Diagnostic and therapeutic challenges in multifocal recurrent musculoskeletal hydatid cysts: a case report

Musculoskeletal hydatid cysts caused by Echinococcus granulosus are rare, representing less than 3% of all hydatid disease cases. Isolated involvement of soft tissue or bone without hepatic or pulmonary cysts is exceedingly uncommon, with most reports being single cases. This manuscript presents an extremely rare instance of a recurrent musculoskeletal hydatid cyst disease involving only the thigh and pelvis, with recurrence six years after initial resection, highlighting diagnostic and therapeutic challenges. A 38-year-old non-smoking female presented with persistent left thigh pain and progressive difficulty walking. She had undergone fine-needle aspiration and surgical excision of a thigh hydatid cyst six years earlier, followed by two years of albendazole therapy. Physical examination revealed a firm, tender mass on the anterior left thigh. Ultrasound showed a large cystic lesion (9.5 × 13.7 cm) with clear fluid. Computed tomography of the chest, abdomen, and pelvis revealed no hepatic or pulmonary cysts but identified an additional cyst in the left pelvic wall. Magnetic resonance imaging confirmed multiple cystic lesions (3–13 cm). The patient underwent surgical excision with meticulous pericystectomy, intraoperative scolicidal irrigation, and postoperative albendazole (400 mg twice daily). Histopathology confirmed hydatid cysts. At five-month follow-up, she had no early recurrence at short-term 5-month follow-up. This case underscores that multifocal musculoskeletal hydatid cysts should be considered in soft tissue masses, even without visceral involvement. Complete surgical excision without cyst rupture, combined with scolicidal agents and adjunctive albendazole, is essential to prevent recurrence. Long-term follow-up is warranted, as recurrent or multifocal disease may emerge years after initial treatment.