Russell KJ, Beatty JA, Dhand N, et al. Feline low-grade alimentary lymphoma: how common is it? J Feline Med Surg. 2012; 14: 910-2.
The most common anatomical form of lymphoma in cats is alimentary lymphoma (AL). It is characterized by an infiltration of the gastrointestinal tract and/or associated lymph nodes with neoplastic (cancerous) lymphocytes. There are three subtypes based on mitotic rate and cell type (determined by examination of biopsy samples): low grade (LG-AL), intermediate-grade (IG-AL), and high-grade (HG-AL). Low-grade alimentary lymphoma requires a histological evaluation of biopsies for diagnosis while intermediate- and high-grade alimentary lymphoma can be diagnosed by cytology of intestinal or mesenteric lymph node aspirates. It is usually not possible to differentiate LG-AL from inflammatory bowel disease or benign lymphoid hyperplasia by using cytology alone.
The authors investigated the relative prevalence of AL subtypes diagnosed by both histopathology and cytology among cases in Australia over a 5-year period. The studied identified 53 cases of AL, comprising 30 diagnosed by histology (15 LG-AL, 13, HG-AL, 2 IG-AL) and 23 (IG-AL/HG-AL) diagnosed by cytology. LG-AL accounted for 28% of all diagnosed alimentary lymphoma cases, and 50% of cases diagnosed by histopathology. A palpable abdominal mass, anemia, and a gastrointestinal mural (wall) mass found on abdominal ultrasound (0% of LG-AL cases) were more common in IG-AL/HGAL than in in LG-AL. Gastric/intestinal wall thickening was the most commonly reported abnormality (82%) when a detailed abdominal ultrasound report was available. When intestinal thickening was noted, a loss of normal layering was more common in cats with IG-AL/HG-AL than those with LG-AL. Hypoalbuminemia (low serum albumin levels) was found in 25% of the cats with IG-AL/HG-AL and none of the cats with LG-AL. Of 15 cats tested for FIV and FeLV, 3 were positive for FIV antibody and none were positive for FeLV antigen. [VT]