Figure 4. Banff Lesion Score t-IFTA (tubulitis) in moderately atrophic tubules. Moderately atrophic tubules are defined as having less than 50% down to 25% of the diameter of the surrounding “unaffected or minimally affected [cortical] tubules in the biopsy”.12 This example shows such unaffected or minimally affected tubules with their diameter marked in black. Their mean diameter in this image would be around 48 μm. The tubule with the diameter marked in grey has a diameter of 27 μm which is more than 50% of 48 μm. Thus, this tubule would still qualify as mildly atrophic and would inform Banff Lesion Score t if this lesion was found in multiple (at least 2) foci. It is heavily infiltrated with mononuclear cells (grey arrows). In contrast, the tubule with the diameter of 20 μm marked in red is moderately atrophic, hence it would inform Banff Lesion score t-IFTA, but not Banff Lesion Score t. PAS, original magnification x400.