An infant with self‐healing cutaneous Langerhans cell histiocytosis followed by isolated thymic relapse

Thymic involvement with Langerhans cell histiocytosis (LCH) typically occurs in children as part of multi‐system (M‐S) LCH. Patients who develop skin‐only LCH during infancy may either follow a self‐healing course with spontaneous regression or may progress to M‐S involvement. We describe a male infant who developed isolated thymic LCH after spontaneous complete regression of isolated cutaneous lesions. His erythrocyte sedimentation rate and C‐reactive protein increased temporarily during the skin‐only stage of LCH, and increased again considerably during the thymic relapse. Even for patients with skin‐only LCH, these laboratory data might indicate possible relapse or late progression of the disease. Pediatr Blood Cancer 2009;53:229–231. © 2009 Wiley‐Liss, Inc.