Background: It is very difficult to make diagnosis on the HE section to small cell lung carcinoma by bronchoscopic and easy to make misdiagnosis, we can avoid this by using immunohistochemical staining to diagnose differentially among the small cell carcinoma, poorly differentiated squamous cell carcinoma, atypical form carcinoid and lymphoma.
Methods: 64 cases of lung biopsy by bronchoscopic were consistency with small cell carcinoma and stained by immunochemistry for Ki67, CD56, TTF-1, CgA, Syn, P63, CK5/6, LCA, 34betaE12.
Results: For the 64 cases, we diagnosed 61 cases to the small cell carcinoma, 1 case to the poorly differentiated squamous cell carcinoma and 2 cases to the atypical carcinoid after IHC stain.
Conclusions: It is the different therapy among the small cell carcinoma, poorly differentiated squamous cell carcinoma, atypical form carcinoid and lymphoma, so we can identify the diagnosis and differential diagnosis with IHC thoroughly, accordingly decrease incidence of misdiagnosis.