Diagnosis: Pityriasis rotunda (PR).
MICROSCOPIC FINDINGS AND CLINICAL COURSE
Histopathologic examination of the specimen showed compact orthohyperkeratosis with rare parakeratosis. The epidermis was slightly thickened, with some melanin in the stratum corneum, a diminished granular cell layer, and an intact basal cell layer with uniform pigmentation. There was mild papillary dermal fibrosis and a mild perivascular lymphocytic infiltrate. Fungal stains (periodic acid–Schiff and Gomori methenamine silver) were negative.
The patient responded remarkably well to topical treatment with 12% lactic acid lotion. The lung opacities resolved without specific treatment.
DISCUSSION
Pityriasis rotunda is a rare asymptomatic dermatosis characterized by multiple round-to-oval, sharply demarcated, hyperpigmented or hypopigmented scaly patches, 2 to 10 cm in diameter.1 The lesions may persist for many years, often with improvement during the summer and recurrence in the winter.2 Pityriasis rotunda occurs primarily in the Mediterranean, in Africa, and in Japan.
Although PR is associated with systemic disease, the cause remains unknown. In patients of color, PR has . . . [Full Text of this Article]
