Langerhans cell histiocytosis in a 4-year-old boy with extensive bony lesions

Langerhans cell histiocytosis (LCH) is a rare benign disorder of unknown etiology with an estimated incidence of 4 to 5 cases per 100,000 persons per year. LCH can involve almost all parts of the body; however, sever extensive bone involvement is rare. The purpose of this report was to describe the case of a 4-year-old boy who presented with a history of a 2-month old fall injury. Physical examination revealed an angular deformity of the left proximal femur, torticollis, and limited motion of the cervical spine. A comprehensive skeletal survey, computed tomography (CT) scans of the chest, abdomen and pelvis as well as a bone scintigraphy were performed. Multiple lytic lesions of the skull, ribs, sternum, scapulae, spine, pelvis, humeri, femora, tibias and fibulas could be seen in the plain radiographs and CT scans. Bone scintigraphy revealed increased uptake of the technetium radioisotope in multiple bones. Malignant metastasis was excluded. Immunohistochemical staining and electron microscopy confirmed LCH. The patient was treated with systemic chemotherapy (vinblastine and prednisone). Twelve months later his symptoms subsided. The presented case revealed some very rare involvement sites for LCH such as the femoral epiphyses, vertebral plates, sternum, fibulas, and cervical spine. It is also very unusual to find so many involvement sites in one patient.