Basaloid Cell Hyperplasia Overlying Dermatofibroma

Abstract

Dermatofibromas (DFs) are benign neoplasms of the dermis typically found on the extremities of young adults. In approximately 3-5% of cases, basaloid cell hyperplasia (BCH) is observed overlying DFs. BCH is characterized by the proliferation of basaloid cells within the epidermis. BCH and superficial basal cell carcinoma (BCC) share many histological features, making their differentiation challenging. It is therefore unclear if the proliferation of basaloid cells in DFs represents an inductive process or, conversely, a malignant transformation indicative of BCC. The primary objective of our study was to determine whether BCH can be distinguished from superficial BCC using histology and immunhistological techniques. The histological and immunohistochemical characteristics of 43 DF samples with overlying BCH revealed significant similarities in staining patterns with those of superficial BCC described in the literature. These findings point to the need for innovative methods, such as molecular techniques, to refine diagnostic accuracy.

Keywords: Ber-EP4; CK-20; Ki-67; basal cell carcinoma; basaloid cell hyperplasia; dermatofibroma.

Figure 1

(a): Basaloid cell proliferation over dermatofibroma, case nr. 6, HE; (b): BerEp4, (c): Ki-67, (d): CK20, (e): basaloid cell proliferation over dermatofibroma, case nr. 7, HE; (f): BerEp4, (g): Ki-67, (h): CK20. All images: 100×.