Immunistaining done with appropriate positive and negative controls and revealed:
MLH1: Intact, nuclear expression in >90% of tumor cells.
PMS2: Intact, nuclear expression in >90% of tumor cells.
MSH2: Intact, nuclear expression in >90% of tumor cells.
MSH6: Intact, nuclear expression in >90% of tumor cells.
Referred block for immunostaining of rectosigmoid mass diagnosed as Adenocarcinoma grade 2 (pathology number 3700-2026 on 9 June 2026).
One referred paraffin block.
Immunohistochemistry of rectosigmoid mass: