neoplasms of the lungs showing neuroendocrine differentiation are classified histologically into the following groups : ( 1 ) carcinoid , ( 2 ) atypical carcinoid ( well-differentiated neuroendocrine carcinoma and malignant carcinoid , ( 3 ) small cell neuroendocrine carcinoma ( small cell undifferentiated carcinoma and oat cell carcinoma ) , and ( 4 ) large cell neuroendocrine carcinoma ( atypical endocrine tumor of the lung and intermediate neuroendocrine carcinoma ) .
C0149925
small cell
C0024109
lung