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Grossing & features to report

Authors: Lina Chen, M.B.B.S., M.Sc., M.Med., David K. Driman, M.B.Ch.B.

Deputy Editors-in-Chief: Catherine E. Hagen, M.D., Raul S. Gonzalez, M.D.

Last author update: 15 April 2021

Last staff update: 15 April 2021

Copyright: 2003-2023, PathologyOutlines.com, Inc.

PubMed search: Colon gross features to report

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Table of Contents

Cite this page: Chen L, Driman DK. Grossing & features to report. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colontumorfeaturestoreport.html. Accessed March 22nd, 2023.

Definition / general

This topic describes how to gross specimens obtained from polypectomy and colectomy procedures
Essential clinical history: clinical diagnosis, procedure performed, prior biopsy or procedure

Grossing - polypectomy

Describe: size, color, configuration (sessile or pedunculated), single or multiple pieces (piecemeal polypectomy)
Ink the base or stalk margin if it can be identified
- If stalk present: measure length and diameter of stalk, apply ink to base of stalk
- If stalk not present: look for pale tissue at base of polyp, apply ink to this area
Submit in toto (Am J Clin Pathol 2001;116:336)
- Small polyp: bisect perpendicular to the stalk or base
- Large polyp: for polyps with wide heads not able to fit in a cassette, trim the sides away from the stalk; take section through surgical margin of stalk, submit in one cassette and put the sides in other cassette(s)
- Sectioning protocol based on polyp size (see table 1)

Grossing - endoscopic mucosal resection (EMR) or endoscopic submucosal resection (ESD)

Orientation and ink
- If unoriented, ink the deep and peripheral margins with one color
- If oriented, ink the deep margin and peripheral margins with multiple colors (similar to inking a skin eclipse)
Describe: lesion present or not, size, type, color, shape, borders, distance to all margins
Identify the closest peripheral margin and section along that axis at 2 mm intervals, submit in toto

Grossing - colectomy

Identify the anatomical subsites of the resected bowel and lesion location (see diagram 1 and table 2)
Segmental resection of isolated ascending, descending or sigmoid colon often cannot be distinguished by gross examination
Thus, proper documentation by surgeons is the key

Grossing - colectomy with no tumor

Identify and record the subsites of colon
- Open the bowel along the antimesenteric border using scissors
- Clean the lumen by gently washing out fecal material
- Fix in formalin overnight (ensure the specimen is immersed in an adequate volume of clean formalin)
- Measure and record the dimensions (length and circumferences), length of mesentery and size of omentum if present
- Describe and record any abnormal findings
Sections to submit:
- Sections to submit depend on the pathological findings (IBD, ischemia, volvulus, diverticular disease, arteriovenous malformation, etc.)
- Abnormal areas by taking sections perpendicular to mucosal folds (through bowel wall)
- Resection margins
- Representative sections of other organs present (appendix, terminal ileum, etc.)
- At least one representative section from grossly uninvolved colon
- Lymph nodes
  - Representative lymph nodes (usually one cassette) suffices

Grossing - colectomy with tumor

Identify and record the subsites of colon
Identify the location of the lesion(s) by palpation
Open the bowel along the uninvolved colonic wall using scissors
Clean the lumen by gently washing out fecal material
Ideally, pin the colon on a flat board; immerse in clean formalin, at least overnight
Measure and record the dimensions of the specimen (length and circumferences), length of mesentery and size of omentum if present
Measure and describe the lesion(s)
Measure and record the distance of lesion(s) from margins
Identify and ink the closest mesenteric margin (see Arch Pathol Lab Med 2009;133:1539 and diagram 3)
Identify and ink the colonic radial resection margin if present
- Radial (retroperitoneal) margins are present in the proximal ascending colon and the descending colon
Identify where tumor is close to or extending through a serosal surface and ink any suspicious serosal area with a different color
- Suspicious areas are those areas of serosa that are roughened, granular or appear hypervascular
Inspect the entire bowel for polyps, other lesions or any abnormality
All lymph nodes must be found and submitted in their entirety (must record whether nodes are bisected or trisected and submitted in one block or in multiple blocks)
- Best achieved by removing the fat close to the bowel wall and then using inspection and palpation to identify nodes
- Important to examine the fat that remains adhered to the bowel wall, as this is often a location for small nodes
- At least 12 lymph nodes are needed for accurate staging (Am J Surg Pathol 2002;26:179)
- For more tips of lymph node searching, see Grossing & features to report - lymph nodes

