KRT20 and acinar cell carcinoma: For this reason, a basic IHC panel that includes CK7, cytokeratin 20 (CK20), synaptophysin and trypsin should be performed for the differential diagnosis of other primary solid pancreatic neoplasms, especially well-differentiated neuroendocrine tumours (NETs), neuroendocrine carcinoma and acinar carcinoma, or of metastases of other neoplasms (Table 1).