TABLE 33.10.
Characteristics of the Three Most Common Forms of Alimentary/Gastrointestinal Lymphoma in Cats
| Characteristic | Low-Grade Alimentary Lymphoma (LGAL) | Intermediate-/High-Grade Alimentary Lymphoma (I/HGAL) | Large Granular Lymphoma (LGL) |
|---|---|---|---|
| Incidence | 50%–80% of cases | ≈20% of cases | ≈10% of cases |
| Clinical presentation | Nonspecific gastrointestinal signs (anorexia, weight loss, diarrhea, inappetence) | Nonspecific gastrointestinal signs; vomiting common if gastric; hematochezia more common if large bowel | Nonspecific gastrointestinal signs; vomiting more common |
| Clinical course | Indolent clinical progression | Acute clinical progression | Acute clinical progression |
| Abdominal palpation | Generally normal, modest intestinal thickening and abdominal lymphadenopathy possible | More common to palpate gastric/intestinal mass, mesenteric lymphadenopathy, organomegaly | More common to palpate gastric/intestinal mass, mesenteric lymphadenopathy |
| Abdominal ultrasound findings | Often unremarkable; diffuse intestinal wall thickening if present is limited to muscularis propria /submucosa; normal intestinal wall layering; mild lymphadenopathy/organomegaly possible | More commonly thickened transmural intestinal wall; loss of normal intestinal wall layering; mass effect more likely; mesenteric lymphadenopathy more likely | More commonly thickened transmural intestinal wall; loss of normal intestinal wall layering; mass effect more likely; mesenteric lymphadenopathy more likely; effusion uncommon but more likely |
| Topographya |  |
 |
 |
| General diagnostics | Cytology generally not helpful; biopsy (full thickness preferred, but endoscopic helpful) with histopathology, immunophenotype, and clonality analysis often helpful to differentiate from LPE | Cytology (mass/lymph node) often diagnostic; biopsy with histopathology, immunophenotype, and clonality analysis less commonly required. | Cytology (mass/lymph node) often diagnostic; biopsy with histopathology, immunophenotype, and clonality analysis less commonly required. |
| Cell size | >80% small, <20% large | >90% intermediate/large | Intermediate/large |
| Immunophenotype | >80% T-cell (CD3+) | ≈100% B-cell (CD79a+) | Cytotoxic T-cell (CD3+/CD8+/CD79a–), or NK cell (CD3–/CD79a–); often CD103+ and granzyme B+ |
| Clonality | >90% clonal or oligoclonal | >70% clonal or oligoclonal | >90% clonal or oligoclonal |
| WHO EATCL classification | 90% type II (mucosal) 10% type I (transmural) |
90% type I (transmural) 10% type II (mucosal) |
≥90% type I (transmural) |
| Epitheliotropism | Common | Rare | Common |
| Recommended treatment | Chlorambucil/prednisolone | CHOP- or COP-based chemotherapy; surgery considered if large discreet lesion prechemo; surgery performed if obstruction/perforation | CHOP- or COP-based chemotherapy; surgery considered if large discreet lesion prechemo; surgery performed if obstruction/perforation |
| Chemotherapy response and outcome | >80% response; median survival 1.5–3 years | ≈50%–60% response (30% CR); median survival 3–10 months; more durable if CR | ≈30% response; median survival 45–90 days; occasionally more durable |
CR, Complete response; LPE, lymphocytic-plasmacytic enteritis; WHO EATCL, World Health Organization enteropathy-associated T-cell lymphoma.
Topography diagrams used with permission from: Moore PF, Rodriguez-Bertos A, Kass PH. Feline gastrointestinal lymphoma: mucosal architecture, immunophenotype, and molecular clonality. Vet Pathol. 2012;49:658-668.
a
Numbers indicate number of cases having lymphoma at that location. Areas in red indicate most commonly affected regions of the intestine.