Fig. 4

Case 3 with typical SBT. 25-year-old woman with left ovarian typical SBT. Axial T2WI (a) shows a left ovarian cystic mass with intracystic mural nodules. The largest papillary nodule (arrows) demonstrates inhomogeneous slight hyperintensity in the internal portion and hyperintensity equal to SI of cystic content in the external portion. The normal right ovary is present (arrowheads). After administration of gadolinium DTPA, the mural nodules are enhanced and the conspicuity is increased (b). On DWI, the internal portion of the largest papillary nodule shows hyperintensity equal to the SI of uterine endometrium (arrowhead) but the external portion (arrows) shows less signal intensity. c A photomicrograph of the area corresponding to the largest papillary nodule (d) shows that foci with densely branched papillae with little space among papillae are frequently found in the internal portion (arrows), corresponding to inhomogeneous slight hyperintensity on T2WI. In contrast, a loose papillary architecture of peripheral vegetation with edema (arrowheads) tends to be observed in the external portion, corresponding to hyperintensity on T2WI