Recognizing Histopathological Simulators of Melanoma to Avoid Misdiagnosis

Abstract

Melanocytic lesions have a wide morphological spectrum, ranging from benign nevi to malignant melanoma. In contrast to a diagnosis of a benign nevus, a diagnosis of melanoma could mean intensive treatment, lifetime monitoring, and a worse prognosis. Therefore, melanocytic tumors are notoriously challenging and associated with a high risk of litigation in surgical pathology. After describing the basic features of nevi and melanoma, this article describes the detailed clinical and histological features of those lesions that share many similar features with melanoma. The entities included are Spitz nevi and atypical Spitz tumors (AST), Reed nevus, dysplastic nevus, cellular blue nevus (CBN), deep penetrating nevus, combined nevus, recurrent nevus, irritated nevus, congenital pattern nevus, acral nevus, and nevi of special sites. Knowledge of these imitators can help pathologists distinguish between benign and malignant cases and avoid misdiagnosis.

Case Report: Nevus-Melanoma Misdiagnosis in Seborrheic Keratosis of the Eyelid

“…5,8 Genetic, idiopathic, and sun exposure factors have an effect on the emergence of seborrheic keratosis. 9,10 According to a study by Brash et al, ultraviolet radiation caused specific mutations in the pyrimidine dimer tumor suppressor gene p53 of keratinocytes. Keratinocytes with this DNA damage will undergo apoptosis and clinically will appear as keratosis.…”

“…Malignant melanoma also presents as an amelanotic lesion which makes it difficult to identify, especially in pale-skinned individuals. 1,9 The similar clinical features of seborrheic keratosis, melanocytic nevus and melanoma is a challenge for clinicians to differentiate between malignant and benign lesions through history and physical examination. Predilection for benign tumors is mostly found on the upper eyelid, while malignant tumors are more commonly found on the lower eyelid.…”

“…Seborrheic keratosis is a benign intraepidermal neoplasm that develops from epidermal keratinocytes. 5,9 The presentation features of Volume 10; Issue: 2; February 2023 seborrheic keratosis preparations are welldefined coin-like pigmented lesions in which keratin and epidermal basal cells are present. There is a picture of massive keratin (hyperkeratosis) and cysts filled with keratin (horn cysts) and keratin invagination into the main locus (invagination cysts), if there is squamous inflammation it will differentiate to form whirling foci resembling a vortex (eddy squamous) which is a typical appearance of seborrheic keratosis.…”

Deep Learning Approach to Classify Cutaneous Melanoma in a Whole Slide Image

“…Second, melanoma and benign nevus share many characteristics, leading to some confusion during histopathological diagnosis [ 21 ]. For example, blue nevus, combined nevus, deep penetrating nevus, and atypical Spitz nevus exhibit unusual maturation patterns [ 21 ]. Atypical Spitz nevus can also exhibit cellular atypia and poor circumscription [ 21 ].…”

“…For example, blue nevus, combined nevus, deep penetrating nevus, and atypical Spitz nevus exhibit unusual maturation patterns [ 21 ]. Atypical Spitz nevus can also exhibit cellular atypia and poor circumscription [ 21 ]. These are all benign lesions and, therefore, do not require aggressive treatment.…”