Colon, Non-Tumor

Introduction

Typical specimens received for “colonic resection” include:

• Right colectomy: The specimen consists of a portion of terminal ileum, cecum, appendix (unless removed by previous surgery, which should be documented), and a certain length of ascending colon. When opened, the ileocecal valve serves as the limit between the terminal ileum and the cecum.
• Partial colectomy: This could include any segment of the colon (ascending, transverse, descending). The transverse colon is the only portion that has omentum. It is not possible to grossly distinguish isolated portions of the ascending, descending and sigmoid colon.
• Total colectomy with ileo-anal pull-through reconstruction: The specimen consists of terminal ileum to rectum. The anal spinchter is preserved, but the rectal mucosa is dissected along the submucosal plane, and may be submitted as a separate specimen.
• Proctocolectomy: Includes anal canal, rectum and possible sigmoid colon.
• Abdominoperineal resection: This specimen includes perianal skin, anal canal and rectum (possibly also sigmoid), it is used to resect tumors of the low rectum or anal canal. These last two will be described in the rectum section.

In any case, whether the underlying problem is an inflammatory, infectious, traumatic or ischemic condition, the questions remain the same:

1. Why was the procedure done?
2. Is there any pathology?

If the surgery is performed for IBD, there are a few specific questions to be addressed:

1. What is the nature of the IBD (Crohn’s vs UC)?
2. Is there dysplasia?
3. Is there carcinoma?

Fresh Handling

The goal of systematic specimen processing is to allow accurate reconstruction of the anatomic findings. Documentation of the anatomic distribution of the histopathologic findings is often critical in diagnosing difficult cases. In this way, careful attention to proper labeling allows one to return to the appropriate area for additional sections if needed.

A diagram or photograph showing the location of sections is very useful in any situation, but particularly for IBD colectomies.

1. Measure: length and diameter of specimen, length and diameter of each structure (ileum, colon, appendix, etc.), staple lines, amount of mesentery.
2. Describe any serosal or mesenteric abnormalities (perforations, adhesions, masses).
3. Open the colon along the anterior free tenia and the small bowel along the anterior aspect of the mesenteric border.
4. Gently remove blood or stool with a rinse of saline.
5. Photograph at low power (in correct anatomic position) and then take close-up photographs of individual areas of interest. Be sure to record where the latter photographs were taken so comparison can be made with the corresponding histologic sections. Use the images to diagram appropriate findings and mode of sectioning.
6. Remove mesentery and search for lymph nodes.
7. Stretch and pin on corkboard and fix in formalin overnight. As fixation may bring out lesions inapparent in the fresh state, one may wish to take more photographs the following day.

Grossing In

1. Identify type of resection specimen: partial or total colectomy, presence of anal canal (proctocolectomy) and/or portion of terminal ileum and appendix.
2. Measurements - describe as above.
3. Describe the following:
   1. Mucosa: type of lesions (e.g.: pseudomembranes, transmural necrosis, diverticula, perforation, incidental polyps, etc.). In IBD, describe areas of abnormal mucosa (aphthoid or broad based ulcers, friable mucosa, fissures, fistulae, inflammatory polyps, dysplasia associated lesions or masses (DALM, the term refers to a mass or irregularity in the mucosa of an IBD bowel that is later recognized on microscopic exam to show dysplasia) and note distance from the proximal or distal resection margins.
   2. Wall: thickening, atrophy, fibrosis, necrosis, pattern of fat distribution (e.g. “creeping fat”, which refers to fat that surrounds an increased proportion of the bowel circumference, suggestive of Crohn’s disease).
   3. Serosa: fibrin, pus, fibrosis, adherence of mesentery.
   4. Diverticula: number (it’s accepted to use descriptors such as “numerous” when there are too many), size, location in reference to tenia, evidence of inflammation, hemorrhage, perforation or fistulae. Note the presence of associated muscular thickening.
   5. Resection margins: Do they appear involved by mucosal pathology?
4. Summary of sections:
   1. As many as necessary to sample abnormal areas
   2. Proximal and distal margins of resection.
   3. Appendix (if included in specimen).
   4. Any enlarged nodes, plus a sampling of others.
5. Specific sectioning In IBD:
   1. All areas suspicious for dysplasia or cancer (raised, polypoid).
   2. Random sections are submitted every 10 cm throughout the length of the specimen.
   3. Resection margins.
   4. Lymph nodes.
6. Process appendix as routine.

All sections should be labeled as to source on an accompanying diagram. Remember to also label photograph for comparison.

