[756] Use of Elastic Stain in Identification of Venous Invasion in Polyps with Early Invasive Adenocarcinoma (pT1)

Anshu Trivedi, Saverio Ligato. Hartford Hospital, Hartford, CT

Background: Venous invasion (VI) has been reported to be one of the significant predictors for distant metastases in colorectal carcinomas. Unfortunately the assessment of VI on routine hematoxylin eosin (H&E) stained slides is prone to subjectivity. To our knowledge no previous study has looked for VI by elastic stain on polyps with early invasive adenocarcinomas. The aim of our study was to evaluate VI in these lesions using elastic stain and correlate its presence with distant metastases and the clinical outcome.
Design: 15 cases of early invasive carcinoma (pT1) on polypectomy specimens were selected and reviewed by two pathologists for venous invasion. Based on previously described histological features suspicious for VI on H&E sections, such as protruding tongue sign (round-oval smooth-bordered protrusion of tumor into pericolic fat with visible adjacent artery) and unaccompanied artery sign (thick walled artery is visible adjacent to an oval shaped focus of tumor with no normal vein) (J Clin Pathol 2009; 62: 1021-1025), a representative tissue block was selected for Verhoff's Elastic stain. The follow up data for metastatic disease was obtained from medical records.
Results: H&E stain identified VI only in 3 cases (3/15=20%) while elastic stain identified VI in 7/15 cases(47 %). The median follow-up was 3 years. During this period 2/15 cases developed distant metastases. One of these two cases negative on H&E stain, showed VI on elastic stain. The other case did not show VI either on elastic or H&E stain.

VI on H&E and Elastic stain (n=15)
 Positive VINegative VI
H&E stain312
Elastic stain78

Conclusions: 1. Routine use of elastic stain significantly enhances the detection of VI in polyps with early invasive adenocarcinoma (from 20% to 47%).2. The presence of distant metastasis in one of our cases with VI identified only on elastic stain suggests that consideration should be given to the use of elastic stain in cases demonstrating the protruding tongue sign or an unaccompanied artery sign.3. However due to the limited number of cases in our series, we cannot establish if the presence of VI in these malignant polyps has a negative impact on outcome. 4. Consequently additional study with a large number of patients should be done to identify the significance of VI as a risk factor for distant metastases.
Category: Gastrointestinal

Tuesday, March 20, 2012 1:00 PM

Poster Session IV # 75, Tuesday Afternoon


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