A clinical and pathologic study of histiocytosis X in adults.

Abstract

Histiocytosis X is a neoplastic disorder of Langerhans cells that usually occurs in children. Because histiocytosis X rarely occurs in adults, the diagnosis can frequently be missed by both clinicians and pathologists. The purpose of this investigation was to characterize the clinical and pathologic findings of histiocytosis X in adults. A retrospective study of four adults with histiocytosis X was undertaken. Paraffin-embedded biopsy specimens were stained with a panel of antibodies including S-100, vimentin, Ham-56, leukocyte common antigen, proliferating cell nuclear antigen (PCNA), UCHL-1, CD43, and Ki-1. The predominant lesions were papules and pustules that usually involved the groin, axilla, and scalp. Histologically the infiltrate exhibited a periappendageal distribution. Strong positive staining for PCNA appeared to correlate with the clinical course. Histiocytosis X in adults has a predilection for skin sites rich in appendages and histologically shows a periappendageal infiltrate. PCNA staining of the histiocytes may indicate progressive disease and serve as a useful prognostic marker.