Chévez-Barrios P. Frozen section diagnosis and indications in ophthalmic pathology. Arch Pathol Lab Med. 2005;129(12):1626– 1634.

Dermal Neoplasms

Capillary hemangiomas are common in the eyelids of children. They usually appear at or shortly after birth as a bright red lesion, grow over weeks to months, and involute by school age. Intervention is reserved for those lesions that affect vision because of ptosis or astigmatism, promoting amblyopia.

Figure 13-19 Squamous cell carcinoma. A, Clinical appearance. Note the focal loss of lashes and scaly appearance of the lower eyelid. B, Note the tumor cells (T) invading the dermis. C, Keratin (asterisk) is produced in this well-differentiated

squamous cell carcinoma. (Part A courtesy of Keith D. Carter, MD.)

The histopathologic appearance depends on the stage of evolution of the hemangioma. Early lesions may be very cellular, with solid nests of plump endothelial cells and correspondingly little vascular luminal formation. Established lesions typically show well-developed, flattened, endothelium-lined capillary channels in a lobular configuration (Fig 13-20). Involuting lesions demonstrate increased fibrosis and hyalinization of capillary walls with luminal occlusion.

Figure 13-20 Capillary hemangioma. A, Infant with multiple capillary hemangiomas. B, Note the small capillary-sized vessels and the proliferation of benign endothelial cells. (Part A courtesy of Sander Dubovy, MD.)

Appendage Neoplasms

Syringoma

Syringoma is a common benign lesion of the lower eyelid and typically manifests as multiple tiny papules. Syringomas result from a malformation of the eccrine sweat gland ducts. Histologically, syringomas consist of multiple, comma-shaped or round ductules lined with a double layer of epithelium and containing a central lumen, often with secretory material (Fig 13-21).

Sebaceous hyperplasia

Sebaceous hyperplasia is an uncommon benign lesion of the eyelid and face. Clinically, it appears as a small, yellow papule. Histologically, it is typically a single enlarged sebaceous gland with numerous glandular lobules attached to a single central duct (Fig 13-22).

Sebaceous adenoma

Sebaceous adenoma is a rare benign lesion of the eyelid that typically manifests as a yellow, circumscribed nodule. Histologically, it is composed of multiple sebaceous lobules that are irregularly shaped and incompletely differentiated (Fig 13-23). Muir-Torre syndrome should be considered when sebaceous adenoma is diagnosed (see Table 13-3).

Sebaceous carcinoma

A sebaceous carcinoma most commonly involves the upper eyelid of elderly persons. It may originate in the meibomian glands of the tarsus, the glands of Zeis in the skin of the eyelid, or the sebaceous glands of the caruncle. Clinical diagnosis is often missed or delayed because of this lesion’s propensity to mimic a chalazion or chronic blepharoconjunctivitis (Fig 13-24).

Figure 13-21 Histologically, syringoma is composed of small, epithelial-lined ductules that are round or comma-shaped

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

Figure 13-22 Sebaceous hyperplasia. Numerous sebaceous lobules (arrowheads) surround a hair follicle (arrow). (Courtesy of

Nasreen A. Syed, MD.)

Figure 13-23 Sebaceous adenoma. Sebaceous lobules demonstrate focal proliferations of basophilic (blue) sebocytes. This lesion is most commonly associated with Muir-Torre syndrome. (Courtesy of Nasreen A. Syed, MD.)

Histologically, well-differentiated sebaceous carcinomas are readily identified by the microvesicular foamy nature of the tumor cell cytoplasm (Fig 13-25A). Moderately differentiated tumors may exhibit some degree of sebaceous differentiation. Poorly differentiated tumors, however, may be difficult to distinguish from the other, more common epithelial malignancies. The demonstration of lipid within the cytoplasm of tumor cells by special stains, such as oil red O or Sudan black, is diagnostic, but it must be performed on tissue prior to processing and paraffin embedding.

When sebaceous carcinoma is suspected clinically, the pathologist should be alerted so that frozen section slides can be generated for lipid stains. Another feature, characteristic of but not pathognomonic for sebaceous cell carcinoma, is the dissemination of individual tumor cells and clusters of tumor cells within the epidermis or conjunctival epithelium, known as pagetoid spread (Fig 13-25B). Another pattern in the conjunctiva is that of complete replacement of conjunctival epithelium by tumor cells, or sebaceous carcinoma in situ (Fig 13-25C). A rare variant of sebaceous carcinoma involves only the epidermis and conjunctiva without demonstrable invasive tumor.

Figure 13-24 Sebaceous carcinoma. A, Note the eyelid erythema suggesting blepharitis. Note also the loss of eyelashes and the irregular eyelid thickening. B, This lesion mimics a chalazion of the lower eyelid. Focal lash loss is present.

courtesy of Roberta E. Gausas, MD.)