Rectal Cancer

Clinical History:
This is a 54-year- male with a polypoid mass in the distal rectum.

Diagnosis:
Rectal Cancer.

MR Technique:
3.0 T scanner (Siemens Skyra) using a body matrix coil coupled with an eight-channel spine coil. Image 1: sagittal T2 HASTE image (TR/TE 1600/115 ms, scan time 1 min 8 sec, slice thickness 5.0 mm); Image 2: axial T1 TSE with fat saturation after administration of 0.1 mmol/kg of gadolinum chelate (TR/TE 700/10 ms, scan time 4 min 0 sec, slice thickness 3.0 mm); Images 3: axial T2 TSE with large FOV (TR/TE 5010/113 ms, scan time 2 min 10 sec, thickness 3.0 mm).

Imaging Findings:
A 5.2 x 4.0 x 2.0 (AP x TV x CC) cm polypoid, broad-based soft tissue mass is identified protruding into the lumen from the posterior wall of the distal rectum (images 1-3). The inferior margin of the mass lies approximately 3 mm from the internal anal sphinter (image 1). No extension of the mass into the mesorectal fat is identified. A short segment of the right lateral margin of the mass may involve the muscular layers (image 2), suggesting a T1 or T2 lesion (with the definition of a T1 lesion being growth through the muscularis mucosa and extension into the submucosa, whereas for a T2 lesion the cancer has grown through the submucosa to involve the outer muscle layer).
Incidentally, a tiny (5 mm) urachal diverticulum protrudes superiorly from the anterior aspect of the urinary bladder (image 1).