Eur Radiol (2008) 18: 1757–1759 DOI 10.1007/s00330-008-0917-x INTERPRETATION CORNER M. K. Demir N. Heybeli T. Atay H. Özdemir Received: 6 November 2007 Revised: 4 December 2007 Accepted: 6 January 2008 # European Society of Radiology 2008 Hydatid disease: a rare cause of pelvic pain (2008: 5b) Abstract We describe a case of hydatid disease as a rare cause of pelvic pain. Although the involvement of pelvic bones makes diagnosis chal- lenging, characteristic imaging find- ings of the cysts in the other tissues highly suggest the diagnosis of hydatid disease. Keywords Hydatid disease . MRI . CT . Pelvis . Bone M. K. Demir . H. Özdemir Department of Radiology, Trakya University School of Medicine, Edirne, Turkey N. Heybeli Department of Orthopaedics and Traumatology, Trakya University School of Medicine, Edirne, Turkey Case report A 61-year-old male patient presented with left hemipelvic dull pain that increased by compression. The patient was in good health and had an unremarkable medical history. Pelvic radiography demonstrated a large destruction and sclerosis in the left iliac bone and sacrum. CT examination revealed a lytic, expansile lesion and marginal sclerosis associated with cortical destruction (Fig. 1). On MRI, multiple soft tissue cystic masses were also detected in left paraspinal and gluteal muscles besides left iliac and sacral bone lesion (Fig. 2). Chest X-ray showed a smooth, round solitary pulmonary nodule in the right lower zone (Fig. 3). Routine laboratory tests were normal. The diagnosis of hydatidosis was suggested by imaging findings. Biopsies before and during surgery confirmed the diagnosis (Fig. 4). Combined surgical and medical therapy was needed. A team approach was performed with thoracic, general and orthopedic surgeons. Many forms of treatment were done, such as curettage and excision of lesions, grafting and cementing of bone defects, local measures as inactivation of cysts by silver nitrate and hypertonic solutions, and long-term antiparasitic medical therapy. At the 2-year follow-up examination, the patient was disease-free. Discussion Echinococcus granulosus, responsible for hydatid disease, most often lodges in the liver and lungs. Even in endemic areas, osseous involvement is rare, comprising 0.5% to 2.5% of all human hydatidosis [1, 2]. It is most commonly seen in the spine and pelvis, followed by the femur, tibia, humerus, skull, and ribs. The clinical manifestations of T. Atay Department of Orthopaedics and Traumatology, Suleyman Demirel University Medical School, Isparta, Turkey M. K. Demir (*) 11, kisim, Yasemin Apt, D blok, Daire 35, Ataköy, 34158 Istanbul, Turkey e-mail: demirkemal@superonline.com Tel.: +90-533-5531246 Fax: +90-284-2352730