Solitary Porokeratoma on the Foot: A Case Report and Literature Review.

Porokeratoma (PRKT) is a rare epidermal acanthoma that can clinically resemble other hyperkeratotic or verrucous lesions, creating potential diagnostic uncertainty without histopathologic evaluation. It typically presents as a solitary exophytic lesion that lacks the annular architecture associated with other porokeratosis variants and may therefore be misclassified on clinical examination alone. We report the case of an immunocompetent 67-year-old male with a 10-week history of a progressively enlarging hyperkeratotic nodule on the dorsal aspect of the right ankle. His examination revealed a well-demarcated lesion without annular features or surrounding satellite lesions. Histopathologic analysis following saucerization demonstrated acanthosis, papillomatosis, compact orthokeratosis, and multiple confluent cornoid lamellae with associated hypogranulosis and dyskeratotic keratinocytes, confirming the diagnosis of PRKT. This case underscores the importance of histopathologic assessment in distinguishing PRKT from other clinically similar verrucous lesions to support accurate diagnosis and guide appropriate management.