Table 3.

Differentiating neuroendocrine tumors with immunohistochemical markers

Immunohistochemical markers	Paraganglioma	Typical carcinoid	Atypical carcinoid	Small cell neuroendocrine tumor	MTC	FTC
1.Neuro-specific enolase	(+)	(+)	(+)	(+)	(+)	(−)
2.Chromogranin A	(+)	(+)	(+)	(+)	(+)	(+)
3.Synaptophysin	(+)	(+)	(+)	(+)	(+)	(−)
4.Glial fibrillary acidic protein*	(+)	(−)	(−)	(−)	(+)	(−)
5.S-100 protein*	(+)	(−)	(−)	(−)	(−)	(−)
6.Cytokeratin	(−)	(+)	(+)	(+)	(+)	(+)
7.Calcitonin	(−)	(+)	(+)	(+)/(−)	(+)	(+)
8.CEA	(−)	(+)	(+)	(+)	(+)	(+)
9.EMA	(−)	(+)	(+)	(+)	(+)	(+)
10. TTF1	(−)	(−)	(−)	(+)/(−)	(+)	(+)
11. MIB-1	(−)	(−)	(−)	(−)	(−)	(+)

MTC medullary thyroid carcinoma; FTC follicular thyroid carcinoma; CEA carcinoembryonic antigen; EMA epithelial membrane antigen; TTF-1 thyroid transcription factor 1; MIB-1 molecular immunology Borstel number 1

*Positivity only in the sustentacular cells