Multicentric reticulohistiocytosis

A Caucasian woman in her twenties having asymptomatic papules on the hands for the past 6 months was referred by rheumatology for a skin biopsy. The patient had presented to rheumatologist for arthralgia. On physical examination, multiple, dull red, 2-5-mm papules were observed on her dorsal fingers, with most in the periungual regions. No papules or nodules were discovered on the mucosal membranes or other areas of her skin. Given the presence of characteristic "coral beads" along the periungual regions, the clinical diagnosis of multicentric reticulohistiocytosis (MRH) was rendered. A 4-mm punch biopsy revealed histiocytes with eosinophilic, homogenous, and finely granular "ground glass" cytoplasm.