Multicentric Reticulohistiocytosis with Dermatomyositis-like Eruptions

Abstract

A 68-year-old man presented with polyarthritis, proximal muscle weakness, and erythema of the face, arms, neck, and anterior chest that resembled the V-neck sign. Initially, dermatomyositis (DM) was considered because of the erythema, polyarthritis, and muscle weakness. He also had mediastinal and hilar lymphadenopathy on contrast-enhanced computed tomography. Unexpectedly, a biopsy of the forehead skin revealed numerous multinucleated giant cells. A biopsy of a solitary nodule on the dorsum of his right middle finger revealed similar multinucleated giant cells with ground-glass cytoplasm, leading to the diagnosis of multicentric reticulohistiocytosis (MRH). Although MRH is rare, it should be remembered that MRH can mimic DM.

Keywords: dermatomyositis; multicentric reticulohistiocytosis; rheumatoid arthritis; sarcoidosis.

Figure 1.

Erythematous rash of the patient. The distribution of the erythema resembles the V-neck sign.

Figure 2.

A small red to flesh-colored nodule on the dorsum of the right middle finger (arrowhead).

Figure 3.

Numerous multinuleated giant cells and slight lymphocyte infiltration. The nuclei are arranged haphazardly or clustered at the center. The cells have prominent nucleoli and pale cytoplasm (periodic acid-Schiff staining, ×400).