Giant muscle hydatid in lower extremity: a rare case with neurological symptoms as the first manifestation

BACKGROUND: Human hydatid disease typically occurs in organs such as the liver and kidney. Primary solitary intramuscular hydatid disease, however, is rare. CASE PRESENTATION: We report a case of a giant muscle hydatid in the lower extremity, with neurological symptoms as the first manifestation. The symptoms specifically manifested as intermittent pain in the right lower extremity and numbness in the sole of the right foot. However, there were no obvious abnormalities detected in electromyography and lumbar MRI. Subsequent ultrasonography and calf MRI showed that the patient had cystic lesions in the calf. The patient was initially diagnosed with a muscle hydatid cyst. Treatment involved complete surgical excision of the lesion, and the diagnosis of a hydatid cyst was confirmed through macroscopic and microscopic histopathological examination after the mass was excised. The patient was given oral albendazole, and no recurrence was observed during the 12 months of follow-up. CONCLUSIONS: This case underscores the need to consider hydatid disease when diagnosing soft tissue masses in muscles, particularly in endemic areas. Patients may initially present with atypical symptoms like peripheral nerve issues.