Pathology of the Head and Neck

Larynx and Hypopharynx Chapter 7 215Subglottic LH appears more frequently in girls, witha ratio of 2:1 [334]. A co-existence of haemangiomas ofthe skin and mucosa of the oral cavity and pharynx, aswell as in other organs [195, 337], may also be an importantindicator of disease.The gross appearance of the lesion ranges from a flatto polypoid, soft, compressible submucosal mass, pinkreddishto blue in colour. The lesion is usually one-sided,and is located in the posterolateral subglottic area. However,some haemangiomas are horseshoe-shaped and arepresent as a bilateral subglottic reddish swelling [195].The diagnosis is based on characteristic clinical featuresand endoscopic appearance. Biopsy should be avoidedbecause of an increased risk of excessive bleeding.Laryngeal haemangiomas of adults, which are usuallylocalised in the glottic and supraglottic region, areseen as inconspicuous, submucosal, reddish blue lesions.Common symptoms are hoarseness, dyspnoea and/orforeign body sensation [336].Histologically, subglottic LHs are divided into capillaryand cavernous forms. The majority of lesions areof the capillary type [334], consisting of the proliferatingcapillaries that infiltrate the surrounding submucosalstructures (Fig. 7.10) .Vascular channels may be of various sizes, lined withplump endothelial cells in which some regular mitosesmay be present. Vascular tissue is intertwined with fibroustissue and infiltrated with a variable amount ofinflammatory cells. Focally, depositions of haemosiderinmay be found in the fibrous stroma. It is importantto note that haemangiomas in infants are considerablymore cellular than adult ones [48]. The cavernous formof LH is less frequent, composed of proliferation of largeangiectatic vascular spaces, lined with thin, spindleshapedendothelial cells, and filled with erythrocytes.This type of lesion is more common in adults. Immunohistochemicalanalysis helps to confirm endothelial cellproliferations in both forms, with positivity for CD31,CD34 and factor XIIIa antigens.In differential diagnosis, various lesions of vascularorigin, such as the vascular type of the vocal cord polyp(VCP), pyogenic granuloma, intravascular papillaryendothelial hyperplasia and even angiosarcoma, mustbe considered. The vascular variant of VCP is usuallycharacterised by highly angiectatic vascular spaces surroundedby massive leakage of fibrin as amorphous hyalinepink material, a feature not characteristic of capillaryhaemangioma. Pyogenic granuloma is diffuselyinfiltrated with neutrophils, which is not the case inhaemangiomas, if the covering epithelium is intact. Papillaryendothelial hyperplasia represents an organisationof thrombosis with papillary proliferation of the endothelialcells, which is not a striking histological featureof haemangioma. The distinction between the cellularvariant of haemangioma and angiosarcoma may sometimesbe problematic. However, anastomoses of the vascularchannels, lined with considerably pleomorphic endothelialcells with evident pathologic mitoses, certainlyfavour a diagnosis of angiosarcoma [48].Subglottic LH of infants is generally a self-limited butpotentially fatal lesion, causing progressive airway obstruction.Various treatment modalities have been proposed,including expectant policy, systemic steroids andinterferon alfa-2a applications, CO 2 laser excision andtracheostomy, but no very promising treatments are yetavailable [139, 196, 328].7.6.4 ParagangliomaICD-O:8680/1Paragangliomas are rare benign tumours, originatingfrom the anatomically dispersed neuroendocrinesystem (paraganglia), characterised by similar neurosecretorycells derived from the neural crest andassociated with autonomic ganglia. The extra-adrenalportions of the paraganglia are divided into fourgroups according to their distribution and innervations:branchiomeric, intravagal, aortosympatheticand visceral autonomic. The paraganglia of the larynxare part of the branchiomeric paraganglionic system,together with the jugulotympanic, carotid body,subclavian, coronary, aorticopulmonary, pulmonaryand orbital paraganglia [18].Laryngeal paragangliomas (LP) are extremely rare,almost always benign tumours originating in the superiorand inferior paired paraganglia. The former are localisedin the false vocal cords, the latter in the vicinityof the cricoid cartilage [18, 255]. Patients are usually ofmiddle age with a median age of 47 years. Surprisingly,compared with other neuroendocrine tumours, the LPsare three times more common in women. The predominantsite is the supraglottic (82%), followed by the subglotticin 15% and the glottic area in 3% of cases. Signsand symptoms are mainly related to the localisation andsize of the tumour [45, 289]. LPs are rarely functional,multicentric or associated with other head and neckparagangliomas.Macroscopically, the tumour usually presents as arounded submucosal mass with an intact covering mucosa,ranging in size from 0.5 to 6 cm [18]. The tumoursare firm; on the cut surface they may be homogenous ornodular, from pink to tan and dark red in colour. Prominentvascularity of the tumour may cause abundantbleeding during biopsy.Histologically, LPs are composed of two cell types:chief and sustentacular or supporting cells. The chiefcells of epithelioid appearance are packed into roundnests showing an organoid pattern, surrounded byhighly vascular fibrous tissue (i.e. Zellballen; Fig. 7.11a) .However, the characteristic cell nests may be squeezedand not apparent in a small biopsy specimen. The chief