Colon adenocarcinoma - splenic flexure

CT Abdomen / Pelvis

Technique:

Volume acquisition through the abdomen and pelvis has been obtained with oral contrast only due to poor renal function.

Findings:

At the level of the splenic flexure, there is a 4 cm segment of circumferentially thickened colon, with a single focus of mural calcification. Immediately upstream of this thickening, the large bowel is mildly distended up to 6 cm. Distal to this, calibre of the remaining colon is normal. Surrounding this thickening, there is associated stranding of the subcutaneouspericolic fat. No intraabdominal lymphadenopathy. The small bowel has an unremarkable appearance with no evidence of small bowel distension.

There are only scattered sigmoid diverticula, with no evidence of diverticulitis.

There are innumerable bilateral renal cysts, almost all of them demonstrating simple water attenuation. Within the right kidney, there are 8 mm and 14 mm rounded hyperdensities that do not however demonstrate fluid attenuation.

Within segment 3 of the liver, immediately adjacent to the falciform ligament, there is a 14 mm rounded hypodensity that demonstrates water attenuation. There is also a smaller subcentimetre cyst within segment 2. There is a 16mm region of irregular hypodensity within the posterior aspect of segment 3. Tiny calcified granuloma noted within segment 6 of the liver.

Possible subcentimetre stone within the neck of the gallbladder. The common bile duct is not dilated.

The pancreas, spleen and adrenal glands have an unremarkable appearance on non-contrast imaging.

Minor bilateral dependent change. No suspicious bony lesion.

Conclusion:

Circumferential mural thickening of the splenic flexure with surrounding fat stranding, is concerning for a colonic tumour. Mild upstream distension of the colon, suggests this is at least partially obstructing. Endoscopic evaluation should be considered.

Bilateral polycystic kidneys. Two hyperdense lesions within the right kidney likely represent haemorrhagic cysts.

The patient proceeded to subtotal colectomy.

MACROSCOPIC DESCRIPTION:Macroscopic description"Bowel": A subtotal colectomy specimen including a segment of large bowel 625mm long, up to 60mm in diameter. Received separately is a short segment of bowel 15mm long and 20mm in diameter. The attached appendix is 50mm long and 5mm in diameter. The pericolic adipose tissue is up to 70mm wide and 20mm thick. At 520mm from the proximal resection and 70mm from the distal resection margin there is an obstructing, indurated and ulcerated tumour measuring 25mm in length and involving the bowel wall lumen circumferentially. At this level the serosal surface is indurated and puckered. The remaining bowel mucosa is unremarkable with no other focal lesions identified. The mesoappendix is 10mm wide. No focal lesions are seen on sectioning the appendix. The proximal resection margin of the colectomy specimen is inked blue and the distal resection margin is inked black. The tumour is 20mm deep, infiltrating the entire bowel wall and extending into the pericolic adipose tissue and abutting the serosal surface. Several lymph nodes are found and processed.

MICROSCOPIC DESCRIPTIONMicroscopic description: In this large bowel wall there is a moderately differentiated adenocarcinoma composed of irregular glands lined by atypical cells with pleomorphic nuclei, prominent nucleoli and frequent mitoses. There is significant mucinous component representing approximately 30% of tumour volume. This comprises pools of mucin with small stranded islands of atypical tumour cells. The carcinoma infiltrates the entire bowel wall also extending to the pericolic adipose tissue. Focally tumour nests and atypical glands are abutting the serosal surface (pT4a). There is a tumour deposit which appears to replace a lymph node. Of the remaining 18 lymph nodes, one includes a small focus of carcinoma, 17 are free of metastatic deposits. Both longitudinal resection margins are well clear. No perineural or lymphovascular space invasion is seen. The lumen of the appendix is fibrosed but otherwise the appendix is unremarkable. The sections from the separate segment of large bowel wall are histologically unremarkable.

DIAGNOSISDiagnosis: Subtotal colectomy: Moderately differentiated adenocarcinoma NOS of the splenic flexure, extending to the serosal surface, with 2 out of 19 lymph nodes involved. AJCC stage IIIB (TNM pT4a N1b MX)