Basal Cell Carcinoma With Matrical Differentiation Case Report and Review of Management

Basal cell carcinoma with matrical differentiation (BCCMD) is a rare subtype of basal cell carcinoma (BCC), with only about 43 cases described in the literature. It is characterized by typical BCC morphology, including basaloid cell aggregates with peripheral palisading, along with areas of matrical differentiation containing shadow cells, trichohyalin granules, and corneocytes. Immunohistochemically, the basaloid component expresses BerEP4, while the matrical component often shows diminished BerEP4 and positive β-catenin and epithelial membrane antigen staining. BerEP4 represents an immunohistochemical marker that highlights basaloid cells and is commonly used to aid in identifying basal cell carcinoma and distinguishing it from other skin tumors. A 79-year-old man presented with a new 9-mm pearly papule on the right forehead, which was diagnosed as BCCMD following histopathologic and immunohistochemical evaluation. The lesion was successfully treated with one stage of Mohs micrographic surgery, and the patient remained disease-free after nine months of follow-up. Due to overlapping histologic features with other follicular neoplasms, diagnosis is critical, and management strategies are not well established. While most cases have been treated with standard excision, Mohs surgery may offer superior margin control, especially for tumors in cosmetically sensitive regions. Rare reports of metastasis suggest a potentially more aggressive clinical course than typical BCC. Comprehensive excision and long-term surveillance are recommended to optimize outcomes and further characterize this rare variant.