Pathology of the Head and Neck

46 A. Cardesa · L. Alos · A. Franchi22.8.7 Cocaine AbuseCocaine abuse may be associated with severe nasalnecrotising inflammation [225]. Endoscopically, there isatrophy of the inferior and middle turbinates and ulcerationof the nasal septum. Histologically, areas of acuteand chronic inflammation are found; however, vasculitisis minimal or absent and granulomas may be present.The lesion may be confused with Wegener’s granulomatosis.2.8.8 Local Steroid InjectionsA granulomatous lesion of the nasal mucous membraneshas been observed in patients treated with injections ofsteroid preparations [272]. There is a central deposition ofamorphous material bordered by histiocytes and foreignbody giant cells. Occasional particles of birefringent crystallinematerial may be present. Special stains should beperformed to exclude the presence of micro-organisms.2.9 Benign Epithelial Neoplasms2.9.1 Sinonasal PapillomasSinonasal papillomas may be divided into squamous cellpapillomas of the nasal vestibule and schneiderian papillomasof the nasal cavity and paranasal sinuses [121].The first are covered by epithelium of the skin surface.The latter are lined by well-differentiated respiratoryepithelium (referred to as the schneiderian membrane)and comprise three histopathological types: exophytic,inverted and oncocytic. The histopathological featuresthat clearly differentiate between the three types of schneiderianpapillomas have been well documented [173].Human papilloma virus (HPV) types 6 and 11 are involvedin the pathogenesis of exophytic papillomas, butnot in the other two variants of schneiderian papillomas[35, 89, 128]. All oncocytic papillomas examined havebeen HPV-negative [35, 128, 221].2.9.1.1 Squamous Cell PapillomaICD-O:8052/0Squamous cell papillomas are located in the nasal vestibuleand are formed by keratinising stratified squamousepithelium of the skin surface [122]. They are exophyticand consist of a thickened layer of differentiated squamousepithelium, without evidence of atypia or mitoses,which is supported by arborescent stalks of fibrovascularstroma. Varying degrees of keratinisation are presentand either hyperkeratosis, parakeratosis or both may beseen. They are benign, rarely recur after simple excision.Its main differential diagnosis is the exophytic schneiderianpapilloma.2.9.1.2 Exophytic PapillomaICD-O:8121/0Exophytic papilloma, also known as “everted” or “fungiform”papilloma, is a single, warty tumour measuringup to 1.5 cm in diameter, arising most frequentlyat the nasal septum and only very rarely in the lateralnasal walls or in paranasal sinuses [122]. Males are predominantlyaffected. Patients tend to be younger thanwith other types of schneiderian papilloma. Exophyticpapillomas are almost always unilateral [54]. No side ispreferred and bilaterality is exceptional. The tumour iscomposed of branching papillary structures, with papillaecovered by stratified non-keratinising squamousepithelium, admixed with intermediate or transitionalcells and with ciliated respiratory epithelium that containsinterspersed mucin-secreting cells. Koilocytosisis not infrequently found in the squamous epithelium.Seromucinous glands are abundantly found when theunderlying submucosa is removed.The two main differential diagnoses are invertedpapilloma and oncocytic papilloma. Neither the invaginatedpattern of growth of inverted papillomas nor theoncocytic columnar epithelium of oncocytic papillomasare found in exophytic papillomas [173]. Cylindrical cellcarcinoma can be easily ruled out by the lack of atypiaand invasion. Wide surgical excision is the best choiceof treatment to avoid recurrences. Recurrences occur inabout 20–40% of cases, which is less than in invertedpapillomas. Malignant transformation almost never occursin exophytic papillomas.2.9.1.3 Inverted PapillomaICD-O:8121/0Inverted papilloma is the most common type of schneiderianpapilloma. This lesion occurs almost exclusivelyin the lateral wall of the nasal cavity and in the paranasalsinuses, although on rare occasions it may alsoarise on the nasal septum [226]. Grossly, they frequentlyhave a polypoid appearance, but they differ from nasalpolyps of the common type by their histological features.Inverted papillomas are composed of invaginatingcrypts, cords and nests covered by non-keratinisingsquamous epithelium, which alternates with columnarciliated respiratory epithelium and with intermediate ortransitional epithelium (Fig. 2.4a). This newly formedduct system is similar to the embryonic developmentof the nasal mucosa [240]. The multilayered epitheliumtypically contains mucous cells and mucin-filled micro-