(Poster #307) Fibroepithelioma of Pinkus in Continuity with a Pigmented, Nodular Growth Pattern Basal Cell Carcinoma: An Undeniable Association with Malignancy?

Abstract

Fibroepithelioma of Pinkus (FeP), a rare variant of basal cell carcinoma (BCC), was first described in 1953 by Dr. Pinkus. As subsequent reports suggested FeP as a benign trichoblastoma, controversy developed regarding its classification as a malignant tumor. Due to the rarity of reported cases of FeP, its tumor classification remains somewhat unclear. Here we present a case of a 77-year old male with FeP in continuity with BCC on his lower back. The shave biopsy histologically demonstrated definitive features of FeP located peripherally of a centrally located BCC. The characteristic appearance of FeP can be recognized as thin cords of basaloid epithelial strands arising from the epidermis, anastomosing downward into the fibrous stroma to form a honeycomb pattern. The adjacent pigmented BCC presented as a large nodule of basaloid cells with peripheral palisading of nuclei along with several melanin deposits. The rare occurrence of FeP in continuity with BCC not only offers insights into the connection between FeP and BCC, but also questions the impact that the presence of FeP may have on the prognosis of that BCC. Furthermore, given the limited reported cases of FeP in continuity with BCC, it calls to question if this low prevalence is due to the actual rarity or if these cases are underreported and misdiagnosed as just BCC. Therefore, it emphasizes the importance of increasing awareness of FeP and continuing the investigation of the underlying pathogenesis to help resolve its potential prognostic implication.

Financial Disclosure:
No current or relevant financial relationships exist.

Published in: ASDP 58th Virtual Annual Meeting

Publisher: The American Society of Dermatopathology
Date of Conference: October 20-24, 2021