Layers of the skin

The eyelid skin is the thinnest skin in the body. This skin contains two layers:

The epidermis is the continually dividing superficial layer of the skin that covers the body. The dermis is the deep layer of the skin. Other than in the eyelid, there is a layer of subcutaneous fat deep to the dermis (Figure 11-1). The eyelid skin is tightly bound to the underlying orbicularis muscle.

Figure 11-1 The skin and appendages. (A) The layers of the skin. (B) The adnexa of the skin.

Cells destined to become the surface of the skin start as undifferentiated basal cells along the junction of the epidermis and dermis. As these epidermal cells differentiate and move toward the skin surface, they lose their nuclei, flatten, and become keratinized. The most common skin malignancy, basal cell carcinoma, arises from these undifferentiated cells in the basal layer. Because these cells are not producing keratin, basal cell carcinomas do not have excessive keratin production, or hyperkeratosis, as part of their clinical picture. In contrast, squamous cell carcinoma arises from more superficial epidermal skin cells, known as squamous cells, which produce keratin. Consequently, squamous cell carcinoma is associated with hyperkeratosis.

Appendages of the skin

The dermis contains the skin appendages or adnexa (Figure 11-1). The adnexa are the specialized tissues added on to the skin including:

Each adnexal tissue contains specialized cells that may create both solid or cystic cell proliferations. Common tumors arising from the adnexa include chalazia and various cysts. Chalazia arise from the specialized sebaceous glands of the tarsal plate, the meibomian glands. The most common cyst in the periocular area, the apocrine hidrocystoma, arises from the apocrine sweat glands along the lid margin. We will talk about this later. For now, just remember that there can be solid and cystic tumors of each adnexal tissue.

The dermis also contains a number of other tissues including vascular, fibrous, and neural elements. Each of these tissues may give rise to tumors that are rarely seen in the eyelids. You are not likely to see many of these lesions so they will not be covered in this text (Box 11-1).

Characteristics of malignancy

This is the most important section of this chapter. Remember that the main goal of evaluating a lid lesion is to rule out malignancy. The most common skin malignancy is basal cell carcinoma, which arises from the epidermis. Basal cell carcinoma represents more than 90% of lid malignancies. If you can recognize basal cell carcinoma, you will be able to recognize the majority of skin cancers affecting the eyelids. Review the characteristics of skin malignancy listed in Box 11-2. Remember these characteristics and you will have little difficulty in diagnosing cutaneous malignancies.

Pearly borders and telangiectasia

Pearly borders and telangiectasias are pathognomonic for basal cell carcinoma. Heaped up edges often surround an area of central ulceration. With the slit beam focused on the edge of these lesions, there appears to be a translucency to the lesion itself allegedly from the proliferating cells in the basal layer of the epidermis. Telangiectasias refer to the dilated and irregular vessels accompanying the pearly margins of the basal cell carcinoma. Review the photographs of typical basal cell carcinomas and make sure in your mind that you recognize all the features of epithelial cell malignancy (Figure 11-2).

Figure 11-2 Typical examples of basal cell carcinoma. (A) Note the classic features—pearly margins and telangiectasias—in this small nodular basal cell carcinoma on the upper eyelid margin. (B) Pearly margins and an irregular shape are prominent in this basal cell carcinoma. Note the central ulceration and loss of the lid margin architecture. (C) This basal cell carcinoma is pearly white and has typical telangiectasias. Note the indurated thickening of the lid margin. The eyelashes are gone, and the lid margin is altered. The tumor margins are not distinct in this example. (D) A more nodular basal cell carcinoma with distinct pearly margins, telangiectasias, and central ulceration. (E) Nodular basal cell carcinoma with crusting over central ulceration. (F) The most obvious feature of this basal cell carcinoma is ulceration. (G and H) Morpheaform or nodular type. This type of basal cell carcinoma has less apparent clinical margins. The telangiectasias in (G) and thickening of the skin strongly suggest a basal cell carcinoma and should prompt a biopsy. The sclerosing changes in (H) pulling the eyelids away from the eye suggest a biopsy. The defect after excision of these diffuse lesions may be large.

All the characteristics of malignancy are not always seen in each tumor. When one or more characteristics of malignancy exist, consider a biopsy.

Basal cell carcinoma

Basal cell carcinoma, like squamous cell carcinoma, is related to ultraviolet or actinic damage. Consequently, basal cell carcinoma is most common in fair-skinned patients whose skin tends to burn rather than tan in the sun. The lower lid and medial canthus are the most commonly affected locations, probably related to getting more sun exposure than the upper lid. The hallmarks of basal cell carcinoma are pearly borders with telangiectasia. Central ulceration is common. The lesions are not painful and not tender to touch. The border and contour of the lesion are generally irregular. Destruction of normal lid architecture occurs when the lesion involves the lid margin. Lashes are often lost. Hyperkeratosis is not a common finding associated with basal cell carcinoma, because these tumors arise from cells in the basal layer of the epidermis.

