Fig. 5

Comparison of histological and immunohistochemical features of feline low-grade alimentary lymphoma (LGAL) and human indolent digestive T-cell lymphoproliferative disease (LPD). Top Panel: Human indolent CD4⁺ T-cell lymphoproliferative disease of the gastrointestinal tract. Biopsies of the antrum (a, b, c) and duodenum (d, e, f) show important CD3⁺ (b and e) and CD4⁺ (c and f) lymphoid infiltrate into the lamina propria (asterisk), mostly composed by small lymphocytes. Epitheliotropism is mostly absent, with however focal exceptions such as small CD4+ T-cells localized here in the duodenal epithelium (arrow). Bottom Panel: Feline T-cell low-grade alimentary lymphoma. Biopsies of the jejunum show epitheliotropic lymphocytic infiltrate involving the lamina propria (g), exhibiting a CD3⁺ phenotype (h)