Marjolin's ulcer of the hallux.

We report the case of a 51-year-old woman with malignant degeneration of a right hallux nail bed ulcer of 20 years' duration. Histologic examination confirmed the diagnostic features of Marjolin's ulcer, a well-defined but uncommon malignant ulcer that occurs in chronic wounds and cutaneous scars. In this report, we describe the clinical and histopathologic features and the differential diagnosis of this unusual lesion.