Neuroendocrine carcinomas of the lung: clinical, radiologic, and pathologic correlation

Neuroendocrine carcinomas of the lung are characterized by differentiation toward Kulchitsky cells and are classified as Kulchitsky-cell carcinoma (KCC) I (classic carcinoid), KCC II (atypical carcinoid), and KCC III (small-cell carcinoma). The clinical, computed tomographic (CT), and pathologic findings in 31 patients with KCC were reviewed. KCC I lesions generally occurred in younger (56 years +/- 18) nonsmoking women, were small (1.8 cm +/- 0.7 in diameter on CT scans), and were associated with lymphadenopathy in one of ten patients. KCC II tumors were found predominantly in older (66 years +/- 12) smoking men and were larger (3.9 cm +/- 1.3 in diameter, P less than .001); four of ten patients had CT evidence of lymphadenopathy. KCC III tumors occurred in older (66 years +/- 8) smoking men and were large (4.2 cm +/- 1.0); 11 of 11 patients had massive lymphadenopathy. Clinical, radiologic, or pathologic overlap was noted in three patients. Sputum cytologic and fine-needle and bronchoscopic biopsy findings were often nondiagnostic or misleading, particularly for KCC II lesions. CT of the chest provides additional discriminating information in the preoperative diagnosis of neuroendocrine lung carcinomas.