Colon, Tumor

Introduction

The are a few questions to be addressed:

1. Is this tumor primary or metastatic?
2. What is the depth of invasion?
3. Are there metastases?
4. Are the margins free of tumor?
5. Is there any underlying mucosal pathology (IBD)?

Fresh Handling

1. Measure: Length and diameter of specimen, staple lines, terminal ileum and appendix if present, mesentery.
2. Ink proximal, distal, and deep margins (of tumor) of resection.
3. Open bowel; avoid cutting into tumor, if possible. Gently remove stool and or blood with saline rinse.
4. Photograph the opened specimen
5. Pin down on corkboard and fix overnight. Cut a few sections into the tumor and the mesenteric fat to allow better fixation. Consider tissue banking before fixing!

Grossing In

1. Identify type of resection
2. Describe measurements as above.
3. Tumor characteristics:
   1. Size (including thickness), extent around bowel circumference, shape (fungating, flat, ulcerating), presence of necrosis or hemorrhage, extent through bowel wall, serosal involvement, satellite nodules, evidence of blood vessel invasion, invasion of adjacent organs.
   2. Distance of tumor to pectinate line, peritoneal reflection, and each margin of resection as applicable.
4. Other lesions in bowel and appearance of uninvolved mucosa; note presence or absence of associated polyps.
5. Estimate the number of lymph nodes found, and whether they appear to be involved by tumor, or not. Note size of largest node.
6. Summary of sections:
   1. Sections of tumor (3), including junction of carcinoma with normal mucosa on at least one, and full depth (with inked margin), including serosa on at least two sections.
   2. If specimen is obtained for a presumed adenoma, then take sections so that the relationship of the stalk to the bowel wall is maintained.
   3. Submit the entire head and stalk of the adenoma.
   4. Other lesions, if any.
   5. Margins of resection, proximal and distal.
   6. Appendix, if included.
   7. Lymph nodes (separate by contiguous to the tumor, proximal, and distal), remember you must get at least 10. Measure the enlarged lymph nodes and note if they seem involved by tumor. If so, a representative section is sufficient. Submit all other nodes entirely.

Sample Dictation

Specimen #--- is received fresh, labeled with the patient’s name and medical record number, designated “--------“ and consists of a partial colectomy specimen measuring _ cm in length and _ cm in circumference, with a maximum wall thickness of _ cm. The peri-colonic adipose tissue measures – cm.

The specimen is received oriented with a suture marking the proximal stapled/closed/open end/margin, measuring _ cm and the distal stapled/closed/open end/margin, measuring _ cm. OR The specimen is received unoriented with no specific suture designations. One stapled/closed/open ileal end/margin, measures _ cm and the second stapled/closed/open colonic end/margin, measures _ cm.

The external serosal surface of the specimen, inked entirely black is grossly unremarkable, smooth and glistening, with no grossly apparent lesions. OR The external serosal surface of the specimen, inked entirely black is dull, irregular with adhesions, but shows no grossly apparent lesions. OR The external serosal surface of the specimen, inked entirely black, is indurated, retracted, with nodular lesions/ tumor implants, measuring _ cm, present in the proximal/ distal large bowel, _cm from the proximal/one stapled/closed/open end/margin and _ cm from the distal/second stapled/closed/open end/margin. OR The external serosal surface of the specimen, inked entirely black, grossly shows invasion of the tumor through the wall, (shows an area of perforation), measuring _ cm, present in the proximal/ distal large bowel, ­ cm from the proximal/one stapled/closed/open end/margin and ­ cm from the distal/second stapled/closed/open end/margin.

The specimen is opened along its anti-mesenteric aspect to reveal a solitary, round/ovoid/irregular/exophytic/polypoid/ulcerating/infiltrative/diffuse, well/poorly circumscribed lesion, with irregular/rolled/raised/serpentine/puckered margins, measuring ­ cm, ­_ in color, soft/firm/hard in consistency, with a homogenous/heterogenous, irregular/smooth, fleshy/variegated cut surface, with/without areas of hemorrhage and necrosis, { Solitary, firm, tan-red lesion, measuring – cm, with raised, heaped up serpentine borders and a central ulcerated bed }, located in the proximal/ distal large bowel, _ cm from the proximal/one stapled/closed/open end/margin and _ cm from the distal/second stapled/closed/open end/margin. The lesion is situated _ cm from the nearest radial/circumferential margin and on serial sectioning (choose one):

Is predominantly an intra-mucosal lesion, not showing invasion into the submucosa, present _ cm from the nearest deep inked serosal surface.

