PT - JOURNAL ARTICLE AU - C J Howlett AU - E J Tweedie AU - D K Driman TI - Use of an elastic stain to show venous invasion in colorectal carcinoma: a simple technique for detection of an important prognostic factor AID - 10.1136/jcp.2009.065615 DP - 2009 Nov 01 TA - Journal of Clinical Pathology PG - 1021--1025 VI - 62 IP - 11 4099 - http://jcp.bmj.com/content/62/11/1021.short 4100 - http://jcp.bmj.com/content/62/11/1021.full SO - J Clin Pathol2009 Nov 01; 62 AB - Background: Venous invasion (VI) is an important prognostic factor in colorectal cancer; it is positively associated with visceral metastases and may affect the decision to treat with adjuvant therapy. Aims: To evaluate whether an elastic tissue (Movat) stain facilitates identification of VI, the number of Movat-stained blocks needed to detect VI, and whether VI identified with a Movat stain is prognostically equivalent to VI identified on H&E-stained slides. Methods: H&E-stained sections from colorectal carcinomas from the year 2000 (n = 92) were examined for VI and compared to Movat-stained slides. Clinical charts were reviewed to compare rates of metastases in VI-positive versus VI-negative patients. Results: With the Movat stain, VI was identified in 44% of cases previously categorised as negative (p<0.001) on review of H&E slides alone. One Movat-stained section was often sufficient to identify VI, with a statistically significant benefit to performing multiple stains if necessary. In H&E sections, two clues helped identify VI: the “unaccompanied artery” sign, where large arteries were seen without an accompanying vein; and the “protruding tongue” sign, where smooth tongues of tumour extended into pericolic/rectal fat. Metastases were present in 61% of cases positive for VI compared to 35% in VI-negative cases (p = 0.03). 45% of cases positive for intramural VI only developed metastases (p = 0.39), while 65% of cases positive for extramural VI only developed metastases (p = 0.03). Conclusions: Pathologists should look for morphological clues of VI in H&E stained sections; when VI is not apparent, an elastic tissue stain on all tumour blocks significantly improves identification of VI. Morphological clues include the “unaccompanied artery” and “protruding tongue” signs.