A Rare Presentation of Primary Abdominal Wall Hydatid Cyst with Intraperitoneal Extension: A Diagnostic Challenge.

Abstract

Background:
Hydatid disease (cystic echinococcosis) commonly involves the liver and lungs, while primary involvement of the abdominal wall is exceedingly rare. Because muscular and parietal tissues are unfavorable for parasite implantation, abdominal wall hydatid cysts are seldom encountered and often present as a diagnostic challenge. Their nonspecific clinical appearance may mimic abscess,
hematoma, hernia, lipoma, or soft-tissue tumor, increasing the risk of misdiagnosis and hazardous invasive procedures. Intraperitoneal extension from a primary abdominal wall hydatid cyst is even more unusual and has important implications for surgical planning and prevention of spillage.
Case Report:
A 65-year-old man presented with a gradually progressive swelling over the left lower anterior abdominal wall associated with mild local discomfort. Examination revealed a solitary, non-tender,non-reducible cystic-to-firm parietal mass measuring approximately 8 × 6 cm in the left lumbar/iliac region. Contrast-enhanced computed tomography demonstrated a hydatid cyst involving the left
rectus abdominis/anterior abdominal wall musculature with multiple internal daughter cysts, along with subcutaneous and intraperitoneal extension. The intraperitoneal component was seen abutting bowel loops, psoas muscle, and urinary bladder without definite invasion. Two hepatic hydatid cysts were also identified, including one in the left lobe showing detached membranes suggestive of endocyst rupture. Percutaneous aspiration or biopsy was avoided because of the risk of rupture and dissemination. The patient underwent surgery with hydatid precautions. Intraoperatively, controlled evacuation yielded hydatid fluid and multiple daughter cysts, confirming the diagnosis and demonstrating continuity with the intraperitoneal component. Histopathology showed a laminated acellular ectocyst with parasitic elements consistent with hydatid disease. Recovery was uneventful, and postoperative albendazole therapy was advised.
Conclusion:
Primary abdominal wall hydatid cyst with intraperitoneal extension is an exceptionally rare presentation of echinococcosis. In endemic settings, hydatid disease should be considered in chronic abdominal wall masses to avoid unsafe aspiration or biopsy. Cross-sectional imaging is important for diagnosis as well as operative planning. Meticulous surgery combined with antihelminthic therapy usually offers favorable outcomes.