Spiradenocarcinoma, from the CureRays guide library.

Spiradenocarcinoma is a rare sweat-gland skin cancer that usually develops inside a long-standing benign skin lump; surgery to remove it completely is the cornerstone, with radiation added for high-risk or spreading tumors.

What it is.

Spiradenocarcinoma is an uncommon cancer that arises from a sweat gland in the skin. Most often it begins as a malignant change within a benign sweat-gland tumor called a spiradenoma — a nodule that may have been present and unchanged for many years. The warning sign is when that long-stable bump suddenly grows, becomes painful, changes color, ulcerates, or bleeds. It can appear anywhere on the body. Because it is so rare, there is no large clinical trial defining the best treatment, so care follows the principles used for other aggressive skin adnexal cancers: completely remove the tumor with clean margins, examine it under the microscope to judge its aggressiveness, and add radiation when the risk of local return or nodal spread is high. While many are controlled by surgery, spiradenocarcinoma can behave aggressively, recurring locally or spreading to lymph nodes and beyond, so careful long-term follow-up is essential.

How radiation treats it.

Radiation damages the DNA inside cancer cells so they can no longer divide. For a skin cancer like spiradenocarcinoma, radiation is usually given after surgery to destroy any microscopic cells that may remain at the edges of the removal or in nearby lymph nodes, lowering the chance the cancer returns. Modern machines shape the beam — using electrons for shallow skin targets or x-rays for deeper ones — so the dose concentrates on the at-risk area while sparing surrounding healthy tissue. Treatment is painless, given as a series of short daily sessions, and leaves no radioactivity in your body.

The ways we can treat it.

Adjuvant external-beam radiation. After surgery, shaped x-ray or electron beams treat the tumor bed and, when needed, the draining lymph nodes, mopping up any microscopic cells left behind to reduce local recurrence.

Definitive radiation when surgery isn't possible. If a tumor can't be removed because of its size or location, radiation can be used as the main treatment to control it, delivered over a series of daily sessions.

Questions we hear often.

I've had a bump for years that just started changing — could this be it? A long-standing skin nodule that suddenly grows, hurts, ulcerates, or bleeds should be checked promptly, because spiradenocarcinoma often arises from a benign sweat-gland lump that has been stable for a long time. A biopsy can tell what's going on.

Will surgery cure it? Complete surgical removal with clean margins offers the best chance of cure, especially for localized, lower-grade tumors. Higher-grade tumors or those that have reached lymph nodes need additional treatment and closer follow-up.

Why might I need radiation if the tumor was removed? Radiation after surgery targets any microscopic cancer cells that may remain at the edges of the removal or in nearby lymph nodes. It's added when the tumor is high-grade, the margins are close, or nodes are involved, to lower the risk of the cancer coming back.

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