Immunostaining was done with appropriate positive and negative controls and revealed:
Diffuse positive reaction in the large undifferentiated cells to CK, whereas negative to CD45 & CD20.
Referred block for immunostaining of gastric outlet obstruction endoscopic biopsy diagnosed as undifferentiated large round cell infiltrate (pathology number 3175-2026, on 13 May 2026).
One referred paraffin block coded (3175-2026).
Immunostaining of gastric biopsy: