Hiroki Kato

MRI characteristics of ovarian metastasis: differentiation from stomach and colorectal cancer

Abstract Purpose To evaluate the efficacy of MRI findings for differentiating between ovarian metastasis from stomach cancer (OMSC) and colorectal cancer (OMCC). Methods Twenty-six patients with histopathologically proven ovarian metastasis (n = 8 with 12 OMSCs and n = 18 with 25 OMCCs) were enrolled in the study. All patients had undergone pelvic MRI before surgery. We retrospectively reviewed MRI findings and compared them between the two pathologies. The black scrunchie sign was defined as a thick (> 5 mm) and lobulated hypointense rim (> 180°) with central hyperintense areas on T2-weighted images. Results Predominantly solid lesions (100% vs. 20%, p < 0.01), black scrunchie sign (33% vs. 0%, p < 0.01), and flow void (67% vs. 20%, p < 0.01) were frequently observed in OMSCs than in OMCCs. The signal intensity ratio of solid components on T2-weighted images (3.30 ± 0.70 vs. 2.52 ± 0.77, p < 0.01) and gadolinium-enhanced T1-weighted images (2.21 ± 0.57 vs. 1.43 ± 0.32, p < 0.01) were significantly higher in OMSCs than in OMCCs. Furthermore, hyperintense areas within cystic components on T1-weighted images (71% vs. 18%, p < 0.01) and stained-glass appearance (44% vs. 0%, p < 0.01) were frequently observed in OMCCs than in OMSCs. Conclusion The black scrunchie sign was only observed in OMSCs. OMSCs always exhibited predominantly solid lesions and had higher signal intensity of solid components on T2- and gadolinium-enhanced T1-weighted images. OMCCs usually presented as cystic lesions, usually accompanied by hyperintense areas within the cystic components on T1-weighted images.

A comparative analysis of MRI findings in endometrial cancer: differentiation between endometrioid adenocarcinoma, serous carcinoma, and clear cell carcinoma

To assess the magnetic resonance imaging (MRI) findings of endometrial cancers and to reveal the differences between endometrioid carcinoma (EC), serous carcinoma (SC), and clear cell carcinoma (CCC). In this study, 274 consecutive patients with histopathologically confirmed endometrial cancer (231 ECs, 25 SCs, and 18 CCCs) who underwent MRI before hysterectomy were enrolled. MRI images were retrospectively reviewed and compared between the three pathologies. The maximum diameters (55.6 ± 34.7 vs. 39.3 ± 21.6 vs. 39.4 ± 26.8 mm) (p < 0.05) and apparent diffusion coefficient (ADC) values (1.11 ± 0.21 vs. 0.84 ± 0.17 vs. 0.86 ± 0.16 × 10 SCs frequently exhibited a heterogeneous signal with peritoneal dissemination and abnormal ascites. Alternatively, CCCs tended to have a larger tumor size and higher ADC values with an infiltrative growth pattern, heterogeneous signal, and abnormal ascites. • SCs tend to have a heterogeneous signal intensity with peritoneal dissemination and abnormal ascites compared to ECs. • CCCs tend to have a heterogeneous signal intensity with an infiltrative growth pattern and abnormal ascites compared to ECs. • CCCs have a larger tumor size and higher ADC values compared to ECs and SCs.

Magnetic resonance imaging findings of extrauterine high-grade serous carcinoma based on new pathologic criteria for primary site assignment

Background There has been no study that has reported magnetic resonance imaging (MRI) findings of extrauterine high-grade serous carcinomas (HGSCs) that have been histologically determined by the new criteria. Purpose To assess MRI findings of extrauterine HGSCs based on new pathologic criteria. Material and Methods Fifty patients with histopathologically proven extrauterine HGSCs, who underwent pretreatment gadolinium-enhanced MRI, were included in this study. After surgery, the primary sites were histopathologically determined based on new criteria for primary site assignment in extrauterine HGSCs as follows: fallopian tube (n = 34); ovary (n = 9); primary peritoneal HGSC (n = 1); and tubo-ovarian (n = 6). We retrospectively reviewed MR images and compared the MR findings between tubal and ovarian primaries. Results MRI patterns with tubal primaries were classified as ovarian cancer (62%), peritoneal cancer (35%), and fallopian tube cancer (3%). MRI patterns with ovarian primaries were classified as ovarian cancer (78%) and peritoneal cancer (22%). The frequency of the involvement of the fallopian tube, ovary, peritoneum, uterus, and lymph node was not significantly different between the two pathologies. There was no significant difference in the abnormal amount of ascites, hemorrhagic ascites, or characteristics of the ovarian lesions between the two pathologies. Conclusion On MR images, tubal primaries almost always exhibited ovarian or peritoneal cancer pattern, but rarely exhibited fallopian tube cancer pattern. MR findings could not accurately differentiate between tubal and ovarian primaries; therefore, histopathologic investigation is essential for determination of the primary site of extrauterine HGSCs.

