Pathology of the Head and Neck

Nasopharynx and Waldeyer’s Ring Chapter 6 1756.2.3.1 Salivary Gland Anlage TumourSalivary gland anlage tumours are rare tumours of neonatesthat arise from minor salivary glands of the nasopharynxand are also known as congenital pleomorphicadenoma [13, 38, 73]. The firm, polypoid, pedunculatedmidline masses can reach up to 3 cm in size and causerespiratory distress and feeding problems. Salivarygland anlage tumours are multinodular and usuallysolid tumours. Histologically, they are characterised byan epithelial proliferation imitating embryonic salivaryglands (Fig. 6.2). The epithelial proliferation can be extensivewith solid squamous areas with focal keratinisation,keratinised nests, cyst and pearls. Calcificationwithin the cysts occurs. Salivary gland anlage tumoursmay contain branching ductal and glandular structures,occasionally with complex intraluminal papillations.The surrounding stroma may be loose and myxoid withnumerous inflammatory cells, but may also show somefibrosis. Other salivary gland anlage tumours consistpredominantly of densely packed sheet and nodulesof small fusiform spindle cells with occasional regularmitoses. Rare keratinised duct and cystic structures areseen in these areas. Haemorrhage and focal necrosis canbe seen [125]. Immunohistochemically, all cells stainpositive for salivary gland amylase. The spindle cells areimmunoreactive with antibodies to vimentin, cytokeratins,EMA and smooth muscle actin, but are negative forS-100 and GFAP. The epithelial structures stain for cytokeratinand EMA. The exact classification of the salivarygland anlage tumour as a hamartoma or true (benign)neoplasm has not yet been resolved. Dehner andcolleagues favour a hamartomatous origin, although thepresent name indicates a tumourous growth [38].6.2.3.2 Hairy PolypHairy polyps (or dermoids) are found in the naso- andoropharynx of neonates or young infants. About 60% ofthe roughly 140 reported cases arose as single, pedunculatedor sessile, 0.5 to 6 cm polyps in the lateral vaultof the nasopharynx near the Eustachian tube orificeand very rarely within the Eustachian tube and middleear [17, 78, 109]. The remaining cases occurred in thetonsillar region (for tonsillar and bilateral location seeSect. 6.3.2). Hairy polyps cause respiratory distress orfeeding problems. Simultaneous congenital abnormalitiessuch as cleft palate are more common than ipsilateralbranchial sinus, congenital atresia of the carotidartery, osteopetrosis and malformations of the auricle[36, 68]. Treatment is simple surgical resection. A hairypolyp is covered by keratinised or glycogenated squamousepithelium containing hair with sebaceous glandsand sweat glands. The mesenchymal core consists ofmature fibroadipose tissue and blood vessels with occasionalsmooth muscle and striated muscle fibres. Thestalk may contain foci or plates of hyaline cartilage [27].Hairy polyps fulfil the definition of a choristoma, althoughthe literature refers to hairy polyps mistakenlyoften as “teratoma”.6.2.3.3 CongenitalNasopharyngeal TeratomaICD-O:9080/1Congenital teratomas are most common in the saccrococcygealregion; less than one-third of all teratomasarise in the head and neck region. The nasopharynx isan exceptionally rare location [84, 167, 187]. Teratomasare ill-formed, lobular solid and cystic tumour massestypically diagnosed in the neonatal period with airwayobstruction. Mature teratomas are completely benignand consist of mature tissues of ecto-, meso- and endodermalderivation in a more or less organised fashion.Optimal treatment is complete excision. Immatureteratomas contain tissues of varying degrees of differentiationand maturation. Immature teratomas in infantshave an excellent prognosis, quite in contrast to adultpatients with immature teratomas.6.2.4 Benign Tumoursand Tumour-Like Lesions6.2.4.1 Nasopharyngeal AngiofibromaICD-O:9160/0Nasopharyngeal angiofibromas (or juvenile nasopharyngealangiofibromas) are rare benign tumours with anincidence of 0.5% of all head and neck tumours. Theyoccur exclusively in adolescent males and become clinicallyevident between 10 and 25 years of age with nosebleeds, respiratory distress, headaches or sometimesvisual disturbances. Nasopharyngeal angiofibromasarise from the posterior lateral wall of the nasal cavitynear the pterygo-palatine fossa at the superior marginof the foramen sphenopalatinum and extend into adjacentstructures such as maxillary, sphenoid or ethmoidsinuses and the nasal cavity. The most advanced casesshow intracranial extension [153, 203]. The blood supplyof nasopharyngeal angiofibromas comes from the externalcarotid artery with the internal maxillary artery asfeeding branch. In a minority of cases, the feeding vesselsare the sphenopalatine artery and the ascendingpharyngeal artery [75, 153]. Diagnosis of a nasopharyngealangiofibroma is based on clinical examinationand computer tomography, which shows two consistentfeatures: 1) localisation in the posterior nasal cavityand pterygopalatine fossa, and 2) bone erosions of the