Simple cysts of eccrine or apocrine sweat glands are called eccrine hidrocystoma or apocrine hidrocystoma, respectively (see Chapter 11). Herein, we discuss solid tumors derived from sweat gland epithelium, beginning with syringoma.

Syringoma is a common benign tumor of eccrine sweat gland origin (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19). About 20% develop on the eyelids (6). It occurs more often in young adult women and has a slight predilection for Asians (10).

Syringoma can be solitary or multiple. The multiple variant is more common and is often bilateral, symmetric, and most pronounced on the lower eyelid. They are often subtle and hardly noticed by the patient. Multiple syringomas each range from 1 to 3 mm in size and have a yellow-brown color (3,7). Multiple syringomas are usually not associated with other conditions. However, some reports indicate that it is more common in patients with Down’s syndrome (4,11,12), Marfan’s syndrome, and Ehlers-Danlos syndrome (7,12).

Differential diagnosis includes most of the eyelid lesions discussed in this atlas. Solitary lesions can simulate basal cell carcinoma, sebaceous adenoma, and sebaceous carcinoma. The multiple variety can simulate trichoepithelioma, milium, sarcoidosis, and other conditions (2).

Based on histochemical and electron microscopic findings, syringoma represents an adenoma of eccrine ducts (1,3,5). It is composed of cords and nests of solid cells with ducts located within a dense fibrous tissue stroma. The ducts are lined by a double layer of compressed epithelial cells that sometimes assume a comma-shaped or “tadpole” appearance, a feature considered characteristic of this condition (3,7). Numerous cystic dilations of the ducts can result in keratin cysts that can suggest the diagnosis of milium, trichoepithelioma, or squamous cell carcinoma. The keratin cysts can rupture and incite a granulomatous inflammatory reaction (3). Concerning pathogenesis, human papillomavirus types have been detected in solitary eyelid syringoma, suggesting a viral etiology (13).

Management is usually observation. Cosmetics can improve appearance. A larger solitary lesion may require surgical excision to rule out malignancy. Other methods of management include electrodessication and curettage, dermabrasion, and carbon dioxide laser resurfacing (14,15,16,17,18,19). Some authors have advocated combination of carbon dioxide laser and trichloroacetic acid (16). Although solitary syringoma is cytologically benign, it can recur after incomplete excision and exhibit aggressive behavior.

Syringoma can be multiple or solitary. Although syringoma is almost always benign, low-grade malignant behavior can rarely occur.

Eccrine acrospiroma (also called clear cell hydradenoma, eccrine hydradenoma, and porosyringoma) is a tumor that arises from duct and secretory coil of the eccrine sweat gland (1,2,3,4,5,6,7,8,9,10,11,12,13). It is usually solitary and can occur in all parts of the body, with the face and ears being affected in about 10% of cases (1). It can be nodular, solid, or cystic. Although the majority are benign, a malignant variant has been observed (1). The terminology regarding this lesion has been the source of some confusion, but “eccrine acrospiroma” seems to be preferred.

Eccrine acrospiroma of the eyelid can assume any of a variety of clinical patterns. It is generally a rather rapidly growing solid or cystic lesion that may attain a size of 5 to 30 mm. A smaller lesion may be similar in color to the normal adjacent skin or it may appear as a fleshy subcutaneous mass. A larger eccrine acrospiroma often has blue, crusty appearance and may sometimes become ulcerated. Pain on pressure can be elicited in about 20% of cases (7). The tumor can occasionally show aggressive growth and invade the conjunctiva and orbit (9,11).

Histopathologically, eccrine acrospiroma has characteristic features. It is a well-circumscribed lesion deep to the epidermis composed of lobules of epithelial cells that demonstrate a biphasic pattern. One pattern is composed of foci of round to ovoid cells with clear cytoplasm that contain glycogen. The other is composed of closely compact spindle-shaped cells with eosinophilic cytoplasm (1,2,8). In some areas, tumor cells merge with the overlying acanthotic epithelium (8). Enzyme histochemical and electron microscopic studies have established its eccrine gland origin (1,8). Eyelid eccrine acrospiroma has been shown to exhibit oncocytic, apocrine, and sebaceous differentiation, attesting the pluripotentiality of adnexal glandular epithelia (13). Eccrine poroma, a similar tumor that arises from sweat duct epithelium, has been reported on the eyelid (10).

Management is complete surgical excision. The diagnosis is not usually suspected clinically and is made on histopathologic evaluation. The prognosis is excellent.

Unlike a simple eccrine hidrocystoma, eccrine acrospiroma is a solid tumor clinically, although it can sometimes have a cystic component. It can assume a variety of clinical configurations.

Syringocystadenoma papilliferum is an uncommon benign tumor that arises from apocrine glands (1,2,3,4,5,6,7,8,9). It occurs most often on the scalp and temple and only occasionally on the eyelid, where it presumably arises from the apocrine glands of Moll. In one series, it accounted for 2% of ocular adnexal tumors of apocrine, eccrine, or hair follicle origin (9). In about 75% of cases, it arises during puberty within a nevus sebaceous of Jadassohn; thus, it may be a component of the organoid nevus syndrome (10). When it is confined to the eyelid, it is often a solitary lesion that appears in middle age and is not usually associated with nevus sebaceous of Jadassohn (3). It is believed by some authors that syringocystadenoma papilliferum can evolve into basal cell carcinoma and that it may represent a transition phase between nevus sebaceous of Jadassohn and basal cell carcinoma (8).