Although the ovarian mass by itself is supposedly benign in nature, reticulations in omental fat and small ascites raised a suspicion for malignancy. Following surgery and histological findings confirmed benign fibrothecoma with internal regression changes and bleeding. 

Fibrothecoma is a benign tumor, usually in middle-aged women. Larger tumors can be associated with ascites (or even Meigs syndrome). Often an incidental finding, but in this case sudden onset of pelvic pain may indicate an ovarian torsion.