The syringoma, a benign sweat duct tumor, belongs to the classification of skin neoplasms known as the "skin appendage tumors"--thus called because they display certain structural similarities to the hair follicle, the sebaceous gland, the epidermis, the apocrine gland, or the eccrine gland. Due to its line of differentiation, the syringoma is categorized as an eccrine appendage tumor (along with the eccrine nevus, hydrocystomas, spiradenomas, and others). Occurring more often in females than males, syringomas may develop at any age, but appear most often in the early teen years and progressively become more numerous throughout life. Their areas of distribution include the axillae, umbilical, and pubic areas, and less commonly the forehead. There are also cases of syringomas in which the lesions are limited to the lower eyelids. Grossly, the lesions appear as skin colored or slightly yellowish firm papules ranging from one to three millimeters in size. And in the eruptive form they arise in successive crops on the anterior truck and abdomen. Histopathologically, the upper and mid-dermis contain numerous small cystic ducts, and solid epithelial strands embedded in a fibrous storm. Under electron microscopy the strands of epithelial cells and outer layers of the ducts are identical to those composing the outer layers of the embryonic eccrine sweat ducts. Further support as to the origin of these tumors is that the tumor cells contain all the eccrine types of enzymes. Many of the less mature tumors, including the syringoma, exhibit marked similarities tot he corresponding embryonic appendages. But this similarity does not conclude that these tumors originate from dormant embryonic tissue, but signifies that they are as equally immature. In accordance with their immature appearance, these tumors also possess the same abilities of the matrix cells of the epidermis and its appendages. Thus, these tumors theoretically possess the lifelong capability to differentiate into any other type of skin appendage and any tumor derived from that particular appendage. At present, it is not known what the specific causes are that initiate the conversion of normal cells into tumor cells. But it does appear that the benign immature skin tumors represent certain stages in the differentiation of certain matrix cells towards their mature counterparts (e.g. eccrine, apocrine, pigmentary hair or sebaceous nevi). Concerning treatment, as stated earlier, the lesions are benign with no malignant potential, and except for cosmetic purposes, no treatment is necessary. But if so desired, they can be easily destroyed by superficial electrocoagulation, laser, epilation, curettage, or excision. The scars may not be worth the effort to remove the syringomas.