A rare case of muscular echinococcosis.

Echinococcosis is a zoonotic parasitic infection caused by Echinococcus species, with E. granulosus being the most prevalent in Bulgaria. The disease primarily affects the liver and lungs, while muscular involvement is exceedingly rare, accounting for less than 3% of cases, even in endemic regions. We present a case of a 25-year-old male with a painful paravertebral cystic lesion three years post-surgical treatment for pulmonary echinococcosis. Imaging revealed a non-enhancing cystic mass with solid components and adjacent vertebral lysis. Due to the lesion's location, complete en bloc excision was not feasible. A meticulous approach involving aspiration, membrane removal, and fibrous tissue excision was undertaken. The patient had an uneventful recovery and remained recurrence-free at 12 months postoperatively. This case highlights the diagnostic and therapeutic challenges of muscular echinococcosis and underscores the importance of thorough clinical evaluation, particularly in patients from endemic regions, to ensure timely diagnosis and appropriate management.