CLINICAL IMAGE a Metastatic Ovarian Tumor Mimicking

E-pub ahead of print by J-STAGE CLINICAL IMAGE doi:10.2463/mrms.ci.2015-0034

A Metastatic Ovarian Tumor Mimicking Pregnancy Luteoma Found during Puerperium

Yumiko Oishi Tanaka1*, Satoshi Okada2,3, Akiko Sakata4, Tsukasa Saida1, Michiko Nagai1, Hiroyuki Yoshikawa3, Masayuki Noguchi4, and Manabu Minami1

Keywords: metastatic ovarian tumor, pregnancy, The white-colored small right ovarian mass with hem- pregnancy luteoma, sclerosing stromal tumor, MRI orrhage surrounded by the pseudo-cyst was removed (Fig. 1E). The tumor was composed of varying types (Received March 31, 2015; Accepted July 20, 2015; of malignant tumors including signet ring-like cells published online December 28, 2015) (Fig. 1F) and was positive for CDX2. The histopatho- logical diagnosis was metastatic adenocarcinoma of the ovary and its peritoneal dissemination. Advanced Introduction rectal cancer was also found via colonic fiberscope Pregnancy luteoma is a benign condition observed followed by the surgery. As the disease was resistive during pregnancy. We introduce a case with a meta- against chemotherapy, the patient was transferred to static ovarian tumor mimicking pregnancy luteoma on another hospital under best supportive care. magnetic resonance. Discussion Case Report Common malignant ovarian tumors found during A 28-year-old puerperant with fever came to our pregnancy include mature cystic teratomas, epithelial hospital. Her last delivery was uneventful. Her labo- carcinomas, yolk-sac tumors, immature teratomas, and ratory data was normal except for anemia (red blood Sertoli-cell tumors. Metastatic ovarian tumor during cell count was 3.41 × 106/μl) and elevated serum pregnancy is not so rare.1 Their diagnosis often delays C-reactive protein (7.23 mg/dl). CA19-9, CA125, and and it leads to poor maternal prognosis. carcinoembryonic antigen (CEA) were negative. She The metastatic ovarian tumors typically appear as had no family history indicating hereditary cancer well-demarcated, often bilateral tumors with hypointense syndrome. Ultrasound revealed a right adnexal mass part on T2WI. Those from the colorectal cancer often that was not recognized during the cesarean section. make multilocular cystic mass with uniform signal inten- Magnetic resonance (MR) images revealed a well-de- sity and size.2 The present case appeared as unilateral pre- marcated mass within a pseudo-cyst surrounded by dominantly solid mass that was quite different from the uterus, pelvic sidewall, and right cardinal ligament. The typical metastatic ovarian tumor from colorectal cancer. mass was composed of tiny hypointense nodules within We suspected pregnancy luteoma and SST before the background of high signal on T2-weighted (T2WI; surgery. Pregnancy luteoma is defined as hyperpla- Fig. 1A) images. Contrast enhanced T1-weighted sia of the luteinized theca cells during pregnancy. images revealed strong enhancement of the background Well-demarcated bilateral ovarian masses including stroma and the hypointense nodules remained with hypointense nodules with low signal on T2WI are a weaker enhancement (Fig. 1B, C). There was no signal hallmark of pregnancy luteomas.3 The nodules typically difference between the two parts on diffusion-weighted arrange at the periphery of the ovaries in pregnancy images (Fig. 1D). We suspected pregnancy luteoma luteoma, although they were distributed randomly in the and sclerosing stromal tumor (SST) as the similarity of present case. Such imaging findings are shared by SST pseudo-lobular pattern. showing pseudo-lobular pattern. In addition, metastatic ovarian tumor can show such characteristic which is one 1Department of Radiology, Faculty of Medicine, University of of the common histology found during pregnancy.1 Our Tsukuba, Tsukuba, Ibaraki, 1-1-1 Tennodai, Tsukuba, Ibaraki present case appeared with pseudo-lobular-like appear- 305-8575, Japan; 2Department of Obstetrics and Gynecology, ance as the tumor included densely proliferating solid University of Tsukuba; 3Department of Obstetrics and Gynecology, part and mucus-rich tumor cells with stromal edema. Tokyo Metropolitan Hospital; 4Department of Pathology, Tsukuba In conclusion, it is important to raise the possibility University Hospital of a metastatic ovarian tumor, when radiologists see a * Corresponding author, Phone: +81-29-853-3205, Fax: +81-29- well-demarcated mass with hypointense area on T2WI, 853-3205, E-mail: [email protected] even if it is unilateral and the patient is young.

1 2 Y. O. Tanaka et al.

Fig. 2. The cut surface of resected ovary shows a white and soft mass with hemorrhage and necrosis, macroscopi- cally (A). The mass is microscopically composed of adenocarcinoma with glandular formation and diffuse proliferation of signet ring-like cells (B: hematoxylin-eosin stain, high power field).

References Fig. 1. Magnetic resonance (MR) images of a 28-year-old 1. Papantoniou N, Belitsos P, Hatzipapas I, Rodolakis A, puerperant with a metastatic ovarian tumor. A well- Papaspyrou I, Antsaklis A. Excessive hirsutism in preg- demarcated mass including hypointense nodules are seen nancy because of Krukenberg tumor. J Matern Fetal within the ovary (arrowheads) surrounded by a pseudo-cyst Neonatal Med 2012; 25:869–871.

(arrows) on T2-weighted coronal image (A). The mass 2. Tanaka YO, Okada S, Satoh T, et al. Diversity in size shows homogeneous low signal on T1-weighted image (B). and signal intensity in multilocular cystic ovarian The nodules within the mass shows weak enhancement masses: new parameters for distinguishing metastatic whereas the background stroma shows intense enhancement from primary mucinous ovarian neoplasms. J Magn

(C: contrast enhanced and fat-saturated T1-weighted coronal Reson Imaging 2013; 38:794–801. image). The coronal diffusion-weighted image does not 3. Kao HW, Wu CJ, Chung KT, Wang SR, Chen CY. MR reveal restricted diffusion within the mass (D). MR images imaging of pregnancy luteoma: a case report and cor- also demonstrated the primary rectal cancer as intestinal relation with the clinical features. Korean J Radiol 2005; wall thickening (A–D, curved arrows). 6:44–46.

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