Peritoneal Inclusion Cyst in an Unusual Location in a "Virgin" Abdomen: A Diagnostic Dilemma Expanding the Clinical Spectrum.

Peritoneal inclusion cysts (PICs) are benign, multilocular fluid-filled lesions that predominantly affect women of reproductive age, often arising after abdominal surgery or chronic inflammation. We report a case of a 28-year-old female presenting with chronic left upper-quadrant abdominal pain for 1 year. Radiological evaluation revealed a large cystic lesion closely abutting the left adrenal gland and adjacent organs, creating a diagnostic dilemma regarding its tissue of origin. The patient was planned for diagnostic laparoscopy, which revealed a large, thin-walled cyst containing clear serous fluid. The lesion was not arising from the suprarenal gland or the pancreatic tail. Complete excision of the cyst was performed, and histopathological examination confirmed the diagnosis of a PIC. Notably, the patient had no prior history of abdominal surgery, making this presentation particularly unusual. The postoperative course was uneventful, and at 6-month follow-up, the patient remained asymptomatic with no evidence of recurrence. This case highlights a rare suprarenal presentation of a PIC in a "virgin" abdomen, closely mimicking adrenal and pancreatic cystic pathology on imaging despite normal endocrine evaluation. It underscores the importance of imaging - particularly ultrasonography and contrast-enhanced computed tomography of the abdomen and pelvis - in evaluating cystic lesions and differentiating PICs from Paraovarian cysts, hydrosalpinx, or ovarian malignancy based on anatomical location. However, due to significant imaging overlap with adrenal and pancreatic cystic lesions, histopathological confirmation remains essential. Diagnostic laparoscopy with complete excision was crucial in establishing the diagnosis, avoiding unnecessary adrenal resection, and ensuring a favorable outcome without early recurrence.