Background Ovarian cancer is the fifth-leading cause of cancer related deaths for women worldwide, and women have a lifetime risk of 1.3%. Factors known to increase your risk are familial genetic syndromes such as BRCA1/BRCA 2 tumor suppressor gene mutations, increasing age, obesity, and post-menopausal hormone therapy. Women present with abdominal pain/pressure, fatigue, and early satiety (1). Ovarian cysts have an unknown prevalence since most women are asymptomatic and they tend to be found incidentally while performing imaging for another cause. However, if causing symptoms, the patient may complain of pelvic pain/pressure, vaginal bleeding, and early satiety with or without nausea. Cancer antigen 125 (CA125) is a glycoprotein antigen present on various tissues including those lining the ovaries, fallopian tubes, and non-gynecological organs such as stomach and colon. It can be present in healthy tissue and malignant tissue. The normal range is between 5–35 IU/mL and values > 35 IU/mL are present in 6% of ovarian cysts (3).

Case Presentation Our patient was a 43-year-old female who presented with a chief complaint of abdominal fullness and dyspnea. She had been having ongoing increasing abdominal girth and pressure for the past nine months with new onset dyspnea at rest. On physical exam she was cachectic, abdomen was firm/distended, and she had 3+ bilateral lower extremity edema up to the knees bilaterally. The CT abdomen was significant for a left sided adnexal mass 20x20x30cm with severe abdominal distention and ascites. She underwent paracentesis on three consecutive days (day 1: 2.3L, day 2: 15L, and day 3: 2L) for a total removal of 19.3L. The ascitic fluid studies showed bloody fluid with >400,000 red blood cells without malignant cells present. Blood tests were unremarkable and subsequent cancer antigens were obtained. The results were: cancer antigen 125 (CA125) 114, carcinoembryonic antigen (CEA) 4.2, and cancer antigen 19-9 (CA19-9) 93. Patient underwent total abdominal hysterectomy (TAH) and bilateral salpingo-oophorectomy (BSO). After excision of the mass, the final histopathology showed a benign epithelial cyst measuring 27cm.

Discussion Rapid onset worsening abdominal pressure accompanied with diffuse ascites and elevated CA125 leads one to the differential diagnosis of gynecological malignancy, mainly ovarian in origin. However, giant ovarian cysts defined as >10cm have a similar presentation. CA125 is associated with malignant ovarian cancer, but the specificity of this marker is low and can be falsely elevated in benign conditions and premenopausal women (4).