Primary chest wall soft tissue hydatid cyst: a case report and systematic review of reported cases

Abstract Background Hydatid cyst (HC) most commonly involves the liver or lungs, but it can affect almost any organ or tissue. In very rare cases, it occurs in the musculoskeletal or soft tissues, usually secondary to hepatic or pulmonary disease. However, primary skeletal muscles and soft tissues HC has also been reported, predominantly in the extremities. Primary HC involving the soft tissues and skeletal muscles of thoracic wall is exceedingly rare and remains unfamiliar to most clinicians. In this study, we report a case of primary HC of the serratus anterior muscle and systematically review all reported cases of primary chest wall soft tissue and skeletal muscle HC. Methods We present a case of primary HC in the serratus anterior muscle that was initially misdiagnosed as sarcoma. A systematic search was conducted across three electronic databases for studies published up to July 2026, following PRISMA guidelines. Articles describing patients with primary HC involving the soft tissue or muscular tissue of the extra-thoracic chest wall were included. Results A total of 1,752 publications were identified. After removing duplicates and excluding unrelated articles, 43 studies reporting 46 cases of primary chest wall soft tissue HC were included. Combined with our case, 47 patients were analyzed. The cysts were located within the chest wall soft tissues and muscular structures, including the pectoralis major and minor, serratus anterior, latissimus dorsi, trapezius, subclavius, intercostal muscles and axillary region. Most of the cases originated from hydatid disease-endemic regions. Preoperative diagnosis or suspicion of HC was made in only 20 cases. The initial differential diagnoses included breast cancer, lipoma, sarcoma, cystic lymphangioma, hematoma, tuberculosis, lymphadenitis, abscess, or intramuscular myxoma. Fine-needle aspiration or biopsy was performed in eleven cases, posing a potential risk of dissemination. Forty-three patients underwent surgical excision, and 35 received antihelminthic therapy, mostly albendazole. No recurrences were reported during follow-up. Conclusion Primary hydatid cyst of the thoracic wall skeletal muscles and soft tissues is exceedingly rare and often misdiagnosed as other soft-tissue masses. Awareness of this entity, especially in endemic regions, is crucial for accurate diagnosis and appropriate management.