Peripheral small-cell carcinoma of the lung resembling carcinoid tumor. a clinical and pathologic study of 14 cases
Mark, E.J.; Ramirez, J.F.
Archives of Pathology and Laboratory Medicine 109(3): 263-269
1985
ISSN/ISBN: 0003-9985 PMID: 2983637 Document Number: 248190
We studied 14 small-cell, epithelial tumors of the lung with histologic features intermediate between typical carcinoid tumor and undifferentiated small-cell carcinoma. All of the tumors arose in the periphery of the lung beyond a segmental bronchus and were excised. Histologically, three of the tumors were low grade and 11 were high grade. The low-grade tumors had an organoid pattern comprising more than half of the area examined histologically, less than five mitoses per 10 high-power fields, individual cell necrosis, and nuclear pleomorphism of less than half of the cells. The high-grade tumors had the opposite characteristics. Distinction of these peripheral tumors from typical carcinoid tumors and from undifferentiated small-cell carcinomas is established after excision and cannot be made reliably on the findings of a transbronchial or needle biopsy. Prognosis was worse than that for typical carcinoid tumors but better than that for undifferentiated small-cell carcinomas.