Unusual Symptoms

Procedure Pathology Report Colon October 7, 2014


Surgical Pathology Report
Service Date: 9/29/14


Final Pathologic Diagnosis


Right colon, hemicolectomy:
1. Adenocarcinoma, 2.6 cm, moderately differentiated, arising in cecal tubular adenoma and invading into muscularis propria, negative margins; see comment.
2. Appendix with fibrous obliteration.
3. Small intestinal tissue with no significant pathologic abnormality.
4. No tumor in fifteen lymph nodes (0/15).


Comment:
Colon and Rectum Tumor Synoptic Comments

- Location of tumor: Cecum.
- Type of tumor: Adenocarcinoma.
     - Are there clinical or pathological criteria present to do microsatellite instability PCR in addition to MMR immunohistochemistry:
No clinical or pathologic criteria to do both MMR immunohistochemistry and MSI PCR. Only MMR immunohistochemistry will be performed on block A3 (see below).
- Tumor size: 2.6 x 1.8 x 1.8 cm.
- Macroscopic tumor perforation: None.
- Grade of tumor: Low grade.
- Treatment effect: N/A.
- Microscopic depth of invasion: Tumor invades muscularis propria.
- Blood/lymphatic vessel invasion: None.
- Perineural invasion: None.
- Margins: Negative.
- Proximal margin: Negative; tumor is 3.3 cm from margin.
     - Distal margin: Negative; tumor is 11.4 cm from margin.
     - Serosa: Negative; tumor is 0.6 cm from serosa/slide A4.
- Lymph node status: Negative; total number of nodes examined: 15.
- Satellite tumor deposits (TD): None.
- Other pathologic findings in bowel: Polyps;
     - Polyps with invasive carcinoma: Tubular adenoma.
- AJCC/UICC stage: pT2NO.

Per request of Dr. [...], immunohistochemical studies were performed to evaluate whether the tumor shows loss of mismatch repair protein expression on block A3. The following immunohistochemical stains were performed and evaluated. Results in the tumor cell nuclei are:

MLH1 expression: Absent.
MSH2 expression: Present.
MSH6 expression: Present.
PMS2 expression: Absent.

Absence of staining indicates that the tumor shows loss of one of the mismatch repair proteins. However, the immunohistochemical stain does not distinguish between loss due to promoter hypermethylation and loss because the patient is a carrier of a mismatch repair gene mutation associated with Lynch syndrome. This result should be correlated with the microsatellite instability (MSI) test. Referral for clinical genetics evaluation and counseling should be considered to help distinguish between these possibilities for the patients and their family members.



Immunohistochemistry for mismatch repair proteins (MMR) and polymerase chain reaction (PCR) for microsatellite instability (MSI) are offered at UCSF to evaluate whether a tumor shows mismatch repair deficiency. The results of the MSI test are issued directly from the Molecular Pathology Laboratory.



The immunoperoxidase stain(s) reported above were developed and their performance characteristics determined by the UCSF Medical Center Department of Pathology. They have not been cleared or approved by the U.S. Food and Drug Administration. The FDA has determined that such clearance or approval is not necessary. These tests are used for clinical purposes. They should not be regarded as investigational or for research. This laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 ('CLIA') as qualified to perform high-complexity clinical testing.