Figure 1.

Histological evaluation of Crohn's like reaction. HE-stained sections of MSI-H tumours with marked lymphocyte infiltration. (A) Exemplary illustration of Crohn's like lesions (black arrows) with apparent germinal centres surrounding the invasion front of the tumour (× 100 magnification). (B) Peritumoural lymphocytes surrounding the penetration border of the primary tumour like a cap (× 50). Note the pronounced Crohn's like lymphoid reaction. Germinal centres that were not mandatory for the diagnosis of CLR are clearly detectable in both tumour sections.