A 28-year-old man presented to our clinic for the evaluation of widespread black spots and cysts, in which recurrent infections could not be controlled by topical and systemic antimicrobials. He was first noted at birth to have a rudimentary toe on the right foot. By the age of 8 years, he had developed pitting on the neck and sole, many of which contained black dots. Over subsequent years, pigmented papules representing pigmented basal cell carcinomas (BCCs) also began to appear on the neck and chest. The patient gave a history of recurrent abscesses and cysts developing on the lesions after the age of 14 years. His personal history was negative for epileptiform attacks and congenital cataract. There was no parental consanguinity and no family history of any similar skin condition.
Dermatologic examination revealed aggregated, linear, discrete, dilated, follicular orifices plugged with keratinous material on both sides of the neck, extending down to the upper chest. In some areas, these comedo-like pits were associated with erythematous papules, nodules, cysts, and scars. Some follicules had a rudimentary hair, and others no hair at all. In addition, there were multiple, small, black, glistening papules, characteristic of pigmented BCCs (Fig. 1). Interfollicular hypopigmentation was also observed. On the medial edge and sole of the right foot, there was a linear patch of pitting. There was also a skin-colored, soft, 2 cm pedunculated nodule arising from the medial aspect of the great toe, which was diagnosed as a rudimentary toe (Fig. 2). The rest of the physical examination was normal. The patient's general health was good.
Histopathologic examination of the skin lesions revealed dilated and invaginated keratin-filled follicular structures and well-defined, keratin-filled cysts. A peri-infundibular inflammatory infiltrate was also observed. Multiple BCCs were detected adjacent to nevus comedonicus (Fig. 3).
The patient was treated with amoxicillin/clavulanic acid, plus daily applications of tretinoin gel 0.025% and benzoyl peroxide 5% with some improvement. Cryosurgery with liquid nitrogen was performed on the smaller BCCs. In addition, the larger BCCs and some persistent painful cysts were surgically removed. The patient remains under observation and is well.