An unusual pattern of pseudoepitheliomatous hyperplasia associated with cutaneous primary melanoma: report of two cases with analysis of p53 and bcl-2 immunoreactivity.

Pseudoepitheliomatous hyperplasia (PEH) is a benign, reactive epithelial proliferation. PEH is characterized by hyperplasia of the epidermis or adnexal epithelium into irregular squamous strands that extend deep down into the subjacent dermis. PEH occurs in response to underlying infections, inflammatory or neoplastic conditions. The presence of PEH overlying cutaneous melanoma is rare. The clinical and histological features of PEH can closely mimic squamous cell carcinoma and could be misinterpreted. We report two cases of cutaneous primary melanoma associated with PEH and discuss differential diagnoses and potential role of p53 and bcl-2 in the pathogenesis of PEH.