Dermoscopy of trichostasis spinulosa

<p>TRICHOSTASIS SPINULOSA (TS) is a relatively common but underdiagnosed disorder of hair follicles that retain successive telogen hairs. It has been described within skin lesions (secondary TS) or as an isolated finding (primary TS). Dermoscopy may help identify the characteristic hair tuft. We report 2 cases of TS. The first case involved a 23-year-old woman who presented with a long-standing history of a light-brown papule on the lower part of her back. There was a black punctum in the upper central area of the lesion (Figure 1). Dermoscopy showed a sparse pigment network, multiple commalike blood vessels that are typical of intradermal melanocytic nevi, a few peripheral vellous hairs, and a small hair tuft emerging from the central punctum (Figure 2). Histologic examination confirmed the presence of an intradermal melanocytic nevus along with dilated folliculosebaceous bunits containing several cross-sectioned hair shafts (Figure 3). The second case involved a 30-yearold man who presented with a micropapular eruption on both flanks. Dermoscopy showed multiple vellous hairs erupting through the follicles (Figure 4).</p> <p>Hair tufts are the result of folliculosebaceous hamartomas with multiple units around a central pore (trichofolliculomas) or retained hair shafts within follicles with infundibular keratosis (TS). Trichostasis spinulosa may appear as an isolated finding or in association with expansile nondestructive lesions that narrow hair infundibulae, such as melanocytic nevi, seborrheic keratoses, syringomas, or nodular basal cell carcinomas. Dermoscopy is helpful in diagnosing TS.