Basal cell carcinoma and squamous cell carcinoma may be recognized by the company that they keep. Other signs of actinic damage to the skin, especially in a patient with light skin and blue eyes, should heighten your suspicion of a skin malignancy. Look for signs of sun damage on your patient’s face to help you diagnose basal cell carcinoma (Figure 11-3).

Figure 11-3 (A) Basal cell carcinoma with diffuse margins. Note light irises and weathered skin on cheek. (B) Large defect after excision.

A rare genetic disorder, basal cell nevus syndrome, predisposes patients to multiple basal cell carcinomas. This autosomal dominant syndrome, also known as Gorlin’s syndrome, is also associated with palmar pits, jaw cysts, and skeletal abnormalities.

Squamous cell carcinoma

Squamous cell carcinoma may resemble basal cell carcinoma clinically. Although differentiating between these two lesions may not always be clinically possible, there should be little doubt about the presence of an epithelial malignancy based on the characteristics outlined above. Squamous cell carcinoma is much less common than basal cell carcinoma, representing less than 5% of lid tumors. If you have to guess the diagnosis, you should guess basal cell carcinoma because it is so much more common.

Squamous cell carcinoma can appear as a nodule or an indurated plaque with some hyperkeratosis. Often the scaly skin will fall off—strongly suggesting a squamous cell cancer or its precursor, actinic keratosis (discussed later in this chapter). Ulceration is sometimes present. Generally, the pearly margins and telangiectasia of basal cell carcinoma are not seen.

Squamous cell carcinoma is usually more aggressive than basal cell carcinoma. The margins of squamous cell carcinoma may be diffuse, resulting in a large area of subclinical tumor involvement (Figure 11-4). Neurotrophic spread (along nerves) occurs in squamous cell carcinoma but is uncommon in basal cell carcinoma. Squamous cell carcinoma in the periocular area with the presence of cranial nerve palsy suggests neurotrophic spread into the cavernous sinus.

Figure 11-4 Recurrent squamous cell carcinoma. Note the large size, diffuse margins, and hyperkeratinization. This lesion was considered unresectable because of the size and degree of neurotrophic spread. The patient underwent a course of radiation therapy.

Like basal cell carcinoma, squamous cell carcinoma arises in sun-damaged skin. The features of cutaneous actinic damage, such as deep wrinkles, skin thinning, generalized telangiectasia, and mottled pigmentation, may be seen (see Figure 11-19). Scaling keratotic lesions, actinic keratoses, the precursors of squamous cell carcinoma, are often present.

Keratoacanthoma

Keratoacanthoma is considered to be a low-grade squamous cell carcinoma. This tumor has a characteristic appearance different than that of most squamous cell carcinomas. A large lesion with a central crater filled with a keratin plug is typical. The lesion often appears in a few weeks and may spontaneously resolve. This lesion is discussed under the section, “Sun-Damaged Skin and Related Conditions.” You will see an illustration of this later.

Malignant tumors of the dermis are very rare and are not considered here. The dermis contains the adnexa of the periocular skin. Sebaceous cell carcinoma is the most common adnexal malignancy and is discussed next.

Sebaceous glands in the periocular area

Basal cell, squamous cell, and sebaceous cell carcinomas comprise greater than 95% of the malignancies of the eyelids. Sebaceous cell carcinoma is rare, representing between 1% and 5% of eyelid cancers. Sebaceous cell carcinoma arises within the sebaceous glands of the skin and therefore is referred to as an adnexal malignancy. As a reminder, the sebaceous glands in the periocular area are the following:

The presence of specialized sebaceous glands in the periocular area such as the meibomian glands and glands of Zeis makes the occurrence of sebaceous cell carcinoma in the periocular area more common than anywhere else in the body.

Clinical characteristics

Sebaceous cell carcinoma has no characteristic appearance; consequently, it is known as a “masquerader.” You won’t see many sebaceous cell cancers, but be suspicious if you see a unilateral blepharoconjunctivitis or a chronic or recurrent chalazion. In my experience, the classic recurrent chalazion is the more unusual presentation. An inflamed or swollen lid with conjunctivitis is more common. This blepharoconjunctivitis may present as a chronic condition (Figure 11-5). In some patients, many medical or surgical treatments will have been tried without relief, and the diagnosis of sebaceous cell carcinoma will not have been considered. Biopsy should be performed for chronic unilateral blepharoconjunctivitis or recurrent chalazia. In some cases, the conjunctival spread will predominate, so don’t forget to evert the eyelid. In other patients, sebaceous cell carcinoma may present as a more subtle thickening of the lid and lid margin (Figure 11-6). You should consider the diagnosis if you see a lid margin lesion that appears to arise from or extend over the margin onto the tarsal conjunctiva. The presence of any yellowish material within a malignant-appearing lesion should suggest the diagnosis of sebaceous cell carcinoma.

