A 26-year-old white woman presented with a 15-month history of a slowly enlarging papule involving the proximal nail fold of her left thumb. She gave no history of trauma to the region and denied any ulceration or bleeding. Although the lesion had caused disfigurement of her nail, she sought medical evaluation only because the lesion had recently become slightly painful on palpation.
Physical examination revealed a 4-mm, smooth, hyperpigmented papule overlying the medial proximal nail fold of the left thumb (Figure 1). The lesion was soft, with a gray-pink hue, and slightly tender to palpation. Longitudinal grooving of the nail plate was observed distal to the papule (Figure 2). A skin biopsy specimen was obtained (Figure 3 and Figure 4).
Leach BC, Graham BS. Papular Lesion of the Proximal Nail Fold—Quiz Case. Arch Dermatol. 2004;140(8):1003-1008. doi:10.1001/archderm.140.8.1003-a