This patient went on to have an en-bloc resection.
MACROSCOPIC DESCRIPTION: A segment of bowel, 158mm in length. Tethered to the anterior serosa of the specimen, is a full thickness segment of bladder wall, including mucosa. 54mm from the proximal resection margin, there is a sessile tan tumour with an indurated centre and raised irregular edges, measuring 43mm in axial length and 47mm transversely, occupying the full luminal circumference with stenosis. The tumour invades through the full thickness of the bowel wall into the pericolic fat. Anteriorly, the tumour invades into the detrusor muscle of the bladder wall. Posteriorly, involvement of vessels by tumour is seen, creating a deposit 8mm in maximum dimension, that extends to abut the serosa. Uncomplicated diverticular disease is seen.
MICROSCOPIC DESCRIPTION: Sections of the colon show features of moderately differentiated adenocarcinoma. The tumour forms complex glandular structures, surrounded by desmoplasia. The tumour cells have enlarged vesicular nuclei, prominent nucleoli and moderate amounts of eosinophilic cytoplasm. Tumour-infiltrating lymphocytes are inconspicuous. The tumour is seen to extend through the full thickness of the bowel wall into the adjacent attached bladder. The tumour invades into the detrusor muscle but not involving the urothelium. It is surrounded by abundant active chronic inflammation with microabscess formation. In some areas, the tumour is seen to involve the serosa and there is also tumour in the pericolic fat. Scattered foci of vascular invasion are seen including involvement of lymphatics and veins. Perineural invasion is also identified. The tumour is completely excised with clear proximal, distal and radial resection margins. The bladder resection margins are also clear. 8 out of 38 lymph nodes show metastatic carcinoma including extranodal spread.
Final diagnosis
Moderately differentiated adenocarcinoma, with local invasion:
- tumour extends through the full thickness of bowel wall into detrusor muscle of the bladder, forming colovesical fistula
- tumour seen on serosa of the colon and in pericolic fat
Staging
- Dukes stage D
- AJCC stage IVB
- TNM: T4 N2 M1