ABSTRACT
Endometriosis is the condition where endometrium gets implanted and flourishes outside the uterine cavity, most commonly in ovary and on the peritoneum which lines the abdominal cavity and viscera. Endometrial cells in areas outside the uterus are influenced by hormonal changes and respond in a way similar to the endometrium inside the uterus. Symptoms often worsen with the menstrual cycle. We present a case of 50 years old female who presented with gross abdominal distension and abdominal pain over years. CT scan showed a huge intraabdominal cyst of unknown origin which was compressing adjacent structures. Patient underwent a high risk operation and whole cyst weighing 214 kg [471 lbs] was removed along with both ovaries and uterus. Histopathologically, it was reported as endometrial cyst