Clear Cell Adenocarcinoma of the Ovary Associated With In Utero Diethylstilbestrol Exposure: Case Report and Clinical Overview

Constantin A. Dasanu, MD, PhD; Thomas J. Herzog, MD


January 07, 2009

Case Report

A 45-year-old white woman was referred to our outpatient clinic with a self-discovered lump in the left lower abdominal quadrant. She was nulligravid and denied nausea, bloating, constipation, or vaginal discharge. Her medical history was unremarkable, and her health maintenance, including cancer screening, was up-to-date. She denied being sexually active. Menarche occurred at the age of 13, and she reported that her menstrual cycles were "regular." She had never been married or tried to conceive. Her family history was negative for cancer, and she denied taking any medications.

Transabdominal ultrasonography was recommended and showed a swelling thought to be ovarian in origin. Computed tomography of the abdomen and pelvis with intravenous contrast revealed a mass, 11 cm in diameter, which was apparently confined to the left ovary. Preoperative serum CA125 was normal. Staging was performed, and the tumor was confirmed to be limited to the left ovary both macroscopically and microscopically. The cytology of peritoneal washings was negative. The predominant histologic features were consistent with moderately differentiated clear cell adenocarcinoma (Figure). Elements of high-grade squamous differentiation were also present. The tumor tested negative for mucin. The rest of the specimen was free of malignancy, with the fallopian tube showing a few foci of endosalpingiosis and a paratubal cyst, and the cervix showing inflammation, squamous metaplasia, and Nabothian cysts. Although a few fibroadipose adhesions were seen in the vicinity of the right ovary, there was no evidence of cervical or uterine abnormalities. No histologic evidence of endometriosis was found in ovarian or extraovarian areas.

Figure 1.

Histologic photomicrograph, demonstrating a predominant pattern of tubular arrangement of cells with abundant clear cytoplasm.

After careful questioning, the patient's mother stated that her obstetrician prescribed DES during her pregnancy to prevent miscarriage, thus suggesting in uteroexposure to the drug. She had previously had a spontaneous abortion and a miscarriage. Medical records established that the 45-year-old patient's mother had begun taking diethylstilbestrol (Ensalstilbestrol) 25 mg daily during the 9th week of gestation, and increased the dosage to 25 mg twice daily during the 20th week of gestation. She remained on this dosage throughout the pregnancy, and delivery was uncomplicated. She stated that her daughter was healthy as a child and as a teenager.


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