Page 448 - WSAVA2018
P. 448

 25-28 September, 2018 | Singapore
The quality of endoscopically obtained biopsies greatly influenc- es the likelihood for an accurate histopathological diagnosis of a specific mucosal lesion.1,2 In general at least six adequate sam- ples need to be collected from the feline gastric or duodenal mucosa to reliably detect abnormalities.1,2 An adequate biopsy should have a full thickness mucosa and at least three or four intact, if possible contiguous villi.2 Samples containing submu- cosa are preferred. These requirements can be challenging to meet in the feline intestine due to the small intestinal diameter and therefore limited feasibility to direct the forceps tip in to the mucosa at a suitable angle and depth.
After obtaining the specimen, the biopsy forceps are removed from the endoscope and the tissue sample is carefully removed from the jaws. Placing the jaws containing the sample into a container filled with isotonic saline and then “washing-off” the sample by shaking the tip of the forceps helps to avoid damag- ing the edges of the cups Specimens should be submitted in fixative, to the pathology laboratory, as quickly as possible for histopathological examination. Submission of a complete history and macroscopic evaluation report to the pathologist is manda- tory to obtain best results.
Unfortunately, there’s often a big discrepancy between the macroscopic appearance and final histological diagnosis thus emphasising the absolute importance of collecting endoscop- ic biopsies during all endoscopic examinations. Differentiation between lymphoplasmacytic IBD and small-cell lymphoma is notoriously difficult and should be confirmed with immunohisto- chemistry and PARR testing in those clinically suspicious cases.7,8
Large intestinal disease in cats commonly results in large bowel diarrhoea or constipation. It must be remembered, that vomiting is another frequent complaint in cats with large bowel disease. Furthermore, haematochezia can be due to local problems in the large intestine or anorectal disease and must be differentiat- ed from generalised coagulopathies. As mentioned previously, a thorough investigation for systemic diseases is warranted for all these problems including haematology, biochemistry, coagu- lation testing, faecal analysis and diagnostic imaging.
The commonest abnormal large intestinal disease in cats is some form of colitis. This can be limited to the colon or be part of IBD or even small cell lymphoma of the entire intestinal tract. Colonic tumours, especially lymphoma, can look identical to in- flammatory colitis and must be differentiated by histopathology and PARR (+/-immunohistochemistry)7,8, for definitive diagnosis. Other large intestinal tumours in cats include adenocarcinoma and leiomyosarcoma, both being more focal and often invading the lumen with an irregular proliferative appearance. Other rare findings in cats include ileocolic or ileocaecal intussusception (often diagnosed via ultrasound prior to endoscopy) or rectal stricture.
1. Day, M. J, Bilzer, T., Mansell, J., et al. (2008) World Small Animal Veterinary Asso- ciation Gastrointestinal Standardisation Group. Histopathological standards for the diagnosis of gastrointestinal inflammation in endoscopic biopsy samples from the dog and cat: a report from the World Small Animal Veterinary Association Gastro- intestinal Standardisation Group. Journal of Comparative Pathology 138, S1-S43
2. WSAVA International Gastrointestinal Standardization Group: Washabau RJ, Day MJ, Willard MD, et al. (2010) ACVIM Concensus Statement: Endoscopic, Biopsy, and Histopathologic Guidelines for the Evaluation of Gastrointestinal Inflammation in Companion Animals. J Vet Intern Med. 24, 10-26.
3. Neiger, R., Robertson E., Stengal C. (2013) Gastrointestinal endoscopy in the cat: Diagnostics and therapeutics. J Fel Med Surg 15, 993-1005.
4. Stengal C., Robertson E., Neiger R. (2013) Gastrointestinal endoscopy in the cat: Equipment, techniques and normal findings. J Fel Med Surg 15, 977-991.
5. Smith AA, Posner LP, Goldstein RE et al. (2004) Evaluation of the Effects of pre- medication in gastroduodenoscopy in cats. JAVMA 225, 540-544
6. Sabattini, S., Bottero E., Turba M.E., et al. (2016) Differentiating feline inflammatory bowel disease from alimentary lymphoma in duodenal endoscopic biopsies Jour- nal of Small Animal Practice 57, 396-401
7. Kiupel, M., Smedley, R. C., Pfent, C., et al. (2011) Diagnostic algorithm to differen- tiate lymphoma from inflammation in feline small intestinal biopsy samples. Veteri- nary Pathology 48, 212-222
8. Moore, P.F., Rodriguez-Bertos, A., Kass, P.H. (2012) Feline gastrointestinal lym- phoma, mucosal architecture, immunophyenotype, and molecular clonality. Veter- inary Pathology 49, 658-668
9. Washabau RJ, Hasler AH. (1997) Constipation, Obstipation, and Megacolon. In: August JR (ed) Consultations in feline Medicine, 3rd ed. Philadelphia, WB Sauders,
pp 104-112.

   446   447   448   449   450