A 57-year-old post-menopausal woman (gravida 3, para 2, SA1) was referred to our hospital with intermittent lower abdominal pain. She had undergone an appendectomy in her twenties. Upon physical examination, her abdomen was soft, she had tenderness at the right lower-abdominal quadrant, and no mass was felt at the time. The patient’s routine blood analysis and renal function test were within normal limits: hemoglobin, 13.3g/dL; total leukocytes count, 7.4×103/mm3, with 75% neutrophils, 19% lymphocytes, 4% monocytes and 1.2% eosinophils in the differential count; and platelet count, 210,000/mm3. Her serum level of urea nitrogen was 9.7mg/dL, and creatinine was 0.75mg/dL. The total bilirubin (1.8mg/dL), alanine transaminase (56U/L), and aspartate aminotransferase (49U/L) were all mildly elevated, and her C-reactive protein was elevated to 10.8mg/dl. Moreover, the patient’s serum level of cancer antigen 125 (CA-125) was elevated at 329/mL, and her serum levels of cancer antigen 19-9 (CA19-9) and Carcinoembryonic antigen (CEA) were 15IU/L and 2.1ng/mL, respectively, and both were within normal values. Upon ultrasonography, the right adnexa showed a cystic mass of 8.2 cm × 6 cm with a solid lesion. The uterus was normal in size and the endometrium was thin. Magnetic resonance imaging (MRI) revealed a 8.7×7.2 cm cystic and solid mass behind the uterus. The cystic part showed a homogeneous low intensity on T1-weighted MRI and heterogeneous high intensities on T2-weighted MRI; it was also well enhanced on contrast-enhanced MRI. The uterus was normal in size and the adnexa on the opposite side were unremarkable. (Figure1) Pain in the lower-right abdomen persisted, and ovarian tumor torsion could not be ruled out. The patient then underwent an exploratory laparoscopy. A cystic lesion with a solid tumor in the right ovary (8cm in the longest diameter) was found and had infiltrated the right tubal fimbria and mesentery in the pelvis. (Figure 2) No ovarian tumor torsion was observed, and no disseminated lesion was found in the peritoneal cavity. A small amount of bloody ascites was found in the Douglas fossa, and bleeding was observed from the tumor itself. A right salpingo-oophorectomy was then performed. The part of the mesentery that had adhered to the tumor was also resected. Histopathological results revealed a high-grade serous carcinoma in the ovary and fallopian tube, as well as in the mesentery, and immunostaining revealed strongly positive staining for p53 and diffusely positive staining for WT-1 in the serous carcinoma components. (Figure 3) A region in which atypical cells had proliferated was found in the ovary, and ovarian cancer was thus diagnosed.
Upon a PET-MRI at a later date, enlarged paraaortic lymph nodes with FDG accumulation were detected (Figure 4), and no obvious mass lesions were observed in the uterus. Forty days after the first surgery, we performed a staging laparotomy: a total abdominal hysterectomy, left salpingo-oophorectomy, systematic pelvic and paraaortic lymphadenectomy, and a partial omentectomy. A complete cytoreduction was achieved. Macroscopically, a small elevated lesion was found in the uterine endometrium. (Figure 5) Pathological examination revealed that atypical columnar cells formed irregular papillary lesions and had proliferated in the elevated lesion. There was no stromal invasion or myometrial invasion by the tumor cells. Immunostaining for p53 and WT-1 were positive, estrogen receptor (ER) was negative in the endometrial cells, and the pathological diagnosis of SEIC was then made. (Figure 5) Invasion of the serous carcinoma was observed in the left ovarian ligament. Although there were no lymph node metastases found in the pelvic lymph nodes (0/33), metastases were found in the paraaortic lymph nodes (10/29). The final diagnosis was serous ovarian cancer, FIGO stage ⅢA1(ⅱ), pT2bN1M0, with SEIC. The postoperative course was unremarkable and with no major complications. The patient received six courses of carboplatin, paclitaxel and bevacizumab as a postoperative adjuvant chemotherapy and, afterward, bevacizumab as a maintenance therapy was continued. At the time of this writing, nine months have passed since the operation, and there has been no evidence of recurrence.