Sections show fragments of extensively ulcerated gastric mucosa infiltrated by a malignant tunor arranged in diffuse sheets of epithelioid cells with focal multinucleated tumor giant cells. Tumor cells exhibit hyperchromatic pleomorphic nuclei, prominent nucleoli, abundant esinophilic cytoplasm and brisk mitotic activity. Extensive areas of tumor necrosis are observed.
Immunohistochemical study performed on the referred block shows diffuse strong positivity for CK and chromogranin. Synaptophysin shows nonspecific staining. Ki-67 labeling index is about 60%. The tumor cells are negative for CD20, CD3, and CD68.
In conjunction with the morphology, the immunophenotypic findings support the diagnosis of neuroendocrine carcinoma, large cell type (Grade 3).
Referred paraffin block for immunostaining of endoscopic biopsy of large fungating gastric mass with superficial ulceration and necrosis.
One referred paraffin block.
Referred block, immunostaining of endoscopic biopsy from gastric mass: