Track

Abstract

A 69-year-old woman presented to her dermatologist for pruritic, faintly red-brown, firm papules on her head and volar fingers and palms that had been present for a few months and not responded to clobetasol. Three lesions on the fingers and chin were biopsied with concern for a granulomatous or vasculitic process. The specimens revealed a dermal infiltrate of non-xanthomatized and mostly mononuclear histiocytes diffusely, as well as lymphocytes, neutrophils, and occasional plasma cells. The histiocytes expressed CD68, and only rare cells stained with S100 or CD1a. The lymphocytes expressed CD3 and overexpressed CD4 relative to CD8; CD20 stained a few lymphocytes, and CD30 was negative. These findings were interpreted to be a non-Langerhans cell histiocytosis, and, given the clinical setting, a diagnosis of generalized eruptive histiocytosis was made. Generalized eruptive histiocytosis is an exceedingly rare condition requiring clinicopathologic correlation to diagnose. It is considered to be a vacuolated, non-xanthomatized non-Langerhans cell histiocytosis, along with juvenile xanthogranuloma, benign cephalic histiocytosis, and progressive mucinous histiocytosis. Lack of foam cells and giant cells help differentiate it histologically from early xanthogranuloma and xanthoma disseminatum.