Case Study Details Rare Instance of Ovarian SCC Resulting From Endometriosis

A new case study highlights a 71-year-old patient who received a diagnosis of mixed squamous and clear cell ovarian adenocarcinoma stemming from endometriosis.

Findings were published in the journal Gynecologic Oncology Reports.¹

The median survival time for patients with squamous cell carcinoma (SCC) of the ovary is around 26 months. In comparison, high-grade serous ovarian adenocarcinoma has a median survival time of 50 months and is more common than SCC. Since 2019, just 36 cases of ovarian SCC had ever been reported in English language studies.

In the current case study, the patient presented with “nonradiating, sharp, right lower quadrant pain” that lasted for 10 days and lower abdominal bloating that lasted for a month. She had a history of hypertension and hyperlipidemia, but no postmenopausal bleeding or changes in bowel movements or urination.

The patient had used oral contraceptive pills for 26 years, had 1 vaginal delivery at age 26, and did not have a history of hormone replacement therapy. She also had no family history of gynecologic cancer.

Providers carried out a CT scan that showed a cystic pelvic mass originating from her right ovary. The patient was referred to a gynecologic oncologist and “lab work revealed an elevated CA [cancer antigen] 19-9 of 2392.5 and elevated CA-125 of 211,” the authors wrote.

CA 19-9 and CA-125 are tumor markers, high levels of which may indicate cancer growth.^2,3

A cyst was then found intraoperatively and drained, while a frozen section showed invasive SCC. In addition to the cyst’s removal, the patient’s bilateral ovaries and tubes, cervix, and uterus were also removed.

“Histology showed mixed carcinoma with a clear cell carcinoma component (25%) and a squamous cell carcinoma component (75%),” the researchers said. Because an adjacent endometrioma was found, they hypothesized the tumor components may be a result of endometriosis.

Her cancer was considered high risk for recurrence and she was thus recommended to undergo treatment with carboplatin and paclitaxel every 3 weeks for a total of 6 cycles. She also began taking entecavir before starting chemotherapy.

At the time of publication, 4 months had passed since she completed chemotherapy, and both physical examinations and imaging showed no evidence of the disease.

In addition, “CA 19-9 normalized to 10, and CA 125 normalized to 14,” the authors wrote. The patient continued taking entecavir for 6 months after chemotherapy completion to prevent a flare-up of hepatitis B.

Although most ovarian SCCs result from a secondary transformation of mature cystic teratomas, transformation can also occur in an endometrioma, the researchers explained.

“Ovarian SCC that originates from endometriosis likely comes about through neoplastic squamous transformation of the endometrial-type epithelium,” they added.

Previous research also suggests this form of ovarian SCC may have a worse overall survival rate compared with the SCC that transforms from a dermoid cyst.

Because such a small number of primary ovarian SCC cases are reported in the literature, a robust body of evidence does not exist for postoperative regimens and the National Comprehensive Cancer Center does not offer guidelines for this type of cancer in the ovary.

“Ovarian SCC represents a rare and aggressive histology that does not currently have an established standard of care treatment,” the authors wrote.

“Based on our review of the literature, we would recommend treating these patients with initially cytoreductive surgery if the chance of optimal cytoreduction is high. Thereafter, even in stage IA disease, we would recommend treatment with adjuvant platinum-based chemotherapy and close surveillance,” they concluded.

References

1. Mills A, Saleh M, Kombak FE, Flint M, and Kolev V. Mixed squamous and clear cell ovarian adenocarcinoma arising from endometriosis in a 71 year old patient. Gynecol Oncol Rep. Published online June 27, 2023. doi:10.1016/j.gore.2023.101225

2. CA 19-9 blood test. MedlinePlus. Updated November 8, 2022. Accessed July 29, 2023. https://medlineplus.gov/lab-tests/ca-19-9-blood-test-pancreatic-cancer/#:~:text=What%20is%20a%20CA%2019,to%20cancer%20in%20your%20body

3. CA 125 test. Mayo Clinic. Published March 31, 2022. Accessed July 29, 2023. https://www.mayoclinic.org/tests-procedures/ca-125-test/about/pac-20393295