Peritoneal inclusion cysts are uncommon abdominopelvic cysts seen in perimenopausal women. It is often misdiagnosed clinically as an ovarian tumor due to similar presentation and mimicking findings on radiology. We describe a perimenopausal woman presenting with pelvic mass. Her clinical finding on radiology suggested an ovarian tumor; however, biopsy revealed it as peritoneal inclusion cysts. We discuss the possible ways to avoid such mistakes.