Colon

General

Grossing & features to report


Deputy Editors-in-Chief: Catherine E. Hagen, M.D., Raul S. Gonzalez, M.D.
Lina Chen, M.B.B.S., M.Sc., M.Med.
David K. Driman, M.B.Ch.B.

Topic Completed: 15 April 2021

Minor changes: 15 April 2021

Copyright: 2003-2021, PathologyOutlines.com, Inc.

PubMed search: Colon gross features to report

Lina Chen, M.B.B.S., M.Sc., M.Med.
David K. Driman, M.B.Ch.B.
Page views in 2020: 1,022
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Cite this page: Chen L, Driman DK. Grossing & features to report. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colontumorfeaturestoreport.html. Accessed October 28th, 2021.
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
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 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

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?

  1. All lymph nodes submitted in their entirety
  2. Lymph nodes larger than 1 cm submitted in their entirety
  3. Representative sections of all lymph nodes
  4. 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

Comment Here

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?

  1. Cannot be determined
  2. Complete
  3. Incomplete
  4. Near complete
Board review style answer #2
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