Pathology of the Head and Neck

286 M.R. Canninga-Van Dijkepithelium with apocrine changes and containing gobletcells (Fig. 10.3). In the underlying stroma, chronic inflammatorycells may be present.10.2.3 Degeneration10.2.3.1 Pingueculaand Pterygium10Pingueculae are raised, localised, yellowish-grey lesionsthat occur in the bulbar conjunctiva, close to the limbuson the nasal or temporal side of the cornea. Pterygiaare similar in appearance and also develop in these areas,but involve the peripheral cornea, mostly the nasalside, as well. Pingueculae and pterygia are degenerativelesions causally related to prolonged actinic exposure.The lesions are often bilateral and occur in middleagedand elderly patients, especially in areas with highlevels of sunlight. On histologic examination both lesionsare identical. The essential feature is elastotic degenerationof the collagen, resulting in a subepithelialzone of amorphous, basophilic material (Fig. 10.4). Thismaterial stains black with the Elastica van Gieson stain(Fig. 10.5). In older lesions calcification can occur. Theoverlying epithelium may show a wide variety of changes,but most frequently it is thin, atrophic conjunctivalepithelium or acanthosis without cellular atypia. In theepithelium an actinic keratosis or even a squamous cellcarcinoma may develop [110].Since pingueculae are not progressive, they are seldomexcised. Pterygia are of more clinical importancebecause of their extension to the cornea.10.2.4 Inflammatory ProcessesThe conjunctiva is prone to inflammations with manydifferent causes, either infectious or as a part of a noninfectiousdermatologic or systemic disease. Usuallythese lesions do not cause diagnostic problems, but abiopsy can be useful in making the correct diagnosis[97]. In this chapter the inflammatory processes of theconjunctiva are divided into acute, chronic and granulomatous.The only lesions mentioned separately are ligneousconjunctivitis and lesions caused by Chlamydiainfections.Fig. 10.3. Conjunctival inclusion cyst: a cystic space is covered withnon-keratinising cuboidal epithelium, containing goblet cellsFig. 10.4. Pinguecula: amorphous, basophilic material in thestroma represents the elastotic degenerated collagen10.2.4.1 Acute ConjunctivitisIn acute conjunctivitis there is a rapid onset of a swollen,hyperaemic conjunctiva accompanied by increasedtear formation. There may be a watery (viral infections),fibrinous (bacterial infections) or mucoid (allergic reac-Fig. 10.5. Pinguecula: the elastotic collagen stains black in elasticastaining (Elastica van Gieson stain)