Grossing - total mesorectal excision (TME) specimens

Identify anatomical landmarks and location of tumor by palpation
- Peritoneal reflection is low on the anterior aspect but high on the posterior aspect; the nonperitonealized tissue distal to the reflection is the radial resection margin
- Note that tumors in the upper / proximal rectum will have a serosal covering anteriorly and laterally and a radial margin posteriorly; mid to low / distal rectal tumors have a circumferential radial resection margin beneath the anterior peritoneal reflection
Photograph in fresh state (useful for correlation with imaging and documentation of completeness of mesorectum)
- Anterior aspect
- Posterior aspect
- Other findings (e.g. significant defects)
Open the specimen along the anterior aspect from the top and the bottom, leaving the bowel intact at a level just above and just below the tumor
Place loose gauze (soaked in formalin) into the unopened ends of the bowel
Fix all rectal cancer specimens for 72 - 96 hours in adequate volume of formalin
Measure and record the dimensions of the specimen (length and circumferences)
Evaluation of mesorectum completeness
- Bulk: good, moderate, little
- Surface: smooth or irregular
- Defect (record the depth of defect and extension)
  - None > 5 mm
  - > 5 mm but no visible muscularis propria
  - Down to muscularis propria
- Coning: present or absent
- Completeness of the mesorectum is scored according to the worst area
  - Complete (Cancer 2009;115:3400, J Clin Pathol 2007;60:849) (see gross images)
    - Intact bulky mesorectum with a smooth surface
    - Only minor irregularities of the mesorectal surface
    - No surface defects greater than 5 mm in depth
    - No coning towards the distal margin of the specimen
    - After transverse sectioning, the circumferential margin appears smooth
  - Nearly complete (Cancer 2009;115:3400) (see gross images)
    - Moderate bulk to the mesorectum
    - Irregularity of the mesorectal surface with defects greater than 5 mm but none extending to the muscularis propria
    - No areas of visibility of the muscularis propria except at the insertion site of the levator ani muscles
  - Incomplete (Cancer 2009;115:3400, J Clin Pathol 2007;60:849) (see gross images)
    - Little bulk to the mesorectum
    - Defects in the mesorectum down to the muscularis propria
    - After transverse sectioning, the circumferential margin appears very irregular
Paint the bare area below the peritoneal reflection with ink
Describe any other organs / tissues present as appropriate (e.g. vagina, prostate, bladder, etc.)
Slice through the unopened bowel at 3 - 5 mm intervals
Photograph (see above):
- All rings laid out sequentially from proximal to distal
- Close up photographs of any ring(s) to show significant findings (e.g. defects, tumor close to radial margin, etc.)
Inspect slices to record:
- CRM (circumferential radial margin): smooth, regular, moderately irregular, very irregular
- Extent of tumor
- Closest distance of tumor to the CRM and whether it is anterior, posterior or lateral
- Obviously positive nodes and the distance of any positive node to the CRM
- Examine fat away from tumor for lymph nodes
- Inspect the entire bowel for polyps, other lesions or any abnormality
Sections to submit:
- Tumor (entire tumor if 5 sections or less or 1 section per cm diameter)
  - Deepest point of invasion (at least 2 sections)
  - Relationship to radial margin (at least 2 sections; may be the same as sections showing deepest invasion)
  - Relationship to serosa (at least 2 sections)
  - If no obvious tumor following neoadjuvant treatment (Biomed Res Int 2015;2015:574540):
    - Take at least 5 blocks from scarred area, including deepest point, relationship to radial margin and relationship to serosa
    - If no viable tumour cells are identified microscopically, submit the entire scarred area
    - If no viable tumour cells are found after submitting the entire scarred area, cut through at least three levels for each block
    - If no viable tumour cells are present after the above steps, report as complete pathologic response or ypT0
- Longitudinal resection margins
- Interface with uninvolved bowel
- Relationship with other organs (if present)
- Uninvolved bowel
- Appendix, terminal ileum, cecum and ileocecal value, if present
- Any other abnormalities
- All the lymph nodes submitted in their entirety (must record whether nodes are bisected or trisected in 1 block or in multiple blocks)

