Equine Intestinal Lymphoma: Clinical-Pathological Features, Immunophenotype, and Survival

Abstract

Lymphoma is the most common intestinal neoplasm in horses, but its clinical-pathological features are poorly characterized. Primary intestinal lymphoma was diagnosed in 20 horses on biopsy samples and further confirmed by postmortem examination in 16 cases. Lymphoma was found in the small intestine in 12 of 20 (60%), in the colon in 5 of 20 (25%), and in both small and large intestines in 3 of 20 (15%) cases. Gross findings included thickening of the intestinal wall (45%), mural nodules or masses (30%), and both thickening and nodules (10%). Cases were classified according to the human World Health Organization classification as enteropathy-associated T-cell lymphoma (EATL) type 1 (40%), EATL type 2 (45%), and T-cell-rich large B-cell lymphoma (TCRLBCL) (15%). With respect to histologic grade, 70% of cases were grade 1 and 30% were grade 2. Of EATLs, the infiltrate was mucosal only (12%), mucosal and submucosal (53%), or transmural (35%). EATL1 was submucosal to transmural (2/8 and 6/8), EATL2 was mucosal to submucosal (3/9 and 6/9), and TCRLBCL was always transmural. Epitheliotropism was present in most EATLs and characterized by single-cell infiltrates within the epithelium in EATL1 and intraepithelial clusters or plaques in EATL2. Median survival was 25 days for EATL1, 90 days for EATL2, and 187.5 days for TCRLBCL; differences were not statistically significant. Of the EATLs, grade 1 had a median survival of 60 days and grade 2 had a median survival of 25 days; differences were not statistically significant.

Equine Genital Squamous Cell Carcinoma Associated with EcPV2 Infection: RANKL Pathway Correlated to Inflammation and Wnt Signaling Activation

“…The immunolabeling was revealed with 3-amino-9-ethilcarbazole (Abcam), and Mayer's hematoxylin was applied as a counterstain. Ki67 index was evaluated on 1000 cells using ImageJ cell counter and expressed as a percentage, as previously reported [28].…”

Health problems in geriatric horses

“…Malignant tumors most frequently found in horses include melanoma, mostly affecting grey horses, squamous cell carcinoma, most commonly located in the regions of non-pigmented skin and locations less covered with hair coat, especially the eyes, the region of the muzzle, anus and genitalia (54). The third most regularly diagnosed malignant tumor in horses is lymphoma (6). Lymphomas are generally uncommon in horses, but are considered the most common neoplastic disease of the hemolymphatic system (60).…”

Primary bilateral corneal T cell lymphoma in a horse

“…Median survival time reported for horses undergoing chemotherapy for various classifications of lymphoma is approximately 8 months (Luethy et al., 2019). Median survival time reported for intestinal lymphoma is approximately 60 days (Bacci et al., 2020). Although diffuse systemic disease is more common, there are a few reports of solitary lesions, which rarely affect the globe (Tanimoto et al., 1994; Trope et al., 2014).…”