Pathology of the Head and Neck

134 S. Di Palma · R.H.W. Simpson · A. Skalova · I. Leivounderlying process appears to be a disorder of salivarygland innervation. It is also seen in malnutrition,chronic alcoholism, bulimia, liver cirrhosis and hasbeen linked to some drugs, such as antihypertensiveagents [62].It is rarely biopsied, but histologically there is enlargementof the serous acinar cells (two or three timesthe normal size) and slight compression of the duct systemby the swollen acini.55.5.3 Adenomatoid Hyperplasiaof Mucous Salivary GlandsThis nodular hyperplastic lesion is usually asymptomatic,often being noted on routine dental examination.Most cases occur on the palate, but sometimes other minorglands can be involved [25]. It can affect all ages,although most patients are between 30 and 60 yearsold. There is a slight male predominance. Examinationreveals nodular mucosal swellings up to 30 mm in diameter.The aetiology is unknown, but possible relevantfactors include local trauma due to dentures or tobaccosmoking. The main histological feature of adenomatoidhyperplasia is the presence of hypertrophic andhyperplastic mucous lobules of minor salivary glands.Inflammation, fibrosis and cytological abnormality arenot usually seen.5.5.4 Irradiation ChangesSalivary glands are very sensitive to radiation, and xerostomiais a common complication. Acute radiationinjury of salivary glands manifests with swelling, vacuolationand necrosis of acinar cells. Initial acute inflammatoryresponse is later followed by chronic sclerosingsialadenitis characterised by loss of acini, focal squamousmetaplasia, and fibrosis. When all the salivaryglands are involved, the loss of saliva is progressive andirreversible.5.5.5 Tissue ChangesFollowing Fine Needle AspirationFig. 5.3. Focal oncocytosis of the parotid gland. Some ducts andacinar cells show cytoplasmic oncocytic featuresFine needle aspiration (FNA) is an important techniquein the investigation of salivary disease, particularly tumours,but the procedure itself can have adverse effects,causing difficulties in histological assessment and evensimulating malignancy. The effects are classified as tissueinjury with repair, infarction and reactive pseudomalignantchanges [28]. Some or all of these can occurin any tumour [126] including pleomorphic adenoma,but are most frequent in Warthin’s tumour, where infarctionmay be total and squamous metaplasia florid[55]. Possible causes include trauma by the needle [55]and an increased sensitivity of oncocytic cells to hypoxia[28].5.6 Oncocytic LesionsOncocytic change is where cells develop intensely eosinophilicgranular cytoplasm due, to increased numbers ofmitochondria [180].5.6.1 Focaland Diffuse OncocytosisFoci of oncocytic metaplasia, usually of ducts, but occasionallyalso acini, occur with increasing frequencywith advancing age (Fig. 5.3). In contrast, diffuse oncocytosisof the parotid is extremely rare. Microscopicexamination shows oncocytic metaplasia of ducts andacini involving virtually the whole gland. As with mostother oncocytic lesions, diffuse oncocytosis comprisestwo types of cells, light and dark. The former are largeand round or polygonal and have finely granular, pinkcytoplasm and a single vesicular nucleus. The darkcells are usually more sparse and have deeply eosinophilic,compressed cytoplasm and densely hyperchromaticnuclei.5.6.2 Ductal OncocytosisOncocytic metaplasia of ducts often with cystic dilation(also known as oncocytic papillary cystadenoma) occursmainly in the minor glands, particularly the larynx, and