Pulmonary Papillary Adenoma: Report of Two Cases.

Pulmonary papillary adenoma is a rare tumor. Two cases without any clinical symptoms were enrolled in our hospital. Both cases were incidentally detected in pulmonary area by imaging. Pathological examination revealed well-circumscribed nodules consisting of papillary growth of cuboidal to low columnar epithelial cells lining the surface of the fibrovascular stroma. Immunohistochemistry (IHC) staining showed that the lining cells were diffusely positive for TTF-1, CK, p63, CK7, and Napsin A. The Ki-67 proliferation index was approximately 2%. The morphological features and the IHC profile of the tumor were in agreement with that of pulmonary papillary adenoma. Both patients are doing well without recurrence or metastasis of the tumor.