Features to report for adenocarcinoma

Editorial note
"Mandatory" means for accreditation purposes by the American College of Surgeons Commission on Cancer
"Recommended" means suggested by the literature
Protocol may improve quality of pathology report (Colorectal Dis 2011;13:e33)
Features to report by organization:

Colonic biopsy - mandatory to report

Biopsy site
Histologic type

Colonic biopsy - recommended but not required to report

Tumor size
Histologic grade
Depth of invasion (if identifiable)
Lymphovascular invasion
Tumor budding
Type of polyp it arises from (if applicable)

Polypectomy - mandatory to report

Tumor site
Specimen integrity (intact or fragmented)
Polyp size
- Maximum dimensions of intact specimen and intact polyp are mandatory
Type of polyp
Histologic type
Histologic grade
Maximum size of invasive component
Tumor thickness - vertical dimension
Tumor extension
Distance of invasive carcinoma from margin / polyp base
Involvement of mucosal / lateral margin by invasive carcinoma or dysplasia
Lymphovascular invasion
- Small vessel
- Large vessel: intramural or extramural
Perineural invasion
Ancillary studies performed (depending on local protocols)
- Microsatellite instability, immunohistochemistry for mismatch repair proteins, mutational analysis (required in some places in patients younger than 70, others in all patients)

Polypectomy - recommended but not required to report

Aggregated dimensions of fragmented polyp or maximum dimensions of largest piece for fragmented polyp
Maximum width of invasion
Tumor budding: low, intermediate or high
Additional findings

Colorectal resection for tumor - mandatory to report

Specimen type
Number of tumors (for multiple primary tumors, each tumor requires a complete report)
Tumor site(s)
Tumor location relative to anterior peritoneal reflection for rectal tumors: entirely above, below or straddling
Tumor size
Macroscopic tumor perforation
Macroscopic intactness of mesorectum (required only for rectal tumors)
Histologic type
Histologic grade
Tumor extension
Margins
- Involved by invasive carcinoma or not
- Involved by low or high grade dysplasia or not
- If all margins are negative, specify closest margin and distance of invasive carcinoma from this margin
- Distance of tumor from CRM (required only for rectal tumors)
Lymphovascular invasion: present or not identified
- Small vessel
- Large vessel: intramural or extramural
Perineural invasion
Treatment effect
- No known presurgical therapy
- Present
  - Complete response: no viable cancer cells (can have acellular mucin present)
  - Near complete response: single cells or rare small groups of cancer cells
  - Partial response: more than single cells or rare small groups of residual cancer with tumor regression
  - Poor or no response: extensive cancer with no evident tumor regression
Tumor deposits (absence / presence and numbers)
Regional lymph node: number of examined and number of involved
Ancillary studies performed (depending on local protocols)
- Microsatellite instability, immunohistochemistry for mismatch repair proteins, mutational analysis (required in some places in patients younger than 70, others in all patients)

Colorectal resection for tumor - recommended but not required to report

Margin:
- Rectum cancer: distance of tumor from negative distal margin
Tumor budding: number of buds in 1 hotspot field (0.785 mm²)
- Low score: 0 - 4
- Intermediate score: 5 - 9
- High score: 10 or more
Type of polyp in which invasive carcinoma arose
Additional pathologic findings (e.g. adenoma, ulcerative colitis, Crohn’s disease, diverticulosis, etc.)
Checklists: Michigan Cancer Consortium

