Imaging features of mesonephric-like adenocarcinoma of the endometrium

Objectives Mesonephric-like adenocarcinoma (MLA) is a newly classified endometrial carcinoma known for its poor prognosis, although the imaging characteristics of this tumor have yet to be reported. This study aims to clarify the imaging characteristics of MLA of the endometrium. Methods Imaging findings of eight pathologically confirmed cases with MLA were retrospectively analyzed. The mean patients were 65 years old (57-72) and were postmenopausal. Contrast-enhanced MR was available in all cases, including dynamic contrast enhancement (DCE) in seven. Pre- and post-contrast CT and FDG-PET/CT were performed in six and two, respectively. We analyzed the size, location, growth pattern, signal intensity on T1-, T2-weighted images, the pattern of enhancement on DCE and static phase, ADC, local extension on MR, density on pre-contrast CT, SUVmax on FDG-PET/CT and metastatic diseases. Results Seven of the eight patients had an endophytic, eccentric growth pattern. The tumor location within the uterus, the signal intensity, and the density varied. However, the ADC was low, and SUVmax was high in all available cases. The enhancing pattern of the solid part was transient early in five and gradually in two of seven patients with DCE, and a micro-honeycombing pattern was observed on the static phase in six of the eight cases. Conclusion Although in a limited number of cases in a single-institute analysis, large eccentric masses within the myometrium with restricted diffusion and a micro-honeycombing pattern may be imaging characteristics of MLA. Advances in Knowledge This is the first manuscript describing the imaging features of MLA.