Cytology is increasingly being used in the evaluation of lung lesions. There are several potential pitfalls and mimics encountered in the evaluation of respiratory cytology specimens, making interpretation of respiratory cytology challenging. Familiarity with the mimics and the pitfalls is essential in avoiding a misdiagnosis because a false positive or false negative diagnosis may have significant management implications. This article focuses on the main classification of primary lung carcinoma - small cell carcinoma, adenocarcinoma and squamous cell carcinoma - with potential mimics discussed under each tumor category. We have attempted to separate pitfalls from common potential mimics and have suggested general rules when such pitfalls are encountered.
Keywords: Pitfalls; adenocarcinoma; clinical history; lung cancer; mimics; non-small cell carcinoma; pulmonary carcinoma; respiratory cytology; squamous cell carcinoma.