Self limiting variant of malignant cutaneous neoplasm: a rare case involving the upper lip

Keratoacanthoma (KA) is a benign epithelial proliferative lesion which frequently occurs on the sun exposed areas of the skin. Solitary KA can be difficult to differentiate from squamous cell carcinoma (SCC) both clinically and microscopically. Two histopathologic features that are helpful in distinguishing between these two lesions when they occur on sun exposed skin are the incidence of epithelial intracytoplasmic glycogen content and AgNOR counting. However, the clinical course of the lesion and its ability to self involute makes it a distinct clinical entity. Solitary KA appears on the vermilion border of the lower lip with some frequency. A case of keratoacanthoma involving the upper lip is reported presenting as an exophytic growth that resolved after excisional biopsy. Photographic documentation of the case along with relevant management protocol is discussed.