Osseous hydatidosis - A diagnostic mimic and a therapeutic challenge: Clinicopathological and radiological features of 21 cases from India

BACKGROUND: Bone constitutes a rare site of involvement in hydatid disease, associated with a diagnostic challenge. OBJECTIVE: The present study is an analysis of the clinicopathological features of osseous hydatidosis, emphasizing on its diverse appearance on radiologic imaging. MATERIALS AND METHODS: Twenty-one patients with histopathologically confirmed osseous hydatidosis were included. RESULTS: The most involved site was spine (n = 7), followed by pelvis (5), femur (4), and a single case, each in the rib, tibia, ulna, humerus, and talocalcaneal joint, respectively. The radiological differential diagnoses ranged from infections to tumors and tumor-like lesions. The spinal lesions were osteolytic and were diagnosed as tuberculosis, aneurysmal bone cyst, hemangioma, and metastasis, on imaging. The femoral lesions were diagnosed either as fibrous dysplasia or as primary cystic bone lesions. The pelvic lesions mimicked cystic angiomatosis, giant cell tumor, low-grade chondrosarcoma, and tuberculosis. Histopathologic examination revealed characteristic acellular lamellated membranes in all the cases. Following diagnosis, all the patients underwent anti-helmenthic treatment after the histopathological diagnosis. One patient with ankle joint involvement underwent talocalcaneal fusion followed by below-knee amputation and in another patient the affected femoral segment was excised with fibular graft reconstruction. Recurrence was noted in two patients with lesions in the spine and talocalcaneal joint, respectively. CONCLUSION: This study emphasizes upon the need to consider hydatid disease in the list of differential diagnosis of osteolytic lesions of the bone.