The clinical management of lung neoplasia now involves considerations of several diagnostic categories that were not in common use only a few years ago. In particular, there is now an increased recognition of neuroendocrine differentiation in lung cancer, including acknowledgment of large-cell neuroendocrine cancer as a distinct class of lung cancer. In addition, there is growing awareness of various form of early neoplasia in the lung, particularlyin situsquamous cell proliferations and atypical adenomatous proliferations. With an emphasis on implications for clinical management, this review will discuss the biology of these important categories of lung neoplasia and compare them to other commonly recognized forms of lung tumors.
