Clinical, laboratory and ultrasonographic findings differentiating low-grade intestinal T-cell lymphoma from lymphoplasmacytic enteritis in cats

Abstract

Background: Low-grade intestinal T-cell lymphoma (LGITL) is the most common intestinal neoplasm in cats. Differentiating LGITL from lymphoplasmacytic enteritis (LPE) is challenging because clinical signs, laboratory results, diagnostic imaging findings, histology, immunohistochemistry, and clonality features may overlap.

Objectives: To evaluate possible discriminatory clinical, laboratory and ultrasonographic features to differentiate LGITL from LPE.

Animals: Twenty-two cats diagnosed with LGITL and 22 cats with LPE based upon histology, immunohistochemistry, and lymphoid clonality.

Methods: Prospective, cohort study. Cats presented with clinical signs consistent with LGITL or LPE were enrolled prospectively. All data contributing to the diagnostic evaluation was recorded.

Results: A 3-variable model (P < .001) consisting of male sex (P = .01), duration of clinical signs (P = .01), and polyphagia (P = .03) and a 2-variable model (P < .001) including a rounded jejunal lymph node (P < .001) and ultrasonographic abdominal effusion (P = .04) were both helpful to differentiate LGITL from LPE.

Conclusions and clinical importance: Most clinical signs and laboratory results are similar between cats diagnosed with LGITL and LPE. However, male sex, a longer duration of clinical signs and polyphagia might help clinicians distinguish LGITL from LPE. On ultrasonography, a rounded jejunal lymph node, and the presence of (albeit small volume) abdominal effusion tended to be more prevalent in cats with LGITL. However, a definitive diagnosis requires comprehensive histopathologic and phenotypic assessment.

Keywords: alimentary lymphoma; cat; chronic enteropathy; full-thickness intestinal biopsies; inflammatory bowel disease; ultrasonography.

FIGURE 1

Examples of key ultrasonographic key features in cats with low‐grade intestinal T‐cell lymphoma (LGITL) or lymphoplasmacytic enteritis (LPE). The left (A‐D) column shows ultrasonographic images of 4 different cats diagnosed with LGITL. LN: lymph node; m: mucosa; M: muscularis; sm: submucosa. (A) Transverse image of a jejunal segment. Total wall thickness of this segment was 3.3 mm (distance between the white crosses), with a 1.8 mm thick mucosa and a 0.8 mm thick muscularis layer. (B) These jejunal segments have thickening of mucosal and muscularis layers. Note the presence of adjacent mild anechoic peritoneal effusion (*). (C) These 2 jejunal lymph nodes are mildly enlarged with a normal echogenicity. (D) This jejunal lymph node is mildly enlarged, measuring up to 7.9 mm in thickness (white crosses). It is also hypoechoic and has rounded margins. (E) A transverse image of a jejunal segment. The total wall thickness of this segment is 3.2 mm, with a 1.0 mm thick mucosa and a 1.3 mm thick muscularis layer. (F) Sagittal image of a jejunal segment exhibiting muscularis layer thickening. (G) This jejunal lymph node is normal in size, measures up to 4.2 mm in thickness (distance between white crosses), and also has both a normal shape and echogenicity. (H) This jejunal lymph node is normal in size, measuring up to 4.7 mm in thickness, and has a normal echogenicity. The margins of its caudal pole (on the right part of the image) are slightly rounded