Oxyphilic proliferations of the respiratory tract and paranasal sinuses.

: Neoplasms of the upper respiratory comprised primarily of eosinophilic cells are, in general, rare, and they include a diverse group of lesions. Low-grade oncocytic neuroendocrine neoplasms (so-called oncocytic carcinoids) can be encountered in several locations throughout the respiratory tract. The oncocytoma and related entities, lesions that presumably arise from minor gland tissue, can likewise be seen from the nasal cavity to the lung; differences in clinical significance may relate to the location of such lesions, and are discussed herein. Granular cell tumor is another entity that can involve both the upper respiratory tract and lungs, and specific features of this lesion in different anatomic sites are highlighted. The oncocytic variant of Schneiderian papilloma is an important nasal lesion to recognize, because of important therapeutic and prognostic implications of that diagnosis. Finally, unique oncocytic variants of glomus tumor and pulmonary alveolar adenoma are discussed, as well as eosinophilic varieties of pulmonary carcinomas and mesotheliomas.