Sigmoid colon adenocarcinoma

Case contributed by Dr Bruno Di Muzio

Presentation

Represents with generalised abdominal pain, vomiting/dry retching/anorexia for 5 days.

Patient Data

Age: 53 years
Gender: Female
CT

CT Abdomen and pelvis

There is a focal segment of sigmoid wall thickening characterising a solid enhancing mass that extends for 5.5 cm with a 4.0 cm width. This causes diffuse upstream colonic distension with faecal loading. A few adjacent lymph nodes are noted, measuring less than 1 cm in their short diameter. Small amount of free fluid in the pelvis. No free gas in the abdominal cavity. Small bowel is unremarkable. The liver demonstrates a subcapsular ill-defined hypodense nodule measuring 2.7 cm in the segment VI and a tiny 4.7 mm hypodense lesion in the segment IVB, which is too small to characterise. The gallbladder, pancreas, and adrenal glands are unremarkable. Kidneys have normal size and enhancement; there is a tiny non-obstructive calculus in the left kidney upper moiety. No hydronephrosis. Apart from a 1.5 cm right para-aortic lymph node, the retroperitoneum is unremarkable. No suspicious bone lesions. Pleural bases are clear. Conclusion: Features favouring a colonic carcinoma in the sigmoid causing at least partial obstruction and retained upstream faecal loading. Liver lesion in the segment VI is indeterminate within this protocol but may represent haemangioma, and multiphase CT is recommended to characterise.

Case Discussion

The patient underwent to a partial colectomy:

MICROSCOPIC DESCRIPTION: Sections from the sigmoid show an ulcerated moderately differentiated adenocarcinoma composed of irregular glands with a complex cribriform architecture, many with central necrosis and associated calcification. Malignant glands focally infiltrate the pericolic fat and extend beyond the muscularis propria to within 5mm of the serosal surface. The malignant cells have pleomorphic vesicular nuclei and prominent nucleoli. Mitotic figures are frequent. The stroma is desmoplastic and the tumour is associated with a moderate to heavy lymphocytic and neutrophilic infiltrate. Perineural and lymphovascular invasion are not identified. One of twenty eight lymph nodes is involved by metastatic tumour.

DIAGNOSIS: Sigmoid colon: * Moderately differentiated adenocarcinoma, invading through muscularis propria into pericolic tissue (pT3) - Obstructing circumferential tumour 60mm in length - Clear of serosa - Well clear of margins - No perineural or lymphovascular invasion - 1 our of 28 lymph nodes involved by tumour (1/28). - pT3 pN1c AJCC stage IIIB.

IMMUNOHISTOCHEMISTRY Mismatch repair proteins MLH1 POSITIVE PMS2 POSITIVE MSH2 POSITIVE MSH6 POSITIVE There is normal expression of mismatch repair proteins in tumour cells, indicating that the tumour is mismatch repair proficient (microsatellite stable, MSS). BRAF V600E NEGATIVE

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Case information

rID: 52101
Case created: 22nd Mar 2017
Last edited: 18th Jul 2017
Tag: rmh
Inclusion in quiz mode: Included

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