Your hardworking eccrine sweat glands may be the site of something more sinister -- especially if a syringoid eccrine carcinoma is beginning to multiply within them. This type of cancer cell prefers sweat glands; these cells take hold beneath the skin's surface, hidden within the subcutaneous eccrine gland's coiled structure. You may not realize you have an eccrine tumor in the works right away; it often takes years for a tumor of this type to grow to a noticeable size. There have only been a few cases in which the tumor reached the size of a penny in a few months' time. And, once you develop a syringoid eccrine carcinoma -- even if it's treated successfully -- it's likely to reoccur. Probably in the same place, too [source: Wong].
The good news, however, is that these tumors are exceedingly rare. In fact, fewer than a thousand cases have been reported worldwide. This is one of the reasons data is in short supply, especially when it comes to uncovering the causes of syringoid eccrine carcinoma. There's some speculation that ultraviolet radiation is to blame, which may be worrisome to those who work outdoors or prefer a year-round suntan.
This particular type of cancer may also be common in people with a history of radiation therapy; it's more prevalent near the physical sites of any targeted radiation. While immunosuppressant therapy seems to put people at increased risk for developing syringoid eccrine carcinoma, ironically it's sometimes used to treat syringoid eccrine carcinomas. The majority of these cancers, however, don't spread and can be excised surgically [source: Wong].