Sample Dictation

Colon for diverticulitis:

The specimen is received (fresh, in formalin), in one container labeled with the patient’s name and medical record number and designated “colon”. It consists of a partial colectomy measuring x cm in length and x cm in greatest diameter, containing two staple lines measuring x cm and x cm, respectively. The serosal surface appears smooth and glistening except for a focal area of dullness and hemorrhage located x cm from the staple lines. This area appears indurated with a mesenteric mass measuring _ x _ x _ cm, grossly consistent with a potential abscess. The specimen is inked entirely and opened to reveal numerous diverticula measuring up to x cm. Adjacent to the area of serosal induration, there is a diverticulum with potential perforation, measuring _ x _ x _ cm, and containing a fecalith. Otherwise the mucosa appears tan and velvety, with no other grossly identifiable lesions. Representative sections are submitted as follows:

1A and 1B: staple line #1

1C and 1D: staple line #2

1E and 1F: representative sections of the largest diverticulum and mesenteric mass

1G and 1H: additional representative sections of diverticula

1I representative section of uninvolved mucosa.

Colon for IBD:

Specimen #1 is received in one formalin-filled container, labeled with the patient’s name and medical record number and designated "rectum and colon". The specimen consists of a portion of colon including the sigmoid colon, rectum and anal canal measuring overall 33.0 x 10.0 x 2.5 cm. The proximal end is stapled and measures 1.1 cm. The distal end is open, consists of skin surrounding the anal canal and measures 5.5 cm in greatest diameter. The external surface of the specimen is remarkable for an area of fibrosis with thinned out perirectal tissue measuring 5.5 cm, present 8.5 from the distal margin and 25 cm from the proximal margin. This region is inked black. The remainder of the specimen is inked green. The distal margin is inked blue. The specimen is opened to reveal an attenuated colonic lumen measuring 1.2 cm in greatest diameter. The wall of the bowel appears thickened and measures 0.5 cm in greatest thickness. The specimen is remarkable for an area of mucosal reddish discoloration located in the rectal and anal regions extending to a length of 13.5 cm from the anal region superiorly. The anal region is remarkable for polypoid masses. The mucosa of the remainder of the specimen appears flattened and has a brownish discoloration involving the proximal margin as well. No grossly unremarkable colonic mucosa is identified. No lymph nodes are grossly identified. The pericolonic and perirectal fat is dissected out and submitted in toto as below. No masses, fistulae, polyps, fissures, ulcers or any other lesions are seen. The specimen is photographed. Sections are submitted as follows:

1A: shave of proximal margin.

1B through 1F: radial blue inked margin shaved and entirely submitted.

1G: representative section of skin surrounding anal canal.

1H: representative section of anal polypoid masses.

1I through 1R: area with reddish discoloration entirely submitted.

1S through 1V: representative sections taken at 10 cm intervals from proximal to distal.

Another example: "red, friable and ulcerated mucosa extends from the distal resection margin for a distance of 80 cm. Located 20 cm from this margin is a 3 x 2 cm velvety, red excrescence, and at 40 cm there is an ulcer 2 cm in diameter with a thickened and firm underlying wall".

Review and Signout

Colon for diverticulitis

You're just documenting the need to take this bowel out (transmural inflammation, perforation, ischemia), and whether the margins are involved.

1. Colon, segmental resection:

Colon with diverticulitis (with stricture formation, perforation, etc.) and serositis (to document that it is transmural, i.e. severe).

Viable margins of resection.

X lymph nodes, no tumor seen (0/X).

Colon for ischemia

1. Colon, segmental resection:

Colon with focal transmural ischemic injury, viable margins of resection.

Colon for IBD

Remember to describe the lesions as well as the margins. You should mention if they appear involved in your gross description. It is essential to evaluate for dysplasia and/or carcinoma.

1. Colon, segmental resection:

Inflammatory bowel disease, ___ active. Fill in how active (i.e. neutrophilia) the disease is. You can add things like "with stricture formation" or "with ileo-colonic fistula formation" or the like. Often times, we add a note and expound on the features we see (crypt architecture distortion, cryptitis, crypt abscess formation, transmural involvement?, skip lesions). Dysplasia should always be mentioned (i.e. no dysplasia seen, with low-grade dysplasia, with high-grade dysplasia.

(Hyperplastic, adenomatous) polyp(s). If any.

Proximal and distal resection margins free of involvement.

X lymph nodes, no tumor seen (0/X).

Adenomatous changes should be interpreted with caution. If not surrounded by mucosa with inflammatory changes, and show typical adenomatous features, then it’s reasonable to identify them as adenomatous polyps (i.e. sporadic, and not related to the underlying IBD). On the other hand, dysplasia within areas of inflammatory change needs close examination, since there can be invasive carcinoma arising in these lesions.

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