Endobronchial masses encountered on fine-needle aspiration biopsy: a focus on unusual entities

Fine-needle aspiration biopsy (FNAB) is a useful technique in the evaluation of central lung tumors which is commonly encountered in clinical cytology practice. Some of these tumors may show endobronchial, polypoid growth which is readily apparent to the endoscopist. Pulmonary salivary gland-type tumors and carcinoid tumors are overall uncommon in the lung, but these tumors tend to occur centrally and show endobronchial involvement. The prognosis of these tumors is generally better than that of small cell or non-small cell carcinomas of the lung and more conservative surgical resection is often indicated. The identification of salient cytological features and a high index of suspicion when considering the differential diagnosis of a central lung tumor is essential to accurate diagnosis. This review focuses on cytological clues as well as ancillary techniques that may be useful to the practicing cytopathologist.