The role of rectal magnetic resonance imaging in accurate localization and designation of colorectal cancer for optimal management: Case study.

Colorectal cancer, developing from malignant transformation of the distal gut epithelium, is the second leading cause of cancer death in the United States. We present a gentleman in his 60s who was diagnosed with colorectal cancer during a routine screening colonoscopy with no evidence of distant metastasis on subsequent staging with positron emission tomography and computed tomography (PET-CT). The outside rectal MR (magnetic resonance) imaging report localized a mass to the upper rectum. Review of the MRI at an institutional, Multidisciplinary Tumor Board designated the tumor as "rectosigmoid," straddling the rectosigmoid junction at the level of the "sigmoid take-off" (STO) or alternatively at the level of the last sigmoid artery take-off (SAT) at the origin of the superior rectal artery. The anatomic differentiation between upper rectal and lower sigmoid colon cancers carries clinical importance which is highlighted in this case report and brief literature review. Optimal anatomic localization of colorectal cancers helps direct the clinical team to tailor an individualized patient care plan.