Eccrine Carcinoma (Sweat Gland Carcinoma), from the CureRays guide library.

Eccrine carcinoma is a rare group of skin cancers that arise from sweat glands, usually appearing as a slowly growing lump on the head, neck, or limbs; treatment centers on complete surgical removal, with radiation used to control microscopic disease — especially for tumors, like microcystic adnexal carcinoma, that creep along nerves.

What it is.

Eccrine carcinoma is an umbrella term for a rare group of skin cancers that develop from the eccrine sweat glands — the glands distributed across the skin that produce sweat to cool the body. Because the sweat gland has several parts, this group includes a number of distinct subtypes that behave differently, ranging from slow-growing and locally troublesome to more aggressive forms that can spread. They typically appear in middle-aged and older adults as a firm bump, nodule, or plaque on the head and neck, the scalp, the limbs, or the trunk, often growing slowly over months to years so that they are easy to mistake for a harmless skin growth. Several subtypes share a tendency to invade locally and deeply and to creep along the sheaths of nerves (perineural invasion), which means the cancer can extend well beyond what is visible and is prone to coming back if not treated widely enough. Some subtypes can also spread to nearby lymph nodes and, less often, to distant organs. Because these cancers are uncommon and varied, accurate diagnosis by an expert skin pathologist is essential — both to confirm that a tumor is an eccrine carcinoma rather than a benign sweat-gland growth or a cancer that has spread to the skin from elsewhere, and to identify the specific subtype, which guides treatment. The cornerstone of care is surgery to remove the tumor completely with a clear margin, frequently using margin-controlled (Mohs) techniques; radiation is an important partner, used to treat the microscopic disease these tumors leave behind, particularly along nerves, and as the main treatment when surgery isn't possible.

How radiation treats it.

Radiation therapy treats eccrine carcinoma by delivering focused beams of energy that damage the DNA inside tumor cells so they can no longer grow and divide. Its role is shaped by a behavior several of these sweat-gland cancers share: rather than staying within the visible bump, they invade deeply and, in some subtypes, creep along the sheaths of nerves, leaving microscopic disease that extends well beyond what can be seen or felt. If only the obvious tumor were removed, those extensions — especially along nerves — could be left behind and seed a recurrence, which is why these cancers are prone to coming back if not treated widely enough. Radiation treats a wider zone, and for the nerve-tracking subtypes the field is deliberately extended to follow the course of the involved nerves, sterilizing microscopic disease that surgery cannot reach. This is the main reason radiation is so often paired with surgery here. It is given after surgery for tumors that invade deeply, track along nerves, or could not be removed with a comfortable clear margin, and it is also directed at the lymph nodes — after they are removed, or when they are involved — because the draining nodes are the first place these cancers tend to spread. When surgery is not a good option, focused radiation can serve as the main treatment, controlling the tumor and relieving symptoms. Because these cancers arise in the skin, radiation can often be delivered with techniques suited to surface targets, such as low-energy X-rays or electron beams, which concentrate the dose in the skin and the tissue just beneath while sparing deeper structures; for deeper or nerve-tracking disease, more penetrating, precisely shaped beams are used. Throughout, modern planning shapes the dose to cover the tumor, its bed, or the nerve pathway while limiting exposure to surrounding normal tissue, balancing effective treatment with a good cosmetic and functional result.

The ways we can treat it.

Postoperative (adjuvant) radiation. Radiation to the tumor bed after surgery sterilizes microscopic disease left behind, lowering the chance of recurrence for deeply invasive or nerve-tracking tumors or when margins are close.

Radiation along nerve pathways. For subtypes that creep along nerves, the radiation field is extended to follow the involved nerves' course, treating microscopic disease that surgery cannot see — a key reason radiation is paired with surgery in these cancers.

Nodal radiation. Radiation to the lymph node region after node surgery, or when nodes are involved, treats microscopic disease there and lowers the chance of regional recurrence.

Superficial / electron-beam radiation. For tumors confined to the skin, low-energy X-rays or electron beams concentrate dose at the skin surface while sparing deeper tissue, an efficient way to treat the target.

Questions we hear often.

What does 'eccrine carcinoma' actually mean? It's an umbrella term for a rare group of skin cancers that begin in the eccrine sweat glands — the glands all over the skin that make sweat to cool the body. Because the sweat gland has several parts, this group includes a number of distinct subtypes that behave differently, from slow-growing tumors that mainly cause local trouble to more aggressive ones that can spread. That variety is why identifying the exact subtype is so important: it tells your team how aggressively the cancer is likely to behave, how widely to treat, and where to look for any spread. Some specific subtypes — such as microcystic adnexal carcinoma and porocarcinoma — are common enough to have their own detailed guides.

Why might radiation be aimed along a nerve? Several sweat-gland cancers have a habit of creeping along the sheaths of nerves, a pattern called perineural invasion. This lets microscopic cancer extend well beyond the visible tumor, following a nerve's path in a way that surgery can't fully see or remove. When the pathologist finds this, the radiation field is deliberately extended to follow the course of the involved nerve, treating the microscopic disease traveling along it. This is one of the main reasons radiation is paired with surgery for these tumors — it targets exactly the hidden extensions that would otherwise cause the cancer to come back.

Will surgery alone cure it? Often yes, especially for thin, slow-growing tumors with no high-risk features, which are usually cured by complete removal with a clear margin and then followed with skin checks. But because several subtypes invade deeply, track along nerves, or can reach the lymph nodes, additional treatment is added when the removed tumor shows those features or when the margin is close. In those cases radiation lowers the chance of the cancer returning, and the lymph nodes may be evaluated. The right plan depends on the specific subtype and what the pathology shows, which is why expert diagnosis is such an important first step.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.