A case report of a rare etiology of an abdominal cystic lesion in adults: Peritoneal inclusion cysts.

Introduction And Importance: Peritoneal inclusion cysts (PICs), also known as peritoneal mesothelial cysts, are rare, benign cystic lesions primarily occurring in the abdominopelvic cavity of premenopausal women with histories of pelvic surgery or inflammation. These cysts can present with nonspecific symptoms and may mimic other abdominal pathologies, making diagnosis challenging.

Case Presentation: A 41-year-old male with no significant medical history, who experienced progressive nonspecific abdominal pain over several months. Clinical examination revealed a poorly defined mass in the right hemi-abdomen. Imaging studies, including CT and MRI, identified an elongated subhepatic cystic lesion, suggesting a peritoneal inclusion cyst or mesenteric cyst. Surgical intervention was decided following multidisciplinary team consultation. Intraoperative findings revealed a 13 cm intraperitoneal cyst with clear fluid content in the right hemi-abdomen, adherent to adjacent structures. Monobloc cystectomy was performed, and a histopathological examination confirmed the diagnosis of a peritoneal inclusion cyst.

Clinical Discussion: PICs are rare and typically affect females, with only limited cases reported in males. These cysts can be asymptomatic or present with non-specific symptoms such as abdominal pain or distension, often requiring imaging and, occasionally, surgical exploration for diagnosis. The differential diagnosis includes other cystic abdominal lesions, emphasizing the need for thorough clinical and imaging assessment. The preferred management of PICs is surgical excision, as it provides histological confirmation and minimizes recurrence risk.

Conclusion: This case highlights a rare presentation of a PIC in a male patient, underscoring the importance of considering PICs within the differential diagnosis of abdominal cystic lesions regardless of patient gender. Surgical resection remains the primary management approach, but further research is needed to establish standardized guidelines for diagnosis and treatment.