis, the evolutionary potential are the subject of controversy. It is classified as borderline tumor between melanoma and the blue nevi group. Only a hundred cases has been reported, of which more than two-thirds in the last five years. It can appear de novo or on a pre-existing lesion, in particular a nevus. We report a new observation of this entity. Histology of the excisional piece showed that the nodule consisted of large, homogeneous, highly pigmented epithelioid or spindle-shaped melanocytes (Fig. 3).

DISCUSSION

CONCLUSION