Objective: To provide a review of rare rectal tumors beyond adenocarcinoma.
Results: Rectal cancer is a common malignancy, both in the United States and abroad. In addition to adenocarcinoma, abdominal radiologists will encounter a variety of other less common rectal masses, both benign and malignant neoplasms as well as non-neoplastic mimickers. Familiarity with these conditions and their characteristic features on MRI is useful in clinical practice. In this article, a number of such conditions are discussed, with an emphasis on distinguishing features on MRI of the rectum.
Conclusion: Familiarity with the MRI features of rare rectal tumors beyond adenocarcinoma, as well as a small number of non-neoplastic mimics, is important for abdominal imagers to make diagnostic differentials and to assist in treatment planning.
Keywords: Anorectal melanoma; Basidiobolomycosis; Carcinoid; Gastrointestinal lymphoma; Neuroendocrine tumor; Rare tumors; Rectal cancer.