Ovarian collision tumor consisting of sclerosing stromal tumor and mature cystic teratoma complicated with Meigs syndrome: A case report

Abstract

Ovarian collision tumors are uncommon and reports of their radiological appearance are even less frequent. The present study reported the world's first case of an ovarian collision tumor consisting of an ovarian sclerosing stromal tumor and a mature cystic teratoma and its imaging presentation. When a cystic solid ovarian mass combined with ascites and elevated CA125 is encountered it is frequently diagnosed as a malignant tumor, but the present case was a benign tumor. Therefore, when encountering similar cases, clinicians should not limit the diagnosis to malignant tumors to avoid rashly expanding the surgery and causing unnecessary harm to the patient. The combination of computed tomography, magnetic resonance imaging and pathology findings presented in the current study enable radiologists to learn about this disease and further assist clinicians in developing the best treatment plan.

Keywords: case report; computed tomography; magnetic resonance imaging; ovarian collision tumor; sclerosing stromal tumor.

Figure 1.

(A) CT plain scan demonstrating a massive, mixed-density mass in the pelvis of the patient, which pushed away the surrounding tissues and organs; ascites are visible around the mass. (B) CT-enhanced arterial phase image shows extensive distribution of tiny arteries in the tumor, and the parenchymal part of the tumor is mildly enhanced. (C) CT-enhanced venous phase image shows further enhancement of the parenchymal part of the tumor compared with the arterial phase. (D) CT-enhanced delayed phase image shows further intensification of the parenchymal part of the tumor. (E) The arterial phase of CT-enhanced scan shows a thick uterine artery is visible on the left posterior side of the entire mass (arrow); in addition, a small mass composed of fluid and fat is visible on the right posterior side of the entire mass; this small mass is surrounded by a substantial anterior mass and this portion does not enhance. (F) On chest CT, a substantial pleural effusion is detected on the right side of the chest cavity, whereas no fluid is detected on the left side (scale bars, 4 cm).

Figure 2.

(A) Axial T1-weighted MRI indicating a large mixed-signal lesion in the pelvis with a small lobulated solid cystic mass in the right posterior region, which is surrounded by a large anterior mass forming a ‘nested tumor’ pattern containing fatty nodules (arrow) with well-defined margins. (B) On the axial fat-suppressed T2-weighted image, the larger anterior portion of the entire occupying lesion displays with a mixed signal with a predominantly hypersignal, while the posterior portion of the fat nodule has a distinct hyposignal. (C) In the ADC image, the mass is predominantly hypersignal with a lamellar hyposignal. (D) The portion of the ADC image that is hyposignal appears as a slight hypersignal on DWI (b=1,000 sec/mm²) (scale bar, 4 cm).

Figure 3.

(A) Histology image displaying alternating pseudolobular patterns consisting of cellular and hypocellular areas (H&E; magnification, ×100; scale bar, 50 µm); (B) The first part consists of ovoid to round vacuolated oocytes and fibroblasts and the second part consists of dense collagenous tissue (H&E; magnification, ×200; scale bar, 50 µm).