Morphological and proliferative assessment of 30 feline Intestinal T-Cell Lymphomas

The current WHO classification of animal lymphoma is derived from the REAL schemes (Valli et al., 2002) and allows to typify 75% of cases with routine histopathology (Pittaluga et al., 1996; Founrel-Fleury et al., 2002) while immunophenotyping is mandatory only for the remaining cases. Intestinal T-cell lymphoma (ITCL) is a category characterized by darkly stained, small-to-medium T-cells (CD3+) (Valli et al., 2002) previously described as medium-to-large cells (French et al., 1996). After morphological observation of 30 feline ITCL, in our experience and according to the human classification (Harris, 1995) cell size can vary from small lymphocytes to large immunoblasts and the cut-off factor is represented by peculiar topography, epitheliotropism and neonagiogenesis. Immunohistochemistry with MIB1 showed huge difference in proliferation between our cases, suggesting either to rearrange the ITCL category, that does not perfectly fit to atypical alimentary feline T-cell lymphomas, or to create a further new subclass for them. These observations and other findings coopted by oncologists could aid in the arrangement of veterinary lymphoma classification, as similar critical points have been solved in human medicine (Pileri et al., 1999; Harris et al., 2000).