Hamartomas, papillomas and adenocarcinomas of the sinonasal tract and nasopharynx

Lesions of the sinonasal tract are uncommon, with most of the specimens seen by surgical pathologists consisting primarily of fragments of inflamed sinonasal mucosa or inflammatory polyps from patients with chronic rhinosinusitis, and the occasional squamous cell carcinoma. Other lesions such as hamartomas, various types of Schneiderian papillomas and adenocarcinomas are seen only rarely by most histopathologists; therefore a biopsy or surgical resection specimen from a patient with one of these processes may represent a diagnostic challenge. The aim of this review is to present the pathological features of a group of infrequent epithelial surface and glandular lesions of the sinonasal tract which includes respiratory epithelial adenomatoid hamartoma, glandular (seromucinous) hamartoma, exophytic papilloma, inverted papilloma, cylindrical cell (oncocytic) papilloma, low-grade sinonasal adenocarcinoma and intestinal-type sinonasal adenocarcinoma.