Sebaceous carcinoma: a rare skin cancer

Sebaceous glands are the small glands that produce the skin's natural oils, and they are found all over the body, including in the eyelids. Cancer Research UK says sebaceous gland carcinoma is a very rare skin cancer that starts in these glands, and can develop anywhere, although the head and neck is the commonest site. NHS Greater Glasgow and Clyde calls it a rare and aggressive type of skin cancer.

The word aggressive refers to its potential to spread if not found and treated, not to every case. Outcomes depend on the stage, the site and how quickly it is diagnosed, which is why your specialist team is the best source for your individual outlook.

Cancer Research UK lists a genetic condition called Muir-Torre syndrome, a weakened immune system (for example after an organ transplant), ultraviolet radiation from high sun exposure and tanning beds, and older age as factors that can increase risk. Having a risk factor does not mean that you will develop this cancer.

NHS Greater Glasgow and Clyde adds benign adenomas of the skin, earlier radiation such as radiotherapy to the face, and Asian ethnicity to its list of risks for eyelid disease.

Cancer Research UK says sebaceous gland carcinoma usually appears as a firm, painless lump that can be yellowish. On the eyelid it may gradually increase in size and cause irritation to the eye, according to NHS Greater Glasgow and Clyde. Away from the eye, it can occur on the head or neck, the trunk, the arms and legs or the genital area.

The Scottish ocular oncology service warns that it can be tricky to diagnose because it is often mistaken for a chalazion or blepharitis. Because a delayed diagnosis matters, an eyelid lump that persists or keeps coming back deserves a specialist opinion rather than repeated watching.

• A firm, painless lump, sometimes yellow, on or in the eyelid.

• An eyelid lump that grows, keeps returning after treatment, or irritates the eye.

• A firm lump on the scalp, face, trunk or limbs that is slowly increasing.

Cancer Research UK says your GP should arrange for you to see a skin specialist if they suspect a sebaceous gland carcinoma. The main test is a biopsy, usually under local anaesthetic, in which a sample is examined under a microscope. The doctor will also check the rest of your skin and your lymph nodes.

Further tests may be needed to see whether it has spread: a chest X-ray, ultrasound, lymph node tests, CT or PET-CT, or an MRI scan. For eyelid disease, the Scottish ocular oncology service says it takes a photograph and a biopsy, and may arrange chest X-ray, CT or MRI scans if it suspects spread behind the eye or elsewhere.

Cancer Research UK says treatment should be at a specialist skin cancer centre because this is a rare type, where a multidisciplinary team including a dermatologist, plastic surgeon and clinical oncologist discusses the plan. Surgery is the main treatment, aiming to remove all the cancer and a margin of healthy tissue. Options include Mohs micrographic surgery, wide local excision and, sometimes, removal of lymph nodes.

Radiotherapy may be used after surgery or alone if surgery is not possible, usually once a day Monday to Friday and lasting up to 7 weeks. Adjuvant treatment such as chemotherapy cream or cryotherapy is not common. After eyelid surgery, the eyelid is reconstructed to look and work as normally as possible, possibly in a separate operation. Very rarely, a larger operation to remove the eye is needed to clear the cancer.

Cancer Research UK says follow-up appointments are usually at least every 6 months for the first 3 years, then yearly, and that scans may be used. The Scottish ocular oncology service says the tumour can grow back after treatment, and that spread, if diagnosis is delayed, can occur in up to a quarter of patients, mentioning also a figure of around 1 in 5 for spread in another section of its page.

Those figures describe groups of patients and cannot predict one person's course. Cancer Research UK advises that your doctor is the best person to talk to about your outlook, and that not everyone wants to know.