basement membrane material is produced, recapitulating the lens capsule (Fig 13-2). The nodule formed is usually present at birth and enlarges slowly. Complete excision is the usual treatment.

Dermoid Cyst

Dermoid cysts may occur in the eyelid, but they are more common in the orbit and are discussed in Chapter 14.

Figure 13-2 Phakomatous choristoma of the eyelid. The dermis displays a disorganized proliferation of lens epithelium and occasional “bladder” cells (arrows). Note the large amount of eosinophilic material that represents lens nuclear/cortical

proteins. (Courtesy of Nasreen A. Syed, MD.)

Inflammations

Infectious

Depending on the causative agent, infections of the eyelids may produce disease that is localized (eg, hordeolum), multicentric (eg, papillomas), or diffuse (cellulitis). Routes of infection may be primary

inoculation through a bite or wound, direct spread from a contiguous site such as a paranasal sinus infection, or hematogenous dissemination from a remote site. Infectious agents may be

bacterial, such as Staphylococcus aureus in hordeolum and infectious blepharitis viral, such as molluscum contagiosum due to a poxvirus

fungal, such as blastomycosis, coccidioidomycosis, or aspergillosis

Hordeolum

Also known as a stye, hordeolum is a primary, acute, self-limited inflammatory process typically involving the glands of Zeis and, less often, the meibomian glands of the eyelids. A small abscess, or focal collection of neutrophils and necrotic debris (pus), forms at the site of infection. Lesions may drain spontaneously or require surgical drainage.

Cellulitis

The diffuse spread of acute inflammatory cells through tissue planes is known as cellulitis. Preseptal cellulitis involves the tissues of the eyelid anterior to the orbital septum, the fibrous membrane connecting the borders of the tarsal plates to the bony orbital rim. The condition can be due to infected skin lesions or bacterial infection of the paranasal sinuses. Histologically, there is neutrophilic infiltration of the soft tissues, accompanied by interstitial edema and, occasionally, necrosis (Fig 13-3).

Figure 13-3 Neutrophils (arrows) dissect between the skeletal muscle fibers of the orbicularis in this biopsy of a preseptal cellulitis of the eyelid.

Viral infections

Human papillomavirus may infect the skin of the eyelids and typically manifests as verruca vulgaris, commonly known as a wart. Clinically, it is usually an elevated papillary lesion. Histologically, the lesions demonstrate hyperkeratosis and acanthosis and exhibit a papillary growth pattern. Infected cells may demonstrate cytoplasmic clearing (koilocytosis). A mixed inflammatory infiltrate is typically present in the superficial dermis (Fig 13-4).

Figure 13-4 A, Verruca vulgaris is a form of infection of the eyelid with human papillomavirus (HPV). The lesion has a papillary growth pattern with fingerlike projections. B, Occasional koilocytes with nuclear contraction and cytoplasmic clearing

are present (arrow). (Courtesy of Nasreen A. Syed, MD.)

Molluscum contagiosum is caused by a member of the poxvirus family. Dome-shaped, waxy epidermal nodules with central umbilication form and, if present on the eyelid margin, may cause a secondary follicular conjunctivitis (Fig 13-5). Histologically, the lesions are distinctive, with a nodular proliferation of infected epithelium producing a central focus of necrotic cells that are extruded to the skin surface. As the replicating virus fills the cytoplasm, the nucleus is displaced peripherally by large viral inclusions (molluscum bodies) and finally disappears as the cells are shed (Fig 13-6).

Noninfectious

Chalazion

A chalazion is a chronic, often painless nodule of the eyelid that occurs when the lipid secretions of the meibomian glands or, less often, the glands of Zeis are discharged into the surrounding tissues, inciting a lipogranulomatous reaction (Fig 13-7). Because the lipid is dissolved by solvents during routine tissue processing, histologic sections show histiocytes and multinucleated giant cells enveloping optically clear (“lipid dropout”) spaces. Lymphocytes, plasma cells, and neutrophils are also often present.