Pathology of the Head and Neck

304 M.R. Canninga-Van DijkFig. 10.27. Hidrocystoma: cystic space lined with flattened epitheliumwith a myoepithelial baseFig. 10.28. Chalazion: optical empty spaces surrounded by histiocytesforming granulomas. The infiltrate also contains lymphocytesand neutrophils1010.7.2 Inflammatory ProcessesA very common inflammatory condition of the eyelidsis a chalazion. Furthermore, many inflammatory skindiseases can involve the periorbital region. Periorbitaleczema may be an expression of a constitutional disease,an irritant or allergic dermatitis. Other inflammatorydermatoses that can involve the eyelids are seborrheicdermatitis, psoriasis, rosacea and dermatomyositis.Other causes of inflammation of the eyelids include bacterial,fungal and viral infections.10.7.2.1 Chalazionand Other Ruptured CystsChalazia are very common. The clinical presentation isusually very typical, with an acute swelling in the tarsalconjunctiva. In a few days the swelling becomes afirm nodule. Excision or excochleation is the treatmentof choice. Because of the typical clinical presentation,many ophthalmologists will not offer the material forroutine histological examination. Chalazia are causedby the obstruction of the duct of a small (Zeis) or larger(Meibomian) sebaceous gland. A small retention cyst isformed and rupture of this cyst causes the escape of fattyproducts into the surrounding tissues. The fatty materialtriggers an acute inflammatory reaction first, followedby a chronic granulomatous reaction (Fig. 10.28).In the very late stages of chalazia, fibrosis and scarringcan be seen. The presence of fatty cells or even largeroptical empty spaces within a granulomatous reaction ischaracteristic of a chalazion. The only other conditionswith similar lipogranulomatous reactions are leakage ofimplants (for example silicon) and dermatitis artefacta.If patients with dermatitis artefacta use oily fluids to inject,the histological picture is identical to that of a chalazion.All other cysts (dermoid, epidermal and hidrocystomas)can rupture. The wall of the cyst is sometimes nolonger identifiable. The presence of small pieces of thecontent of the former cyst (hair, keratin) in multinucleatedgiant cells proves the diagnosis of an inflamed andruptured cyst.10.7.2.2 Deep Granuloma AnnulareGranuloma annulare usually occurs on the dorsum ofthe hands and the lower arms. It is considered to be acutaneous reaction pattern, most frequently associatedwith diabetes mellitus. However, in children the deepvariant of granuloma annulare is a benign, relativelycommon dermatosis, not related to systemic disease. Ingranuloma annulare of childhood lesions typically occuron the extremities and resolve spontaneously overa period of several months to years. Localised facial involvement,sometimes with involvement of the eyelids, israre. The clinical relevance is that granuloma annulare,presenting in the periocular region, may mimic otherlesions. This diagnosis should be considered for any acquiredpapules of the periorbital area, especially if thereis a history of antecedent trauma. Unnecessary surgicalexcision can then be avoided. Histology shows deep fociof degeneration of collagen, surrounded by histiocytes.Often there is increased dermal mucin.