Comparison of MR imaging features of uterine neuroendocrine carcinoma and uterine malignant lymphoma.

We retrospectively investigated the characteristic magnetic resonance (MR) imaging findings of uterine neuroendocrine carcinoma (UNEC) compared to those of uterine malignant lymphoma (UML). Nine consecutive female patients with UNEC and 5 female patients with UML participated in this study. MR imaging features were evaluated retrospectively. On MR imaging, seven of 9 UNEC lesions and no UML lesions showed an exophytic growth pattern. All 9 UNEC lesions and no UML lesions showed a growth pattern along the surface of the endocervix or endometrium. Only 1 UNEC lesion and all 5 UML lesions showed diffuse enlargement of the uterus. No UNEC lesions and all 5 UML lesions showed a multinodular shape. These findings showed significant differences between lesions. Findings for margin, endophytic growth pattern, signal intensity, and homogeneity on T2-weighted and T1-weighted imaging did not differ significantly between lesion types. Apparent diffusion coefficient was significantly lower for UML lesions than for UNEC lesions, but was quite low for both types. Local invasion to surrounding tissues was more frequent in UML lesions than in UNEC lesions. There was no significant difference in the frequency of lymphadenopathy between two entities. UNEC lesions tended to show an exophytic growth pattern and growth along the surface of the endocervix or endometrium, even when diffuse enlargement of the uterus was present, while all UML lesions showed a multinodular shape and diffuse enlargement of the uterus without thickening of the cervical epithelium and endometrium.