Colorectal tumour
Background
Various resection procedures are used to remove tumours of the large bowel and rectum:1-5
Right hemicolectomy is resection of the ascending colon; when part of the transverse colon is also resected, it may be referred to as an extended hemicolectomy. Left hemicolectomy is resection of the descending colon.
Right hemicolectomy includes terminal ileum, caecum, appendix (unless removed in earlier surgery) and segment of ascending colon up to the hepatic flexure.
Left hemicolectomy includes transverse colon and descending colon from the splenic flexure to the sigmoid colon covered by serosa and within visceral peritoneum.
Transverse colon is the only segment with omentum. Transverse colectomy, from the hepatic to the splenic flexures, is also possible, though uncommon.
Rectosigmoid resection; where the transition from sigmoid colon to rectum can be identified by fusion of sigmoid longitudinal taenia coli with longitudinal muscle of rectum. Sigmoid colon is completely covered by peritoneum but rectum is only covered by peritoneum on anterior and lateral sides in upper two thirds; there is no peritoneum covering the lower third.
An anterior resection consists of rectum or rectosigmoid with anastomosis that leaves the anus intact. A high anterior resection is further towards the sigmoid end of the rectum. A low anterior resection contains more rectum and ultralow is a resection of rectum towards the anus.
Hartmann's procedure is resection of rectosigmoid where closure of the remaining rectum is necessary with formation of an end colostomy.
Abdominoperineal resections (AP) include perianal skin, anus and rectum, where very low tumour is located at or near the anal sphincter. Occasionally they will also include sigmoid colon.
Record the patient identifying information and any clinical information supplied together with the specimen description as designated on the container. See overview page for more detail on identification principles.
- No
- Non-routine fixation (not formalin), describe.
- Yes
- Special studies required, describe.
- Ensure samples are taken prior to fixation.
- Not performed
- Performed, describe type and result
- Frozen section
- Imprints
- Other, describe
See general information for more detail on specimen handling procedures.
Inspect the specimen and dictate a macroscopic description.
External Inspection
Orientate and identify the anatomical features of the specimen.
Record additional orientation or designation provided by operating clinician:
- Absent
- Present
- Method of designation (e.g. suture, incision)
- Featured denoted
Photograph the intact specimen if required.
Describe the following features of the specimen:
Procedure
Record as stated by the clinician.
- Right hemicolectomy
- Extended right hemicolectomy
- Transverse colectomy
- Left hemicolectomy
- Sigmoid colectomy
- Anterior resection
- Abdominoperineal resection
- Proctocolectomy
- Total colectomy with ileorectal anastomosis
- Hartmann’s procedure
- Total mesorectal excision (TME)
- Other procedure(s), describe
Anatomical components included (more than one may apply) and dimensions (mm)
- Specimen length (in total)
Describe and measure the anatomical components present.
- Terminal ileum, length
- Caecum
- Colon, length
- Rectum
- Appendix, in two dimensions
- Omentum, in three dimensions
- Other tissues present, describe and measure in three dimensions
Beware of misleading labels such as "sigmoid" when actually rectosigmoid. Check clinical notes for exact resection type.5
Specimen integrity
- Intact
- Disrupted, describe
Tumour perforation
- Absent
- Present
- Distant from the tumour
- At the tumour site
Tumour perforation is defined as a macroscopically visible defect through the tumour such that the bowel is in communication with the external surface (serosa) of the intact resection specimen.2
Examine the outer surface before opening. Look for areas of tumour involvement, distant tumour deposits and lymph node involvement. Check carefully for tumour perforation in the unopened specimen as soon as possible on arrival in the laboratory.6 It is important to distinguish, where possible, between perforation occurring at the time of surgery and perforation before surgery. Perforation of the proximal bowel as a result of a distal obstructing tumour must not be recorded as tumour perforation, but should be noted.2 Serosal involvement is likely at or adjacent to peritoneal reflections, especially in the clefts adjacent to the bowel wall. Be suspicious of granular, dull or haemorrhagic areas of serosa.2,4
Dissection
The lumen of specimens should be gently rinsed on arrival in laboratory.
Open along antimesenteric border or nearest lateral incision longitudinal line that leaves tumour intact.
Specimens can be pinned out on board if desired, around the tumour or along entire length and left to fix adequately before further dissection. 8 Alternatively, particularly in the case of circumferential tumours, open the specimen anteriorly down to the level of the tumour from both ends. Leave the tumour segment unopened and place a wick of formalin soaked paper or gauze into the unopened lumen to aid fixation. Rectal tumours should be left intact to fix for optimal assessment of the non-peritonealised resection margin. The relationship of the tumour, nodes, or extramural tumour deposits to the non-peritonealised resection margin must be assessed and measured.
After sufficient fixation, paint the relevant surgical margins with ink and record the colours applied.
