Clear-cell variant of superficial cutaneous leiomyosarcoma associated with RB1 mutation: Clinical, dermoscopic, and histopathological characteristics

Atzori L.

Primo

Writing – Review & Editing

;Pilloni L.

Secondo

Data Curation

;Zanniello R.;Ferreli C.

Penultimo

Membro del Collaboration Group

;Rongioletti F.

Ultimo

Supervision

2020-01-01

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Abstract

Leiomyosarcoma is a relatively rare soft tissue tumor whose clear-cell variant has only been reported in leiomyosarcomas of the uterus. We report here for the first time a primary cutaneous clear-cell leiomyosarcoma in the trunk skin of a 49-year-old man, characterized by a very indolent clinical and dermoscopic presentation, mimicking a dermatofibroma. Genetic analysis of the otherwise healthy patient revealed a germline mutation in the retinoblastoma 1 gene (RB1); the same mutation was found in his son, who had previously developed retinoblastoma. Moreover, the mother of the patient had died of uterine leiomyosarcoma with clear-cell changes. Mutations in the RB1 gene occur commonly in human neoplasms. In this patient, we were able to link his clear-cell variant of cutaneous leiomyosarcoma with the loss of retinoblastoma protein expression, as revealed by immunohistochemical staining analysis.