Two Distinct Lesions of Inverted Follicular Keratosis of the Scalp: A Case Report

Inverted follicular keratosis (IFK) is a rare benign tumor characterized by endophytic growth on the follicular infundibulum. IFK clinically and pathologically resembles other malignant lesions such as squamous and basal cell carcinomas due to similar basosquamous proliferation. Hence, the differentiation of these lesions is important as treatments vary substantially. We present the case of a 60-year-old female with two distinct skin lesions on her scalp. The lesions were excised, and the specimens were sent for histopathologic, immunohistochemistry, and human papillomavirus (HPV) testing. Due to the lesion's location, morphological ambiguity, and predilection for the elderly, differentiation from malignancy or viral-infected skin lesions is difficult. Adequate assessment must be done histopathologically to confirm the benign nature of the lesion as IFK presents usually as a singular lesion. Our case report investigates further whether HPV contributes to the development of IFK in this particular case. In this instance, HPV had no contribution to the development of the lesion.