Insulinoma after sleeve gastrectomy: A case report

Figure 2 Histology and immunohistochemistry of the tumor. A: Hematoxylin and eosin photomicrograph (40 ×) showing neoplastic cells presenting uniformly round nuclei with granular chromatin (salt and pepper image), typical of neuroendocrine cells with extensive eosinophilic cytoplasm; B and C: Photomicrographs of immunohistochemical staining for chromogranin (B) and synaptophysin (C) (10 ×). Neoplastic cells show strong immunopositivity for both markers in the cytoplasm, which corroborates the neuroendocrine lineage of the neoplasia; D: Immunohistochemical staining for Ki67 (cell proliferation index). Strong nuclear immunopositivity is seen in approximately 4% of neoplastic cells. The tumor was classified as grade 2, according to the 2019 WHO classification.