Basal Cell Carcinoma Arising within Seborrheic Keratosis

Abstract

Malignant tumour development within a seborrheic keratosis (SK) is extremely rare. Though the most commonly developed malignant tumour is the basal cell carcinoma (BCC), other tumour types have also been reported in literature. Herein, we will report a superficial type BCC case developed within SK localized in hairy skin of a 78-year-old female patient. In immunohistochemical evaluation, diffuse positive staining with CK19 and over-expression in p53 compared with non-neoplastic areas were determined in neoplastic basaloid islands. It is always not easy to differentiate especially superficial type BCC cases from non-neoplastic epithelium of SK with histopathological evaluation. As far as this reason we believe that in difficult differentiation of these 2 lesions, in order to show the differentiation in basal epithelium, immunohistochemical evaluation may be helpful.

Basaloid tumors arising from seborrheic keratosis: Malignant basal cell carcinoma or benign basaloid follicular hamartomatous proliferation?

“…In Taiwan, the incidence of BCC was 8.4 per 100 000 person‐years in 2015 compared to 285 per 100 000 person‐years in the United Kingdom and 226 per 100 000 person‐years in the United States . Moreover, among previous reported cases, many were diagnosed solely based on hematoxylin and eosin staining, CK19 positivity, or BerEP4 positivity . These stains can help distinguish basaloid cells from squamous cells but cannot differentiate benign basaloid follicular proliferation from BCC …”

“…There are reports of an association of SK with malignant skin tumors. It can be either malignant transformation or collision tumor, especially, with BCC …”

Ceratose seborreica em idosos de uma região de savana tropical

“…Embora a CS seja reconhecida como um dos tumores benignos mais comuns da pele, especialmente na senescência [2][3][4] , sua etiologia e patogênese ainda não são totalmente compreendidas 1 , porém apresenta forte associação hereditária 5 .…”

“…Podem surgir em qualquer região tegumentar, porém as principais regiões anatômicas acometidas pela CS são a cabeça e o pescoço, seguidos do tronco, membros superiores e membros inferiores 6 , especialmente nas áreas expostas ao sol 7 , exceto nas regiões palmares e plantares 1,3,4 , e raramente na região genital 5 .…”

“…Um dos motivos principais para uma investigação mais rigorosa consiste no fato de que a CS pode apresentar evolução para um melanoma maligno 4,8 .…”