Hypertrophic osteitis of the medial end of the clavicle

A 9-year-old boy had a spontaneous onset of enlargement of the medial end o f the clavicle due to extensive sclerosis and periosteal reaction. There wa s no clinical or laboratory evidence of infection. Biopsy revealed an infla mmatory exudate, and histochemical staining for Langerhans'-cell histiocyto sis was negative. Hypertrophic sclerosis causing painful enlargement of the medial end of the clavicle in isolation should be distinguished from conde nsing osteitis and chronic recurrent multifocal osteomyelitis. An early bio psy to exclude neoplasia is recommended.