Testis : Carcinoid - Synaptophysin

Comments:
As in other locations, well-differentiated neuroendocrine tumors (carcinoids) of the testis can be positive for synaptophysin (shown here), chromogranin, neuron-specific enolase, VIP, neurofilament protein, gastrin, as well as cytokeratin. They are negative for OCT3/4, CD30, c-kit, TTF-1, and CDX-2.