Pathology of the Head and Neck

248 L. Michaels8tinct and predominant “plasmacytoid” appearance ofthe epithelial cells of the neoplasm may be displayed[92].No myoepithelial layer is seen. PAS and Alcian bluestains may be positive for mucoprotein secretion in thegland lumina and in the cytoplasm of the tumour cells.Benign glandular tumours of the middle ear were notdescribed until 1976 [26, 45]. It was soon reported that aglandular tumour of the middle ear, otherwise apparentlyidentical to an adenoma, was Grimelius positive andon electron microscopy, showed numerous membraneboundgranules [75]. The use of immunohistochemistryfrom 1987, further confirmed the presence of neuroendocrinefeatures in some of these neoplasms [108]. In an investigationof five cases of adenoma of the middle ear bylight microscopic methods, immunohistochemistry andtransmission electron microscopy, the glandular areas ofthe tumour in each patient showed bidirectional mucinousand neuroendocrine differentiation. This was demonstratedby the presence of two cell types. Apically situateddark cells contained mucous granules; these cellswere negative for neuroendocrine markers. Basally situatedcells contained neuroendocrine granules; these cellswere positive for neuroendocrine markers – vasoactiveintestinal polypeptides or neuron-specific enolase [120].It seems likely that there is but a single benign glandularneoplasm of the middle ear, the adenoma. Neuroendocrineas well as mucinous differentiation is frequent,perhaps universal, in these neoplasms. Contraryto what has been suggested by some authors there is noevidence that the presence of neuroendocrine differentiationreflects a more aggressive potential in adenomas,which are benign tumours.8.3.2.3 Papillary TumoursFig. 8.14. Aggressive papillary tumour of the middle earICD-O:8260/0, 8260/3Aggressive papillary tumour is characterised by a papillary,non-stratified epithelial histological pattern thatshows aggressive, often invasive behaviour. Forty-sixcases in which the temporal bone was affected by thisneoplasm were collected from the literature in 1994 [31].Some of these had been reported as low-grade adenocarcinomaof probable endolymphatic sac origin (seebelow and also Sect. 8.4.2.3) [41]. I have reviewed eachof the case reports cited in these two studies togetherwith cases reported in the literature more recently, andthis has produced a total of 25 cases in which the middleear was definitely involved in the neoplasm. Some of theliterature sources reported more than one case [1, 9, 10,21, 31–33, 35, 38, 41, 50, 86, 88, 109, 111, 118].The 25 literature cases with this middle ear neoplasmcomprised 18 females and 7 males. The age-range at timeof diagnosis was between 16 and 55 years with a medianage of 33 and a mean age of 34 years. In many of the cases,however, the patient had already suffered symptomssubsequently ascribable to the tumour for some yearswhen the diagnosis was made, so that the age of onsetmay be considerably younger than is suggested.The tumour is found in any area of the middle ear,including the mastoid process and air cells and may fillthe tympanic cavity. In all of the described cases, exceptthree [21, 109, 118], there was extensive invasion outsidethe middle ear, involving the apical portion of the petrousbone in most and in a few the tumour reached thecerebellopontine angle and the cerebellum.It has been suggested that cases of aggressive papillarymiddle ear tumour with widespread involvement ofthe temporal bone may arise from a primary papillaryadenocarcinoma of the endolymphatic sac (endolymphaticsac tumour, low-grade adenocarcinoma of probableendolymphatic sac origin) [41]. The frequent associationof papillary tumours in the middle ear with apicalpetrous bone neoplasia of the same type, the similarityof the histological appearances of the neoplasmin the two regions and the association of some cases ofpapillary tumours in both regions with von Hippel-Lindaudisease would seem to favour this concept. Such anorigin has not yet been confirmed by autopsy study. Indeed,in the single description of the pathological changesof aggressive papillary tumour of the middle ear in anautopsy-acquired temporal bone, widespread depositsof tumour at inner ear sites are depicted, but no mentionis made of involvement of the endolymphatic sacor duct [100]. Thus, a middle ear origin for some casesof this neoplasm at least has not been definitely excluded.Whatever the site or sites of origin of this tumour, itshould be recognised that papillary epithelial tumour ofthe middle ear is an aggressive neoplasm, in contrast tothe non-papillary adenoma of the middle ear, which isquite benign [73].In view of the association of some cases of von Hippel-Lindaudisease with aggressive papillary middle eartumours it is suggested that the clinical assessment of