MR Imaging of Uterine Epithelioid Trophoblastic Tumor: A Case Report

Abstract

Epithelioid trophoblastic tumor (ETT) is a rare gestational trophoblastic neoplasm of chorionic-type intermediate trophoblasts, and it is most frequently located in the lower uterine segment and endocervix. Due to the epithelial-growth pattern with geographic necrosis exhibited by the neoplastic cells, ETT is commonly confused, both clinically and pathologically, with squamous cell carcinoma. Although there have been no previous reports of ETT focusing on computed tomography (CT) or magnetic resonance imaging (MRI) findings, we report a case of uterine ETT with special attention to the MRI findings referring to the pathological findings and MR images of previous reports. A 42-year-old Japanese woman (gravid 1, para 1) presented with uterus enlargement during screening, and complained of recent-onset lower abdominal pain. The MRI showed a solid tumor throughout the entire myometrium of the lower uterine segment, with the hemorrhagic cystic portion extending to the posterior subserosal space. Following hysterectomy, the final pathological diagnosis was ETT. An ETT is essentially a solid tumor composed of intermediate trophoblasts that exhibit an epithelial-like growth pattern and contain geographic necrosis with calcification. In our case, MRI revealed a non-specific-intensity solid tumor in the lower uterine segment with massive necrosis and hemorrhage extending to the subserosa. While it is difficult to distinguish between ETT and uterine carcinomas, recognition of certain tumor shapes and necrosis could enable more accurate diagnosis before treatment.

Epithelioid trophoblastic tumor of the uterus: A case report with radiologic–pathologic correlation

“…The ETT in our case did not show cystic components within the lesion on CT and MR images. Kageyama et al reported that the cystic component contained massive amounts of necrotic tissue and hemorrhagic materials, and no cystic wall was present . On the other hand, our case revealed focal hemorrhage and an area of extended coagulation necrosis.…”

“…Four cases among five previous reports exhibited cystic components within lesions on radiological images . The ETT in our case did not show cystic components within the lesion on CT and MR images.…”

“…calcification) on non‐contrast CT images. In previous reports, calcification was revealed only in microscopic examination, although it was unclear on radiologic examination . Hence, our case is the first in which calcification was revealed on CT images.…”

“…Another interesting MR finding in our case was that on T2WIs the tumor appeared as a hypointense mass compared to the normal uterine myometrium. In contrast, the solid components of the tumors appeared as hyperintensities on T2WIs in two of three previous reports that described T2WI findings . In the remaining article, tumor detection on T2WIs was difficult .…”

“…To the best of our knowledge, only one report describing the radiologic–pathologic correlation of ETTs has been published, although we found approximately 100 case reports of ETT. Herein, we report a very rare case of uterine ETT with characteristic magnetic resonance (MR) and computed tomography (CT) findings distinct from those of other GTDs and uterine carcinoma, and discuss the radiologic–pathologic correlation.…”