Hydatid cyst of bone: diagnosis and treatment.

Osseous hydatidosis is a rare occurrence of hydatid disease. Anatomoclinical changes are, however, peculiar to this localization. From the anatomopathologic standpoint, this localization marks the torpid, insidious progression of the parasite into bone tissue, leading to an immediate diffuse, extensive, invasion process, so complete surgical eradication is rarely possible. From the clinical standpoint, whatever the localization may be, we are surprised by the latency of this affection, the patient being treated at an advanced stage, when radiologic lesions are already extensive, and the complications, especially in the spinal area, are severe. Owing to the poor biologic findings, the diagnosis of osseous hydatidosis is still primarily based on roentgenographic findings. Sometimes, however, the diagnosis is established only after surgery. Treatment of osseous hydatidosis is closer to oncologic therapy than to the usual surgical treatment of visceral hydatid cysts. Because of the poor results with medical treatment, osseous hydatidosis must be treated by a radical operation with wide excision, adapted to each localization. In the main, the prognosis of osseous hydatidosis remains poor, especially with spinal and pelvic localizations, which are the most frequent ones. The prognosis and treatment of osseous hydatidosis belong in the same category as a locally malignant lesion.