Blocks for Histology

Ulceroinflammatory conditions (Figure 5.8)

• sample by circumferential transverse sections the proximal and distal limits of resection.

• sample macroscopically normal bowel.

• sample representative longitudinal blocks (a minimum of six) of any focal abnormality that is present to include its edge and junction with the adjacent mucosa, e.g., ulceration, stricture, fistula, perforation, pseudomembranes, inflammatory polyps, serosal adhesions or constriction bands. Also

- CIBD: sequential labelled samples at 10 cm intervals from caecum to anus and additional blocks from any unusual nodular or sessile abnormality (DALM).

Sigmoid colon and mesentery

Sigmoid colon and mesentery

Figure 5.9. Rectal carcinoma. The upper anterior rectum is invested in peritoneum. The anterior mesorectum is thinner (0.75-1 cm) than the posterior mesorectum (1.5-3 cm). Cut the resection specimen into multiple serial transverse slices about 3-4 mm thick. Blocks for histology are:

Above the reflection


tumour, rectal wall and serosa


tumour, rectal wall and serosa tumour, rectal wall and mesentery

At the reflection


tumour, rectal wall and serosa tumour, rectal wall and mesorectum

Below the reflection


tumour, rectal wall and mesorectum


distance (mm) of the deepest point of continuous tumour extension to the nearest point of the painted CRM


distance (mm) of the deepest point of discontinuous tumour extension (or in a lymphatic, node or vessel) to the nearest point of the painted CRM

Reproduced with permission from Allen DC. Histopathology Reporting: Guidelines for Surgical Cancer. Springer-Verlag: London, 2000.

- ischaemia: sample the mesenteric vessels. • sample mesenteric lymph nodes and any other structures, e.g., appendix or terminal ileum.

Neoplastic conditions (Figure 5.9)

• sample the nearest longitudinal resection margin if tumour is present to within < 3 cm of it.

• sample macroscopically normal bowel and representative blocks of other mucosal lesions that are present, e.g., adenomatous polyps (if multiple, particularly those > 1 cm diameter).

• serially section the bulk of the tumour transversely at 3-4 mm intervals.

• lay the slices out in sequence and photograph.

• note and measure the relationship of the deep aspect of the tumour to the nearest site orientated point of the serosa and the CRM. Note serosal tumour perforation or CRM involvement (< 1 mm).

• sample (four blocks minimum) tumour and wall to demonstrate these relationships. With bulky mesentery/mesorectum the block may have to be split and appropriately labelled for loading in the cassettes.

• count and sample all lymph nodes and identify a suture tie limit node. Take care to count the nodes in the tumour slices and also those in the mesentery away from the tumour, e.g., sigmoid mesocolon in a rectal cancer.

• sample multifocal serosal seedlings as indicated by inspection and palpation.

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  • sago
    What is mesocolon seedling?
    2 years ago

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