Special tumours of the head and neck

Most lesions encountered by surgical pathologists in the head and neck region are benign and malignant proliferations of the squamous mucosa. However, there are some uncommon tumours arising from specialized epithelium and stroma of this region. These lesions include Schneiderian papilloma, low-grade sinonasal adenocarcinoma, intestinal-type sinonasal adenocarcinoma, sinonasal undifferentiated carcinoma, olfactory neuroblastoma, nasopharyngeal angiofibroma, sinonasal haemangiopericytoma, neuroendocrine adenoma of the middle ear, and endolymphatic sac tumour. Given the rarity of these tumours, a crucial key for their correct diagnosis is a keen awareness of their morphologic and immunohistochemical features. In this review, we attempt to present some salient or recent clinicopathologic and prognostic findings of these fascinating neoplasms.