Inverted follicular keratosis simulating malignant melanoma

A 93-year-old woman was noted to have a single pigmented lesion on the posterior aspect of her neck. Clinical examination revealed a 12 x 8-mm flat lesion, with an irregular border and variegated pigmentation. Dermatoscopic examination revealed a lesion with multiple colours, featureless areas and black dots, suggestive of malignant melanoma. With a presumed clinical diagnosis of malignant melanoma, an elliptical excision was performed, with a 1-cm margin. However, histological examination revealed the unexpected diagnosis of pigmented inverted follicular keratosis.