A CLINICAL AND PATHOLOGICAL-STUDY OF HISTIOCYTOSIS-X IN ADULTS

Background: Histiocytosis X is a neoplastic disorder of Langerhans cel ls that usually occurs in children. Because histiocytosis X rarely occ urs in adults, the diagnosis can frequently be missed by both clinicia ns and pathologists. Objective: The purpose of this investigation was to characterize the clinical and pathologic findings of histiocytosis X in adults. Methods: A retrospective study of four adults with histio cytosis X was undertaken. Paraffin-embedded biopsy specimens were stai ned with a panel of antibodies including S-100, vimentin, Ham-56, leuk ocyte common antigen, proliferating cell nuclear antigen (PCNA), UCHL- 1, CD43, and Ki-1. Results: The predominant lesions were papules and p ustules that usually involved the groin, axilla, and scalp. Histologic ally the infiltrate exhibited a periappendageal distribution. Strong p ositive staining for PCNA appeared to correlate with the clinical cour se. Conclusion: Histiocytosis X in adults has a predilection for skin sites rich in appendages and histologically shows a periappendageal in filtrate. PCNA staining of the histiocytes may indicate progressive di sease and serve as a useful prognostic marker.