2022 Volume 38 Issue 1 Pages 118-124
Cancer of unknown primary (CUP) is metastatic cancer without a clinically detectable defined primary tumor site after an adequate diagnostic evaluation. It is well recognized that CUP incidence occupies 1-5% of all malignant epithelial tumors. Herein, we report a case of primary peritoneal carcinoma diagnosed as CUP revealed by laparoscopic surgery.
A 74-year-old woman presenting with no symptoms, who had a past medical history of bilateral metachronal breast cancers and ascending colon cancer, and a family (her mother) history of breast cancer, was introduced to our facility. A new tumor located in the upper abdomen was detected on the follow-up computed tomography (CT) of the ascending colon cancer. Positron emission tomography/CT detected no other strong 2-deoxy-2 [18F] fluoro-D-deoxyglucose accumulation except in the upper abdominal tumor. A biopsy from the new tumor was performed, and the pathological diagnosis, including immunohistochemical analysis, revealed the possibility of serous carcinoma derived from the adnexa of the peritoneum. Gynecologic examinations revealed an increased serum cancer antigen 125 level; however, there were no clear abnormalities in the uterus and ovaries. After sufficient informed consent, the laparoscopic surgery was performed to resect the upper abdominal tumor, observe the abdominal cavity, and have bilateral salpingo-oophorectomy. There were no ascites and peritoneal lesions in the abdominal cavity. Although a small cyst in the left ovary was observed, there was no suspected malignancy on both adnexa. The upper abdominal tumor was completely removed, and laparoscopic surgery was performed for bilateral salpingo-oophorectomy. The pathological examinations revealed lymph node metastasis of serous carcinoma, and immunohistochemical examinations showed that ovarian cancer or peritoneal cancer was suspected as primary cancer.
However, the abdominal washing cytological diagnosis was negative, and no malignant tumors in bilateral adnexa were detected in the search for detailed pathological examinations. These findings concluded that the final diagnosis was primary peritoneal cancer, and the chemotherapy was performed according to stage III of ovarian cancer. This case suggested that laparoscopic surgery helped diagnose CUP because this method could minimize physical and mental damages.
