To the Editor.—
A ring of depigmentation appeared around a cutaneous tumor that proved on microscopic examination to be a histiocytoma. To my knowledge, halo formation has not been previously associated with histiocytoma.
Report of a Case.—
A 35-year-old man had an asymptomatic tumor on the medial aspect of the left thigh for approximately ten years. He sought medical advice because of the recent appearance of "a white ring" around the tumor.The lesion was approximately 1.5 × 1 cm in diameter, elevated, reddish, firm to palpation, and surrounded by a sharply defined ring of hypopigmentation (Fig 1). Clinically, the lesion resembled a histiocytoma.
The specimen showed a connective tissue tumor that occupied most of the dermis (Fig 2). The epidermis was somewhat hypertrophic, and
Berman A. Halo Around a Histiocytoma. Arch Dermatol. 1978;114(11):1717-1718. doi:10.1001/archderm.1978.01640230087034