Extra ovarian adult granulosa cell tumor of omentum: A report of a rare entity
Authors: Khurana Anil , Kaur Paramjeet , Chauhan Ashok K. , Verma Yashpal , Bansal Nupur 
Published: February 2021

Aims: Extra ovarian granulosa cell tumor (GCT) is extremely rare tumor, assumed to arise from the ectopic gonadal tissue along the embryonal route of the genital ridge. A case of extra ovarian granulosa cell tumor of omentum in a 69 year old female presented here.

Materials and Methods: A 69 years old postmenopausal, hypertensive female presented with complaints of pain in right lumber and iliac region of one month duration. Pain was off and on and intermittent. The patient had a history of hysterectomy 12 years ago for fibroid uterus.

Results: Ultrasound examination of abdomen showed a hypoechoic lesion of size 78.1 mm x 57.3 mm in right iliac fossa with mild thickening of surrounding omentum. Another hypoechoic lesion of size 36.7 mm x 22.9 mm was seen in retroperitoneal region in supero-medial aspect of right kidney. CECT abdomen showed heterogeneously enhanced nodular lesion of size 6.6 x 6.8 cm in right lumbar region, mild thickening of surrounded omentum also seen however there was no evidence of infiltration to bowel loop seen. Uterus was not visualized. PET CT whole body revealed mildly metabolically active enlarged nodes in the bilateral level ib an ii, metabolically active large lobulated heterogeneously enhancing soft tissue density lesion in right lumbar region with non enhancing areas of necrosis. The lesion is closely abutting the anterior abdominal wall musculature antero laterally and small bowel loop medially surrounding mesenty shows increased vascularity and haziness. Colonoscopy findings were normal. Trucut biopsy of mass right lumbar region was positive for malignancy likely Round cell Sarcoma. A provisional diagnosis of retroperitoneal sarcoma of right lumbar region was made. She underwent exploratory laparotomy with excision of tumor. As per Operative findings there was approximately 8 x 7 cm, firm, omental mass present right to midline, arising from under surface of greater omentum. Ovaries were normal. Gross examination of omental mass showed nodular mass measuring 8 x 5 x 6 cm. External surface was multinodular and cut surface was grey brown to grey yellow with solid cystic areas and areas of necrosis. Microscopic examination of specimen showed Extraovarian Adult granulosa cell tumor/metastasis from occult granulose cell tumor. On IHC Vimentin, CK, SMA, Inhibin were positive, Ki67:15%, ER/PR were also positive and are negative for calretinin, thromobomodulin. Extensive necrosis was seen. After that she underwent rexploration and total omenectomy. HPE showed fat necrosis in omentum. All investigation showed no evidence of tumor in ovaries and at any other primary site then the patient finally diagnosed as having Granulosa cell tumor involving only omentum post op stage III C. Then patient was given six courses of chemotherapy with Inj Paclitaxel and Inj Carboplatin three weekly. Now patient is on regular follow up and disease free.

Conclusion: Extra ovarian adult granulosa cell tumor of omentum is rare tumor. Multimodal treatment approaches including surgery, multi-agent chemotherapy may provide a survival benefit for patients.