Neuroendocrine carcinomas of the endometrium are rare tumors that can be pure, combined with endometrioid adenocarcinoma, or a component of malignant mixed müllerian tumor. Recently, a case of combined small cell carcinoma and papillary serous carcinoma of the endometrium was described for the first time. We report the first case, to our knowledge, of combined large cell neuroendocrine carcinoma and papillary serous carcinoma of the endometrium, with an unusual pagetoid spread of the neuroendocrine component into normal endometrial and endocervical glands. The endometrial carcinoma had a small serous component, but most of the tumor was characterized by solid sheets of medium to large cells with abundant mitotic figures, numerous apoptotic bodies, and foci of necrosis. This component was diffusely positive for neuroendocrine markers. Following surgery, the patient was treated with radiation therapy and chemotherapy. She was without evidence of progression at 5 months of follow-up.