Do not ink the serosal surface as it is not a resection margin. Inking of the serosa may result in misinterpretation of serosal surface involvement as representing margin involvement of tumour adjacent to the painted aspect. It can also mask the presence of tumour cells on the serosal surface.2,5
Internal Inspection
Describe the internal appearance including the following items:
Tumour
- Absent see also Colorectal non-tumour
- Present
- Solitary
- Multiple, number; if more than one tumour, designate and describe each tumour separately
Tumour description
For each tumour, describe:
Size (mm)
- Maximum dimension
- Penetration into wall
Site
- Ileocaecal valve
- Caecum
- Ascending colon
- Hepatic flexure
- Transverse colon
- Splenic flexure
- Descending colon
- Sigmoid colon
- Rectosigmoid junction
- *Rectum
- Not known
Serosal/peritoneal involvement
- Absent
- Suspicious
- Present
- Tumour invades to the peritoneal surface
- Tumour has formed nodule(s) discrete from the tumour mass along the peritoneal surface
Distance to margins (mm)
- Distance of tumour to nearest cut end (longitudinal) proximal or distal margin
- Distance of tumour to the non-peritonealised circumferential margin
Involvement of other tissues
- Absent
- Present, specify tissue involved, location of adherence and distance of tumour to any surgical margin
*Rectal tumours
Describe the following features also:
Tumour relationship to anterior peritoneal reflection
- Entirely above
- Astride
- Entirely below
Intactness/integrity of mesorectum1,2
- Incomplete (grade 1)
- Nearly complete (grade 2)
- Complete/intact (grade 3)
If AP resection
- Distance from dentate line (mm)
Polyps
- Absent
- Present, describe
- Configuration
- Size, maximum dimension (mm)
Any other abnormalities
Retrieved from resection specimen
- Describe site(s)
- Number retrieved
Separately submitted
- For each specimen container, record specimen number and designation
- Collective size of tissue in three dimensions (mm)
- Number of lymph nodes submitted
- Maximum diameter of each (mm)
- For each specimen container, record specimen number and designation
- Collective size of tissue in three dimensions (mm)
Submit all available tissue.
Note photographs taken, diagrams recorded, ink or marks used for identification.
Processing
Dissect the specimen further and submit sections for processing according to the diagram provided.1,2
When adequately fixed, serially section the tumour in 3-4mm intervals and lay out the sequential slices. As a general rule, sections should be taken at 90 degrees (perpendicular) to the mucosal fold of the colon.2
Submit representative sections of:
Tumour, three or more sections demonstrating:1,2
- Maximum spread through wall
- Interface with non-neoplastic mucosa (required for MLH-1 and MSH-2 immunohistochemistry)
- Relationship to non-peritonealised margin
- Sections of serosa if close to tumour 4
- Sections from any area of perforation
- Sections from areas suspicious for extramural venous invasion
Submit all lymph nodes.
In post neoadjuvant rectal specimens, residual tumour may be difficult to identify macroscopically. Submit at least five blocks from the scarred area indicative of the original tumour site. The entire tumour site may require processing if residual tumour is not seen microscopically in initial sections.1,2
Fine pale lines seen at the base of tumour may indicate extramural venous invasion. Tangential sections of this area may assist in its identification.2
Record details of each cassette.
An illustrated block key similar to those provided below may be useful.
Block allocation keys
|
Cassette id
|
Site
|
No. of pieces
|
|
A
|
Colonic and ileal margins
|
|
|
B
|
Apical margin or lymph node
|
|
|
C
|
Appendix
|
|
|
D-G
|
Tumour to deepest point of invasion and/or non-peritonealised margin/serosa
|
|
|
H+
|
Lymph nodes
|
|
|
Cassette id
|
Site
|
No. of pieces
|
|
A
|
Margins; separate blocks are recommended if margins are specified
|
|
|
B
|
Apical margin or lymph node
|
|
|
C-E
|
Tumour to deepest point of invasion and/or non-peritonealised margin/serosa
|
|
|
F+
|
Lymph nodes
|
|
|
Cassette id
|
Site
|
No. of pieces
|
|
A
|
Proximal margin
|
|
|
B
|
Distal margin
|
|
|
C-G
|
Tumour to deepest point of invasion and/or non-peritonealised margin/serosa
|
|
|
H+
|
Lymph nodes
|
|
Acknowledgements
Dr Ian Brown for his contribution in reviewing and editing this protocol.
References
-
Eckstein R, Ackland S, Brown I, Ellis D, Hawkins N, Hicks S, Hunter A, Kneebone A, Ruszkiewicz A and Yeong ML.
Colorectal cancer structured reporting protocol, The Royal College of Pathologists of Australasia, Surry Hills, NSW, 2012.
-
-
-
-
Lester SC. Manual of Surgical Pathology, Saunders Elsevier, Philadelphia, 2010.
-
-
Cross SS, Bull AD and Smith JH. Is there any justification for the routine examination of bowel resection margins in colorectal adenocarcinoma?
J Clin Pathol 1989;42(10):1040-1042.
-
Richards CJ and West KP. Rapid turnaround in histopathology is not appropriate for colorectal carcinoma resections.
J Pathol 1998;186(suppl):29A.
-
Adam U, Mohamdee MO, Martin IG, Scott N, Finan PJ, Johnston D and et al. Role of circumferential margin involvement in the local recurrence of rectal cancer.
Lancet 1994;344:707-711.