Respiratory Tract Cytology

Abstract

The respiratory tract is traditionally divided into upper airway (sinonasal space to larynx) and lower airway (trachea to lungs). In this chapter, the focus will be on the lower airway which accounts for the majority of specimens from the respiratory tract that cytopathologists are expected to review. These specimens have increased in number, partly due to the tremendous advances in thoracic imaging which have allowed radiologists to detect an ever-increasing number of thoracic lesions that need cytological evaluation. Often the differential diagnosis includes non-neoplastic conditions (e.g., infections, iatrogenic) vs truly neoplastic entities. The clinical and radiologic findings are however rarely conclusive for the treating physicians. Thus, histological and/or cytological diagnosis of these lesions are required for selecting the appropriate therapeutic management.