Cystic Echinococcosis of the Ilium Treated with Curettage and Microwave Thermoablation Followed by Bone Cement Installation: A Novel Treatment Technique for a Rare Disease

Bone cystic echinococcosis (CE) is a rare condition requiring a high level of suspicion during primary diagnosis. Wide excision of the lesion is the gold standard of treatment, posing however extreme challenges in certain parts of the skeleton, since it may well be accompanied by increased morbidity. We report the case of a 35-year-old Caucasian female with iliac bone CE, referred to our department (a regional referral center for the treatment of patients with musculoskeletal tumors). The patient reported gradually increasing dull pain at the right iliac fossa and antalgic gait, with an onset of approximately 5 years before her referral. Bone CE diagnosis was established based on physical examination, imaging studies, and two subsequent CT-guided core needle biopsies, performed within a period of 3 months, of which the second was diagnostic. Following a musculoskeletal tumor multidisciplinary meeting, it was decided that the optional treatment was the surgical removal of the cyst. Aiming to minimize the morbidity accompanying a wide resection of the lesion, we performed extended curettage of the lesion through a typical iliac spine approach, followed by microwave ablation of the walls of the remaining bone cavity. The remaining iliac defect was treated with the installation of polymethyl methacrylate bone cement. The patient reported immediate remission of symptoms postoperatively and was able to return to everyday activities two weeks postoperatively. She began oral treatment with albendazole on the 7th postoperative day. She remained symptom-free for a period of 25 months, until she developed a seroma at the gluteal area, which was treated with simple drainage. On her latest follow-up six months later, she remained symptom-free and was able to perform all her previous activities. Microwave ablation may serve as a useful adjuvant modality when treating patients with bone CE, in order to prevent relapse of the disease.