Diagnosing porokeratosis of Mibelli every time: a novel biopsy technique to maximize histopathologic confirmation.

Porokeratosis of Mibelli (PM) is a rare condition with the potential for malignant transformation that presents a clinical and pathologic diagnostic challenge. An improperly oriented biopsy may lead to the wrong histopathologic diagnosis. We report a case of PM that was previously misdiagnosed and describe a biopsy technique for suspected PM that maximizes the potential for histopathologic confirmation of the diagnosis.