CT and MRI characteristics of ovarian mucinous tumors associated with mature teratomas

This study aimed to evaluate the CT and MRI features of ovarian mucinous tumors associated with mature teratomas. The present study enrolled a total of 34 patients with histopathologically proven ovarian mucinous tumors associated with mature teratomas, including collision tumors composed of mucinous tumors and mature teratomas and mucinous tumors arising from mature teratomas. All patients underwent preoperative pelvic CT and/or MRI. Imaging findings were retrospectively reviewed. Histopathological diagnosis of mucinous tumors included mucinous cystadenoma in 22 patients, mucinous borderline tumor (MBT) in 10 patients, and mucinous carcinoma in two patients. The mean maximum tumor diameter was 168 mm (range, 39-314 mm). All tumors were unilateral, well-defined, predominantly cystic, and multilocular. A total of 14 tumors (41 %) had fewer than 10 loculi, while 12 tumors (35 %) had 30 or more. Fatty components were observed in 30 tumors (88 %), and 20 of 30 tumors (67 %) had multiple fatty components. On MRI, stained glass appearance was observed in 20 of 29 tumors (69 %). On CT, nodular calcifications within fatty components were observed in 12 of 21 tumors (57 %), whereas flattened calcifications within the septa of non-fatty components were observed in 7 of 21 tumors (33 %). Pseudomyxoma peritonei (PMP) was observed in three patients (9 %) with MBT. Ovarian mucinous tumors associated with mature teratomas typically presented as large, multilocular cystic lesions with fatty components and teratoma/mucinous tumor-associated calcifications. Although PMP was uncommon, it was rarely observed in patients with MBT.

Can MRI features differentiate ovarian mucinous carcinoma from mucinous borderline tumor?

Our purpose was to determine if MRI could be used to distinguish ovarian mucinous carcinoma (MC) from mucinous borderline tumor (MBT). This study included 63 consecutive patients with histopathologically proven ovarian mucinous neoplasms (11 MCs and 52 MBTs) who underwent preoperative contrast-enhanced MRI. MRI images were retrospectively reviewed and compared between the 2 pathologies. The maximum tumor diameters (219.7 ± 80.8 mm vs. 177.4 ± 56.5 mm, p <  0.05) and maximum mural nodule (MN) diameters (41.7 ± 33.8 mm vs. 6.6 ± 8.9 mm, p <  0.01) were significantly larger in MCs than in MBTs. MNs larger than 5 mm (82 % vs. 29 %, p <  0.01) and abnormal ascites (45 % vs. 12 %, p <  0.05) were significantly more frequent in MCs than in MBTs. Apparent diffusion coefficient (ADC) values of MN were significantly lower in MCs than in MBTs (1.20 ± 0.25 × 10 MRI findings of these 2 pathologies overlapped considerably. Compared with MBTs, MCs exhibited larger tumor size, larger MN size, and lower ADC values of MN, and MCs more frequently had MNs larger than 5 mm and abnormal ascites. T2 hypointense microcysts might be a specific MRI finding in MBTs.

MR findings for differentiating decidualized endometriomas from seromucinous borderline tumors of the ovary

Decidualized endometriomas (DEs) and seromucinous borderline tumors (SMBTs) exhibit similar MR findings including markedly hyperintense mural nodules within endometriotic cysts on T2-weighted images. The present study aimed to assess the efficacy of MR imaging for differentiating between DEs and SMBTs of the ovary. MR images of 8 DEs and 14 SMBTs were retrospectively assessed and compared according to pathologies. With regard to quantitative assessments of mural nodules, the number and signal intensity ratios (SIRs) on T1-weighted images were significantly greater in DEs than in SMBTs (11.0 ± 8.4 vs. 4.3 ± 4.1, p < 0.05 and 2.36 ± 0.56 vs. 1.49 ± 0.27, p < 0.01, respectively), whereas the height was significantly lower in DEs than in SMBTs (4.5 ± 1.4 mm vs. 21.9 ± 11.4 mm, p < 0.01). However, there were no significant differences between DEs and SMBTs in the SIRs on T2-weighted images, SIRs on diffusion-weighted images, and apparent diffusion coefficient values. With regard to qualitative assessments of mural nodules, the lobulated margin, pedunculated configuration, and T2 hypointense core were significantly more frequent in SMBTs than in DEs (71% vs. 0%, p < 0.01; 86% vs. 0%, p < 0.01; and 43% vs. 0%, p < 0.05, respectively). The number, height, SIRs on T1-weighted images, lobulated margin, pedunculated configuration, and T2 hypointense core of mural nodules within endometriotic cysts were useful MR findings for differentiating DEs from SMBTs.

Pretreatment tumor-related leukocytosis misleads positron emission tomography-computed tomography during lymph node staging in gynecological malignancies

AbstractThe accuracy of fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) can be influenced by the increased glycolytic activity of inflammatory lesions. Here, using clinical data obtained from gynecological cancer patients, tumor samples and animal models, we investigate the impact of pretreatment tumor-related leukocytosis (TRL) on the diagnostic performance of 18F-FDG-PET/CT in detecting pelvic and paraaortic lymph node metastasis. We demonstrate that pretreatment TRL misleads 18F-FDG-PET/CT during lymph node staging in gynecological malignancies. In the mechanistic investigations, we show that the false-positive 18F-FDG-PET/CT result for detecting nodal metastasis can be reproduced in animal models of TRL-positive cancer bearing G-CSF expressing cervical cancer cells. We also show that increased 18F-FDG uptake in non-metastatic nodes can be explained by the MDSC-mediated premetastatic niche formation in which proinflammatory factors, such as S100A8 or S100A9, are abundantly expressed. Together, our results suggest that the MDSC-mediated premetastatic niche created in the lymph node of TRL-positive patients misleads 18F-FDG-PET/CT for detecting nodal metastasis.