Cytomorphology of the variants of small-cell carcinoma of the lung.

Cytologic classification of subtypes of small-cell carcinoma of the lung (SCCL) was retrospectively performed on respiratory material of 90 cases of lung carcinoma cytologically diagnosed as SCCL. Additionally, the cytologic material was reexamined for the presence of variants of SCCL in 68 cases of lung carcinoma whose types had not been conclusively defined by cytology. The type of lung cytology specimens reviewed were sputa, bronchial washings and brushings and fine needle aspirations. The study included review of pretreatment tumor histology, when present, and examination of the ultrastructure of the tumor in selected cases whose type had not been well defined by histology. Subtype recognition depended on the adequacy of the specimens rather than on the type of cytologic material examined. The cytologic subtyping was generally in agreement with the histologic subtyping of the tumor, except for cases in which SCCL was combined with other types of lung carcinoma, where certain discrepancies were noted.