PD-L1/PD-1 check-point in gastric carcinoma with lymphoid stroma case report with immunochemical study

Gastric carcinoma with lymphoid stroma is an unusual type of gastric tumor associated with a better prognosis than typical gastric carcinomas. The hallmark of this cancer is a prominent lymphoid infiltration of the stroma that represents an intense host lymphocytic response. The programmed death 1-programmed death-ligand 1 (PD-1/PD-L1) axis has recently emerged as a master immune checkpoint that controls antitumor immune responses against many neoplasms.

We report the case of a male patient with gastric carcinoma with lymphoid stroma with a large mass infiltrating the gastric wall without nodal metastasis. He is alive without disease 10 months after surgery. We focused the study on factors that potentially modulate the prognosis. In this setting we demonstrate, for the first time in this type of tumor, by immunohistochemistry a strong PD-L1 expression in neoplastic cell and the presence of PD-1 positive infiltrating lymphocytes.

The applied approach may contribute to the knowledge about host reaction in such tumor and it may also be used for tumor precise identification on the endoscopic biopsy time before excision surgery.