Rare Chest Wall Cystic Echinococcosis in a 3-Year-Old Boy in Southwestern Nigeria: A Case Report

Abstract

Context: Cystic echinococcosis (CE) from Echinococcus granulosus larvae manifests rarely as isolated chest wall masses in children, mimicking benign cysts clinically. Diagnosis demands histopathology, as radiology and cytology often underperform amid subtle pediatric signs and atypical presentations.

Case Presentation: A 3-year-old boy from southwestern Nigeria without travel or canine exposure presented with a painless 4cm × 4 cm swelling along the right anterior chest wall (anterior axillary line) of 6 months' duration. The clinical impression was lipoma. Ultrasound showed a well-defined subcutaneous cystic lesion infiltrating pectoralis major. Fine-needle aspiration cytology indicates benign cyst contents. Complete surgical excision under general anesthesia revealed a fibrous mass with muscle involvement. Histopathology confirmed hydatid cyst featuring an acellular laminated membrane containing “scoleces” with hooklets and brood capsules.

Conclusion: Chest wall CE evades early detection due to its rarity and absence of classic risk factors, even in endemic urban settings. Routine histopathologic examination of excised cystic lesions is essential to avoid missing CE, thus enabling timely antiparasitic therapy and preventing recurrence.