Immunohistochemical identification of neuron-specific enolase, synaptophysin, chromogranin and endocrine granule constituent in neuroendocrine tumours.

Immunohistochemical identification of neuroendocrine tumour markers in paraffin embedded material from 22 tumours (5 small cell carcinomas of the lung (SCCL), 12 carcinoids, 2 medullary thyroid carcinomas, 2 pheochromocytomas and one paraganglioma) with electron microscopically verified dense-core granules revealed neuron-specific enolase in all but one tumour, synaptophsin in 15/22 (2 SCCL and 6 carcinoids negative), chromogranin in 16/22 (all SCCL and one carcinoid negative), and endocrine granule constituent in 18/22 (4 SCCL negative). The Grimelius silver methods stained 13/22 (all cases of SCCL and 4 carcinoids negative).