Gross description

Gross images

Images hosted on other servers:

Complete and incomplete mesorectum

Sample gross description report

Polypectomy:

The specimen is received in a properly labeled container with the patient's identifiers and accession number, designated as sigmoid polyp
Specimen: brown polypoid piece(s)
- Number: 1
- Size: 1.2 cm
- Stalk(s): not identified
- Site(s) of attachment: inked
Section code (entirely submitted):
- (A1) trisected

Colectomy:

Sample 1:

The specimen is received in a properly labeled container with the patient's identifiers and accession number, designated as right hemicolectomy
Specimen:
- Terminal ileum: 5.5 x 4.7 cm (length x circumference proximal margin)
- Appendix: 5.5 x 0.6 cm (length x greatest diameter)
- Colon: 13.5 x 8.4 cm (length x circumference distal margin)
- Proximal margin received stapled
- Distal margin received stapled
- Pericolic soft tissue: 8.0 cm in depth
Number of tumors: 1
Location(s): within the cecum at the appendiceal orifice
Configuration: polypoid
Size: 2.2 x 1.2 x 0.4 cm (length x width x thickness)
Distance from longitudinal margins: 4.5 cm; 12.5 cm (proximal; distal)
Extension into pericolic / rectal tissue: absent
Extension into other organs or tissues: absent
Tumor perforation: absent
Serosa underlying tumor:
- Unremarkable
- Distance of tumor to closest serosa: 0.5 cm
Radial margin:
- Closest distance of direct tumor extension to radial margin: 4.2 cm
Lesions in nontumoral mucosa: diverticula
Lymph nodes: within the pericolic soft tissue are multiple possible lymph nodes (0.2 - 0.8 cm)
Ink code:
- Colon radial margin: black
- Serosal surface: blue
- Proximal and distal resection margins: black
Section code (representative sections):
- (A1 - A5) entire polypoid lesion with closest serosa
- (A6) closest radial margin
- (A7) proximal margin
- (A8) distal margin
- (A9) appendix
- (A10) diverticulum
- (A11 - A13) multiple intact lymph nodes in each
- (A14 - A16) 1 lymph node in each

Sample 2:

The specimen is received in a properly labeled container with the patient's identifiers and accession number, designated as rectosigmoid resection
Specimen:
- Sigmoid colon and rectum 24.5 x 6.0 x 7.5 cm (length x circumference proximal margin x circumference distal margin)
- Proximal margin received stapled
- Distal margin received stapled
- Pericolic and perirectal soft tissue up to 4.5 cm in depth
Number of tumors: 1
Location(s): sigmoid colon
Configuration: annular / circumferential
Size: 4.1 x 2.2 x 1.5 cm (length x width x thickness)
Distance from longitudinal margins: 13.0 cm; 6.5 cm (proximal; distal)
Extension into pericolic / rectal tissue: present
Extension into other organs or tissues: absent
Tumor perforation: absent
Serosa underlying tumor:
- Puckered with fibrous adhesions
- Distance of tumor to closest serosa: 0.0 cm
Radial margin:
- Closest distance of direct tumor extension to radial margin: 1.2 cm
- Closest distance of involved lymph node or tumor nodule to radial margin: 0.0 cm
- Closest margin is mesenteric (vascular tie)
Lesions in nontumoral mucosa:
- Polyp(s): 2 sessile polyps (0.3 and 0.6 cm) immediately distal to the mass
- Diverticula
Lymph nodes: within the pericolic fat are multiple possible lymph nodes (0.2 - 2.8 cm)
Ink code:
- Colon radial margin: black
- Serosal surface: blue
- Proximal and distal resection margins: black
Section code (representative sections):
- (A1 - A3) mass and closest radial margin
- (A4 - A6) mass and deepest point of invasion
- (A7 - A8) mass and closest overlying serosa
- (A8) proximal margin
- (A9) distal margin
- (A10) 1 polyp
- (A11 - A12) 1 polyp, bisected
- (A13) lymph node abutting radial margin
- (A14 - A16) multiple intact lymph nodes in each
- (A17 - A20) 1 lymph node in each
- (A20 - A21) 1 lymph node
- (A22 - A25) 1 lymph node

