A 58-year-old asymptomatic woman was referred to our gynecologic oncology unit for the management of a left adnexal mass found during a routine gynecologic examination. Her personal history included an emergency splenectomy at the age of 4 years old, following traumatic splenic laceration after a car accident. The patient's work-up (including transvaginal ultrasound and MRI) confirmed a pelvic solid mass, which was reported as suspicious for malignancy and classified as Ovarian-Adnexal Reporting & Data System-MRI 5. An exploratory laparoscopy was performed, showing a reddish blue lesion located at the left broad ligament. Histologic analysis showed the presence of splenic tissue and normal adnexa. The postoperative follow-up was uneventful.Pelvic splenosis is a challenging diagnosis rarely made preoperatively due to concern for malignancy. In the presence of a pelvic mass, the collection of a detailed patient's history, including information about previous splenic rupture, might raise suspicion for pelvic splenosis.