Cytopathologic diagnosis of pulmonary neoplasms in sputum and bronchoscopic specimens

Cytopathologic techniques have been used for the detection and diagnosis of pulmonary neoplasms for many years. Cytopathologic examination of sputum is the most effective method for the detection of early squamous cell carcinoma, but it is not effective for diagnosing peripheral neoplasms, such as adenocarcinomas, in their early stages. Advanced neoplasms of any type, however, can be diagnosed in sputum. The cytopathologic examination of bronchoscopically obtained specimens is a valuable adjunct to biopsies in visible lesions. In addition, it may provide the only microscopic diagnosis in certain peripheral tumors or help in the localization of radiologically occult carcinomas detected by sputum cytology. Although cytopathologic diagnosis of cancer is highly accurate, certain benign conditions can mimic cancer and care must be taken in their interpretation. The type of neoplasm can be accurately diagnosed in well-differentiated carcinomas and small cell carcinomas but less accurately in poorly differentiated and large cell carcinomas. Utilization of proper collection and preparation techniques is crucial for optimal cytopathologic diagnosis.