Ectopic Tumors of the Lung

Ectopic tissues occurring in the lower respiratory tract are an uncommon finding. Even more unusual is the development of neoplasms from such tissues. In the lung, these tumors include a heterogeneous group of lesions with varied histology and clinical behavior. What unifies these neoplasms is the similar morphological appearance to their counterparts in native locations. Close correlation with clinical examination and radiologic imaging to exclude metastatic disease to the lung, a process which is by far more common, is thus always essential before the diagnosis can be confirmed. Documented primary lung tumors of presumed ectopic origin include the family of glomus tumors, thymoma, melanoma, meningothelial proliferations, teratoma, and ependymoma.