Large Endometriotic cyst-masquerading as ovarian malignancy

Endometriosis usually affects premenopausal females. Its pathogenesis is not completely understood. The presence of functioning endometrial glands and stroma outside the uterine cavity is known as endometriosis. Endometriosis can be found in both ovaries, the pouch of Douglas, pelvic peritoneum, and uterosacral ligaments. Cystic forms of endometriosis can occasionally present as a huge abdominal mass, mimicking ovarian malignancy. Hereby, we present one such case of a large endometriotic cyst in a pre-menopausal female. She underwent surgery, and the histopathology, along with immunohistochemical examination, proved it to be a case of endometriotic cyst. Although this diagnosis is relatively rare, this should be considered as a differential diagnosis in the case of cystic lesions in premenopausal females.