Yasunari Fujinaga

The usefulness of the follicle-preserving sign in differentiating between benign, borderline, and malignant ovarian tumors on magnetic resonance imaging

Abstract Purpose The study aimed to evaluate the incidence and features of the follicle-preserving sign (FPS) and investigate its usefulness in differentiating the grades of malignancy of ovarian tumors using magnetic resonance imaging (MRI). Materials and methods This retrospective study examined 234 patients of reproductive age with a confirmed diagnosis of ovarian lesions at Shinshu University Hospital between January 2014 and December 2023. Preoperative MR images of each patient were independently evaluated by two radiologists. First, 20 patients with malignant ovarian tumors were randomly selected. To define the MR findings of normal follicles, we observed the contralateral unaffected ovary. Next, the presence of FPS in the affected ovaries was examined in all patients. Finally, the FPS frequency was statistically analyzed in relation to patient age, maximum tumor diameter, tumor malignancy, MRI magnetic field strength, MRI slice thickness (MRIST), and histological subtype. Results Among 276 ovarian lesions (benign, 146; borderline, 51; malignant, 79), the follicle-preserving sign (FPS) was significantly more frequent in benign tumors than in malignant tumors ( p  < 0.001), while no significant difference was observed between borderline tumors and the other two groups. Multivariate analysis identified patient age, tumor diameter, and MRIST as independent factors associated with FPS, with MRIST exerting the greatest influence (OR = 0.75, p  = 0.006). Compared with malignant tumors, benign tumors tended to be smaller and were imaged with thinner slices, contributing to a higher FPS incidence. Importantly, even after stratification by MRIST, benign tumors consistently showed a significantly higher FPS rate than malignant tumors across all subgroups ( p  < 0.05). FPS frequency also varied by histological subtype, being frequent in serous/seromucinous borderline tumors and immature teratomas, but uncommon in mucinous tumors irrespective of malignancy status. Conclusion The incidence of FPS was significantly higher in benign tumors than malignant tumors. However, it should be noted that FPS expression is affected by MRIST.

MR diagnosis of SCC arising within ovarian cystic teratomas: analysis of mural nodule characteristics

Abstract Purpose This study aims to evaluate and identify magnetic resonance (MR) findings of mural nodules to detect squamous cell carcinoma arising from ovarian mature cystic teratoma (SCC-MCT). Methods This retrospective study examined 135 patients (SCC-MCTs, n = 12; and benign MCTs, n = 123) with confirmed diagnoses across five different institutions between January 2010 and June 2022. Preoperative MR images for each patient were independently assessed by two experienced radiologists and analyzed following previously reported findings (PRFs): age, tumor size, presence of mural nodules, size of mural nodule, and the angle between mural nodule and cyst wall (acute or obtuse). Furthermore, this study evaluated four mural nodule features—diffusion restriction, fat intensity, Palm tree appearance, and calcification—and the presence of transmural extension. Results There were significant differences between the SCC-MCT and benign MCT groups in terms of all PRFs and all mural nodule findings (p < 0.01). Among the PRFs, “tumor size” demonstrated the highest diagnostic performance, with a sensitivity of 83.3% and a specificity of 88.6%. A combination of the aforementioned four mural nodule findings showed a sensitivity and specificity of 83.3% and 97.6%, respectively, for the diagnosis of SCC-MCT. Regarding diagnosis based on a combination of four mural nodule findings, the specificity was significantly higher than the diagnosis based on tumor size (p = 0.021). Based on these mural nodule findings, three SCC-MCT patients without transmural invasion could be diagnosed. Conclusion Mural nodule MR findings had a higher diagnostic performance than PRFs for SCC-MCT and can potentially allow early detection of SCC-MCTs. Graphical abstract

Lobular Endocervical Glandular Hyperplasia and Related Glandular Disorders: Current Status of Diagnosis with MR Imaging

Lobular endocervical glandular hyperplasia (LEGH) is a rare benign lesion of the uterine cervix that produces gastric-type mucin. First identified in 1999, LEGH is often misdiagnosed as other glandular lesions, including adenocarcinoma, human papillomavirus (HPV)-independent, gastric-type (GAS), due to similar histopathological features. LEGH is now recognized as a precursor to GAS, a malignancy with poor prognosis. This review explores LEGH's pathological and immunohistochemical characteristics and related glandular lesions, focusing on diagnostic approaches using MRI. MRI has proven essential in distinguishing LEGH from other benign cervical cystic lesions and detecting precursor conditions, such as atypical LEGH, before progression to GAS. A hallmark MRI finding for LEGH is the "cosmos pattern," featuring centrally clustered microcysts surrounded by macrocysts, achieving 95.5% specificity when combined with T1-weighted imaging. Cytology and biopsy improve diagnostic accuracy when imaging results are inconclusive, though obtaining high-quality specimens can be challenging due to lesion location. This article reviews cytological findings, the presence of gastric-type mucin, and MRI features useful for differentiating LEGH from benign non-LEGH lesions, as well as for diagnosing precancerous and malignant conditions. Recent advances in research have led to the recognition that GAS is primarily a solid rather than a cystic lesion, contributing to improved diagnostic accuracy of MRI for GAS. However, some GAS cases and atypical LEGH can still exhibit a cosmos pattern on MRI, similar to LEGH, making differentiation challenging. Therefore, we also discuss a diagnostic strategy integrating MRI findings with cytology and presence or absence of gastric-type mucin.

Useful preoperative examination findings to classify the grade of ovarian primary mucinous tumor

To evaluate various imaging features on magnetic resonance imaging (MRI) and tumor markers and their utility to assess various grades of ovarian primary mucinous tumors (OPMTs): benign, borderline, or malignant. Ninety-five pathologically diagnosed OPMTs [53 benign, 24 borderline malignant (BM), and 18 malignant] were selected in this retrospective study. MRI features of the ovarian mass, namely the maximum diameter, honeycomb loculi, solid components (SC), stained-glass pattern, and signal intensity of the cyst on T1- (T1WI) and T2-weighted imaging (T2WI) with/without fat suppression, and preoperative STMs, namely carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 19-9, and CA125, were compared between the three tumor grades using univariate analysis. We also analyzed the findings to estimate the pathological diagnosis using classification tree (CT) analysis. Maximum diameter, honeycomb loculi, SC, stained-glass pattern, signal intensity of the cyst [hyperintensity on both T1WI and T2WI (T1-hyper/T2-hyper), and hyperintense on T1WI and hypointense on T2WI (T1-hyper/T2-hypo)], and CEA and CA 19-9 concentrations were significantly different between the three tumor grades (p < 0.05). The concordance rate with the pathological diagnosis was the highest with diagnosis by the CT comprising T1-hyper/T2-hypo, CEA, and CA 19-9 and by the CT comprising T1-hyper/T2-hypo, CEA, and SC. Four types of findings were important for OPMT grading. Lesions negative for both T1-hyper/T2-hypo and CEA suggest benign; lesions positive for T1-hyper/T2-hypo and negative for CA 19-9 or SC suggest BM; and lesions negative for T1-hyper/T2-hypo and positive for CEA, or positive for both T1-hyper/T2-hypo and CA 19-9 or SC suggest malignancy.