Figure 11-5 Sebaceous cell carcinoma presenting as an advanced unilateral chronic blepharoconjunctivitis.

Figure 11-6 Sebaceous cell carcinoma. Note the subtle thickening of the lid margin. These lesions often have a yellowish hue. This is seen in thin lines along the eyelid margin, giving a “tigroid” appearance to the thickened tissue.

Biopsy technique

Full-thickness lid biopsy has been recommended for the diagnosis of sebaceous cell carcinoma. When there is diffuse thickening of the lid with no obvious mass, it is a good idea to do a full-thickness lid biopsy. A full-thickness specimen gives the pathologist an opportunity to see the architecture of both affected and normal lid tissues, including the conjunctival epithelium. If a large mass is present, a generous incisional biopsy of the mass itself is usually diagnostic and a full-thickness biopsy is not necessary. Small biopsies of conjunctiva alone may be difficult to interpret. Oil red-O stain on fresh tissue has also been recommended for the diagnosis of sebaceous cell carcinoma. Although oil red-O does stain the sebaceous material within the tumor, the histologic and cytologic features of the tumor (including the typical foamy cytoplasm seen in the dysplastic sebaceous cells) are diagnostic in most cases without special staining.

Remember that sebaceous cell carcinomas are rare tumors. If you suspect a sebaceous cell carcinoma, be sure to let the pathologist know. General and dermatologic pathologists see few, if any, of them. When there is any question about the diagnosis of a sebaceous cell carcinoma, consultation with an ophthalmic pathologist is appropriate. He or she is likely to have the most experience and should be able to provide the most accurate diagnosis.

Unusual growth characteristics

Sebaceous cell carcinoma has two unusual growth characteristics that make removal difficult. The first is pagetoid spread. Intraepithelial sebaceous cell carcinoma may spread superficially over large areas of the conjunctiva. Secondly, sebaceous cell carcinoma appears to arise from multifocal noncontiguous tumor origins. These characteristics make excision of sebaceous cell carcinoma more complicated than that of the more common cutaneous malignancies. Basal cell and squamous cell carcinomas arise from a single origin and tend to spread radially. Clinical margins can be approximated and then confirmed with frozen sections. With sebaceous cell carcinoma, the true pathologic margins are often not clinically visible because of the pagetoid spread. Noncontiguous tumor origins make intraoperative margin confirmation of tumor removal unreliable, because the surgical margin may be free of tumor, but another focus of tumor may be just beyond the first margin.

Tumor excision

For these reasons, excision of sebaceous cell carcinoma is somewhat specialized. Preoperatively, map biopsies of the conjunctiva are done to determine the probable peripheral extent of any pagetoid spread. From the results of these permanent section biopsies, a surgical excision is planned.

At the time of excision, generous margins are taken to include the involved areas of the tarsus, lid margin, skin, and conjunctiva. There is some controversy about the usefulness of frozen sections in sebaceous cell carcinoma as pagetoid spread may be difficult to identify using this technique because of poor resolution and tissue artifacts of freezing. For this reason, I use a permanent section, evaluated overnight, to determine if margins are clear of tumor. This is somewhat tedious, but gives the best accuracy in terms of tumor removal. The defect is then reconstructed using the usual techniques of repair. Because sebaceous cell carcinoma often involves the upper lid, reconstruction is often complicated.

Sebaceous cell carcinoma is an uncommon tumor. It is difficult to diagnose because of its many manifestations. It is difficult to excise because of pagetoid spread and noncontiguous tumor origins. Unlike with basal cell carcinoma and squamous cell carcinoma, there is a possibility of regional lymph node metastasis (Figure 11-7). In most patients, no regional disease is present at the time of diagnosis. Fortunately, local resection is usually curative. If all four lids are involved or orbital fat is invaded, orbital exenteration is required. Death caused by sebaceous cell carcinoma is possible, but rare.

Figure 11-7 An unusually aggressive sebaceous cell carcinoma. (A) A large mass of tumor is seen in the superior fornix originating from the upper lid tarsus. (B) Regional and “in transit” lymphatic metastases were present. Despite orbital exenteration, neck dissection, and radiation therapy, the patient died a few months after diagnosis.

Benign lesions arising in the sebaceous glands include chalazia, sebaceous hyperplasia, and sebaceous adenoma. These lesions will be discussed later in the chapter.

General concepts

Although eyelid melanomas are rare, we are all concerned about the possibility of a pigmented lesion being a melanoma. This section will help you to differentiate benign from malignant pigmented lesions of the skin. Let’s start with these basic concepts (Box 11-3).

• The majority of pigmented lesions will not be melanoma

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