Large cell neuroendocrine carcinoma originating from the uterine endometrium: a report on magnetic resonance features of 2 cases with very rare and aggressive tumor

Neuroendocrine carcinomas (NEC) of the female genital tract are aggressive and uncommon tumors, which usually involve the uterine cervix and ovary, and are seen very rarely in the endometrium. Only less than 10 cases of large cell NEC (LCNEC) of the endometrium have been reported in the literature and their radiological findings are not well described. We report here two cases of pathologically proven LCNEC of the uterine endometrium. In both cases, the uterine body was enlarged and the tumor occupied part of the uterine cavity. Endometrial mass exhibited heterogeneous high intensity on T2-weighted magnetic resonance (MR) images, and diffusion-weighted MR images revealed high intensity throughout the tumor, consistent with malignancy. LCNEC is a highly malignant neoplasm without particular findings in terms of diagnostic imaging and pathology, so its preoperative definitive diagnosis is very difficult. However, when laboratory test, pathologic diagnosis and MR imaging suggest a poorly differentiated uterine malignancy, positron emission tomography-computed tomography scan should be performed as a general assessment to help with diagnosis.