Page 741 - Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition

CHAPTER 33 Hematopoietic Tumors 719

TABLE 33.10 Characteristics of the Three Most Common Forms of Alimentary/Gastrointestinal Lymphoma in Cats
Low-Grade Alimentary Lymphoma Intermediate-/High-Grade Alimentary
VetBooks.ir Characteristic (LGAL) Lymphoma (I/HGAL) Large Granular Lymphoma (LGL)

≈10% of cases
50%–80% of cases
≈20% of cases
Incidence
Clinical presenta- Nonspecific gastrointestinal signs Nonspecific gastrointestinal signs; vomiting Nonspecific gastrointestinal signs;
tion (anorexia, weight loss, diarrhea, inap- common if gastric; hematochezia more vomiting more common
petence) common if large bowel
Clinical course Indolent clinical progression Acute clinical progression Acute clinical progression
Abdominal palpa- Generally normal, modest intestinal thick- More common to palpate gastric/ intestinal More common to palpate gastric/intes-
tion ening and abdominal lymphadenopathy mass, mesenteric lymphadenopathy, tinal mass, mesenteric lymphade-
possible organomegaly nopathy
Abdominal ultra- Often unremarkable; diffuse intestinal More commonly thickened transmural More commonly thickened transmural
sound findings wall thickening if present is limited to intestinal wall; loss of normal intestinal intestinal wall; loss of normal intes-
muscularis propria /submucosa; normal wall layering; mass effect more likely; tinal wall layering; mass effect more
intestinal wall layering; mild lymphade- mesenteric lymphadenopathy more likely likely; mesenteric lymphadenopathy
nopathy/organomegaly possible more likely; effusion uncommon but
more likely
Topography a

5 1
24* 7
4
18
43

1 8
9
16 2 7

General Cytology generally not helpful; biopsy (full Cytology (mass/lymph node) often diag- Cytology (mass/lymph node) often
diagnostics thickness preferred, but endoscopic nostic; biopsy with histopathology, immu- diagnostic; biopsy with histopathol-
helpful) with histopathology, immuno- nophenotype, and clonality analysis less ogy, immunophenotype, and clonality
phenotype, and clonality analysis often commonly required. analysis less commonly required.
helpful to differentiate from LPE
Cell size >80% small, <20% large >90% intermediate/large Intermediate/large
+
+
Immunopheno- >80% T-cell (CD3 +) ≈100% B-cell (CD79a ) Cytotoxic T-cell (CD3 /CD8 /CD79a ), or
–
+
+
type NK cell (CD3 /CD79a ); often CD103
–
–
and granzyme B +
Clonality >90% clonal or oligoclonal >70% clonal or oligoclonal >90% clonal or oligoclonal
WHO EATCL 90% type II (mucosal) 90% type I (transmural) ≥90% type I (transmural)
classification 10% type I (transmural) 10% type II (mucosal)
Epitheliotropism Common Rare Common
Recommended Chlorambucil/prednisolone CHOP- or COP-based chemotherapy; CHOP- or COP-based chemotherapy;
treatment surgery considered if large discreet surgery considered if large discreet
lesion prechemo; surgery performed if lesion prechemo; surgery performed
obstruction/perforation if obstruction/perforation
Chemotherapy >80% response; median survival 1.5–3 ≈50%–60% response (30% CR); median ≈30% response; median survival 45–90
response and years survival 3–10 months; more durable if days; occasionally more durable
outcome CR

a Numbers indicate number of cases having lymphoma at that location. Areas in red indicate most commonly affected regions of the intestine.
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.