Shows invasion into but not through the muscularis propria, present _ cm from the nearest deep inked serosal surface.

Shows invasion into and through the muscularis propria, but does not appear to be transmural, present _ cm from the nearest deep inked serosal surface.

Shows invasion into and through the muscularis propria, appears to be transmural, and grossly corresponds to the previously mentioned area of perforation, noted on the serosal surface, present at/ _ cm from the nearest deep inked serosal surface.

The lesion occupies --% of circumference of bowel, with the minimal luminal diameter at the site of the lesion measuring _ cm, with/without proximal bowel dilatation (measuring – cm in maximum circumference), and with/without bowel perforation. The specimen on serial sectioning shows no other grossly apparent lesions. The adjacent uninvolved colonic mucosa is smooth, glistening and grossly unremarkable. The peri-colonic soft tissue is palpated and dissected for potential lymph nodes. Representative sections of the specimen are submitted as follows: Staple line/margin #1 as _ and _; staple line/margin #2 as _ and _; representative sections of the tumor (including inked serosal margin and transition to adjacent mucosa) as _ through _; additional mucosal lesions (polyps) as _; a representative section of unremarkable mucosa as _; appendix as _; potential lymph nodes as _ through _.

Review and Signout

The following should be included in the histologic description:

• Degree of differentiation.
• Depth of invasion, by layer.
• Association (if any) with adenomatous precursor lesion.
• Lymph node number and number of positive nodes.
• Margins of resection.
• Presence of vascular or lymphatic invasion.
• Associated lesions, if any.

Sample diagnostic lines

1. Colon, right, hemicolectomy:
2. Colon and ileum, hemicolectomy:

Adenocarcinoma, XX cm, (well, moderately, poorly) differentiated, invasive (into lamina propria without involvement of muscularis propria vs. into but not through muscular propria vs. through muscularis propria into the subserosal adipose tissue without serosal involvement vs. invasive through serosa), (with lymphovascular invasion vs. no lymphovascular invasion identified), see note.

Proximal (ileal vs. colonic) and distal colonic resection margins free of tumor.

X lymph nodes, no carcinoma identified (0/X). vs Metastatic adenocarcinoma in X of Y lymph nodes (X/Y).

Appendix with no specific pathologic change.

Include staging in a note or synoptic.

A word on Lynch syndrome or hereditary non-polyposis colon cancer (HNPCC) syndrome:

According to the American College of Gastroenterology guidelines for colorectal cancer screening 2009 (Am J Gastroenterol. 2009 Mar;104(3):739-50), “Patients who meet the Bethesda criteria should undergo microsatellite instability testing of their tumor or a family member’s tumor and/or tumor immunohistochemical staining for mismatch repair proteins (Grade 2 B)”. See the Bethesda criteria below, usually when these are met your attending will order the immunohistochemical stains for DNA mismatch repair proteins (MLH1, MSH2 and MSH6), or occasionally the microsatellite instability molecular testing.

The Revised Bethesda Guidelines for testing colorectal tumors for microsatellite instability (MSI) (JNCI 2004 96(4):261-268):

Tumors from individuals should be tested for MSI in the following situations:

1. Colorectal cancer diagnosed in a patient who is less than 50 years of age.
2. Presence of synchronous, metachronous colorectal, or other HNPCC-associated tumors, regardless of age.
3. Colorectal cancer with the MSI-H histology diagnosed in a patient who is less than 60 years of age.
4. Colorectal cancer diagnosed in one or more first-degree relatives with an HNPCC-related tumor, with one of the cancers being diagnosed under age 50 years.
5. Colorectal cancer diagnosed in two or more first- or second-degree relatives with HNPCC-related tumors, regardless of age.

• HNPCC-associated tumors include colorectal, endometrial, stomach, ovarian, pancreas, ureter and renal pelvis, biliary tract, and brain (usually glioblastoma as seen in Turcot syndrome) tumors, sebaceous gland adenomas and keratoacanthomas in Muir–Torre syndrome, and carcinoma of the small bowel (48).
• MSI-H = microsatellite instability–high in tumors refers to changes in two or more of the five National Cancer Institute-recommended panels of microsatellite markers.
• MSI-H histology: Presence of tumor infiltrating lymphocytes, Crohn’s-like lymphocytic reaction, mucinous/signet-ring differentiation, or medullary growth pattern.
• There was no consensus among the Workshop participants on whether to include the age criteria in guideline 3 above; participants voted to keep less than 60 years of age in the guidelines.

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