A benign or malignant neoplasm that affects the rectosigmoid region. Representative examples of benign neoplasms include lipoma and leiomyoma. Representative examples of malignant neoplasms include carcinoma, lymphoma, and sarcoma. Rectosigmoid adenomas always exhibit epithelial dysplasia and are considered premalignant neoplasms. The disease is Monarch Disease Ontology id MONDO_0002423 (rectosigmoid junction neoplasm). Also known as: neoplasm of rectosigmoid junction, neoplasm of the rectosigmoid junction, rectosigmoid junction neoplasm (disease), rectosigmoid junction tumor, rectosigmoid junction tumour, rectosigmoid neoplasm, rectosigmoid tumor, rectosigmoid tumour.