Concurrent mucosal and transmural feline intestinal T-cell lymphomas show differing T-cell clonality

The clonality of 14 feline intestinal small and large T-cell lymphomas were examined, which consisted of concurrent mucosal and transmural lymphomas, respectively. Histologically, the small cell lymphomas were localized to the mucosal region and were observed adjacent to large T-cell lymphoma lesions. The large T-cell lymphomas were spread throughout the submucosal region, forming transmural lesions. Both cell types were immunohistochemically stained using anti-cluster of differentiation 3 antibody. For clonality analysis, genomic DNA was extracted from formalin-fixed, paraffin-embedded sections of the mucosal and transmural lesions, separately. Clonality analysis was performed using primer sets targeting T cell receptor beta, T cell receptor delta, and T cell receptor gamma loci. In 12/14 cats, the results of the clonality analysis for T-cells differed between the mucosal and transmural lesions. Despite the fact that the cellular morphologies differed between lesion types, the T-cell clonality was consistent in 1/14 cats, suggesting a common clonal origin. In the remaining case, the clonal relationship between the 2 lesions could not be determined. These results indicate that concurrent lymphomas with small and large T-cells in their mucosal and transmural lesions, respectively, develop via separate pathogenic mechanisms.