Questions & Answers on TIL-assessment
A : There is no minimal size to fibrosis or necrosis. In general, when we refer to fibrosis this is best illustrated by the so-called fibrotic focus which is sometimes seen in breast cancer (Ref.: Van den Eynden GG, et al. Histopathology. 2007 Oct;51(4):440-51). When this is fibrotic focus is infiltrated by tumor cells, then this restriction does not apply. All mononuclear cells in areas of necrosis, irrespective of the size of this necrotic area are excluded.
A : All mononuclear cells (including lymphocytes and plasma cells) should be scored, but polymorphonuclear leukocytes are excluded.
A : This is indeed often found. The spatial importance of stromal TIls adjacent to tumorcells nests versus those stromal TILs that are not adjacent to the tumorcell nests is an active area of investigation right now. Digital pathology tools and/or machine learning algorithms are in full development and these may potentially answer this question one day.