[Eosinophilic granuloma (histiocytosis-X) with lung and bone manifestations].

A 26 year-old male presented with a spontaneous pathological fracture of the right femur caused by an osteolytic lesion. A chest X-ray demonstrated the coexistence of interstitial pulmonary fibrosis. Fibrocaseous tuberculosis and widespread malignancy were ruled out by appropriate investigations. The differential diagnosis, as based on the histological examination of the bone tumour, rested between hyperparathyroidism complicated by pulmonary disease and eosinophilic granuloma with lung manifestations. Hyperparathyroidism was ruled out by the absence of clinical and biochemical evidence of a disturbance of calcium metabolism. The diagnosis of histiocytosis-X was established by the histological appearance of the lung biopsy.