Sample 3:

The specimen is received in a properly labeled container with the patient's identifiers and accession number, designated as rectosigmoid resection
Specimen:
- Sigmoid colon and rectum 13.0 x 2.8 x 7.0 cm (length x circumference proximal margin x circumference distal margin)
- Proximal margin received stapled
- Distal margin received stapled
- Pericolic and perirectal soft tissue up to 6.0 cm in depth
- Mesorectum: good bulk, intact with smooth surface
- Defects: none > 5 mm
- Coning: none
Number of tumors: 1
Location(s):
- Rectum
  - Tumor at anterior peritoneal reflection
  - Tumor 6.5 cm distal to posterior peritoneal reflection
Configuration: annular / circumferential
Size: 3.5 x 3.5 x 0.7 cm (length x width x thickness)
Distance from longitudinal margins: 8.0 cm; 1.2 cm (proximal; distal)
Extension into pericolic / rectal tissue: present
Extension into other organs or tissues: absent
Tumor perforation: absent
Serosa underlying tumor:
- Unremarkable
- Distance of tumor to closest serosa: 0.2 cm
Radial margin:
- Closest distance of direct tumor extension to radial margin: 0.4 cm
- Closest radial margin is left lateral
- Radial margin on cross section is smooth
Lesions in nontumoral mucosa: diverticulum
Lymph nodes: multiple possible tan lymph nodes (0.5 to 2.0 cm) identified
Ink code:
- Colon radial margin: black
- Rectal posterior radial margin: black
- Rectal anterior radial margin: green
- Serosal surface: blue
- Proximal and distal resection margins: black
Section code (representative sections):
- (A1) proximal margin
- (A2) distal margin with tumor
- (A3 - A4) tumor, closest to serosa
- (A5) tumor, closest to radial margin
- (A6 - A8) tumor, deepest point of invasion
- (A9) diverticulum
- (A10 - A13) 3 possible lymph nodes in each
- (A14) 2 possible lymph nodes
- (A15 - A17) 1 possible lymph node in each
- (A18 - A20) multiple possible lymph nodes in each

Diagrams / tables

Table 1: sectioning protocol based on polyp size

Polyp Size	Sectioning Protocol
Smaller than 0.4 cm	No sectioning
0.4 - 0.8 cm	Bisect; place in 1 cassette
0.9 - 1.2 cm	Trisect by shaving two sides off central section with stalk; place central section in separate cassette
Larger than 1.2 cm	More than 3 sections as appropriate

Images hosted on other servers:

Anatomic subsites of colon and rectum (table 2)

Anatomic subsites of the colon

Mesenteric / radial margin

T category staging

Regional lymph nodes

Additional references

Lester: Manual of Surgical Pathology: Expert Consult, 3rd Edition, 2010, Arch Pathol Lab Med 2019;143:869, J Clin Pathol 2007;60:849

Board review style question #1

You are grossing a subtotal colectomy specimen for a biopsy proven colon adenocarcinoma. You find 50 lymph nodes with 15 of them larger than 1 cm in size. Which of the following will be the most appropriate sections to submit?

All lymph nodes submitted in their entirety
Lymph nodes larger than 1 cm submitted in their entirety
Representative sections of all lymph nodes
Representative sections of lymph nodes larger than 1 cm and in toto of lymph nodes smaller than 1 cm

Board review style answer #1

A. All lymph nodes submitted in their entirety

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Reference: Colon - Grossing & features to report

Board review style question #2

You are grossing a TME specimen and found a defect on the mesorectum under the peritoneal reflection down to the muscularis propria. How would you report on the macroscopic evaluation of mesorectum?

Cannot be determined
Complete
Incomplete
Near complete

Board review style answer #2

C. Incomplete

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Reference: Colon - Grossing & features to report

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