Erythroplasia of Queyrat with Zoon's balanitis: a diagnostic dilemma.

Chronic erythematous lesions of the penis may result from a variety of underlying causes that form a part of differential diagnosis. They are difficult to diagnose only upon clinical examination and may necessitate performing a biopsy to confirm the diagnosis and also identify the coexisting disease. We report a case of erythroplasia of Queyrat (EQ) with Zoon's balanitis and discuss the classification of the lesion through the analysis of overlapping histological features. A middle-aged uncircumcised man presented with two long-standing erythematous prepucial penile lesions unresponsive to antibiotics. Biopsy performed to establish the diagnosis revealed non-invasive severe dysplastic changes in the epithelium that is typical of EQ. Subepithelial histological features were characteristic of Zoon's balanitis. The extent and nature of inflammatory infiltrate in the dermis described in the literature is quite varied in EQ and in the spectrum of non-cicatricial balanoposthitis. The overlap of histological findings could result in the diagnostic dilemma of a coexistent lesion, as described in this case report.