Thyroid lymphoma: symptoms, diagnosis and treatment in the UK

The British Thyroid Foundation explains that lymphomas are cancers that come from lymphocytes, the cells in the body that fight infection and are found mainly in the blood and lymph nodes. Thyroid lymphoma is a lymphoma that arises in the thyroid gland, the butterfly-shaped gland at the front of the neck that makes thyroid hormone.

It is different from the more familiar thyroid cancers that start in thyroid cells themselves, because the cancer cells are lymphocytes. The NHS describes non-Hodgkin lymphoma as cancer that affects the white blood cells that help you fight infection, and the British Thyroid Foundation says most thyroid lymphomas are non-Hodgkin B-cell lymphomas.

The main types it lists are diffuse large B cell lymphoma (with or without a marginal zone component), marginal zone B cell lymphoma of mucosa-associated lymphoid tissue, known as MALT lymphoma, and follicular lymphoma. Which type you have affects how fast it is likely to grow and how it is treated.

The British Thyroid Foundation says thyroid lymphoma usually occurs within a thyroid gland that already has an autoimmune disease, for example autoimmune thyroiditis, also called Hashimoto's thyroiditis, with thyroid peroxidase (TPO) autoantibodies in the blood. Thyroid lymphoma is described as rare.

For non-Hodgkin lymphoma in general, the NHS says it is not known what causes it, but you may be at higher risk if you are over 50, have had certain infections including Epstein-Barr virus and hepatitis C, have a weakened immune system, have an autoimmune condition such as coeliac disease or psoriasis, or have a close relative who has had non-Hodgkin lymphoma. These are general risk factors for the wider group of lymphomas rather than a checklist for the thyroid.

The British Thyroid Foundation says thyroid lymphoma usually presents in one of three ways: an enlarging nodule in the thyroid, enlargement of the whole thyroid gland, or a swollen lymph node in the neck. It adds that these changes may appear slowly in some people and grow rapidly in others.

The NHS lists general symptoms of non-Hodgkin lymphoma that can occur with any lymphoma: a painless lump or swelling, usually in the neck, armpit or groin, which it calls the most common symptom; a high temperature or feeling hot, cold or shivery; night sweats; shortness of breath; itchy skin; and sudden unexplained weight loss. The NHS stresses that many of these symptoms are common and have many causes, and advises seeing a GP if you think you might have symptoms of non-Hodgkin lymphoma.

A new or growing swelling in the neck is a reason to see a GP. The GP will ask about symptoms, may feel for lumps in the neck, armpit and groin, and may arrange a blood test. They may refer you urgently to a specialist if they think symptoms could be cancer, which the NHS says does not definitely mean you have cancer.

For the diagnosis to be made, the British Thyroid Foundation says a biopsy needs to be taken. This may be done with a fine needle aspiration, where cells are removed from a thyroid nodule using a thin needle and examined under a microscope. It adds that most lymphomas need more than just a fine needle aspiration to make a diagnosis, so a core biopsy, which takes a larger piece of tissue, is usually preferred.

The British Thyroid Foundation says a whole-body PET scan, which combines a radioactive injection with a CT scan, is likely to be used to understand the true extent of the tumour. For non-Hodgkin lymphoma generally, the NHS says the main test is a biopsy of the affected lymph node or tissue, that biopsy results should usually be available within 2 weeks, and that further tests may include blood tests, scans such as PET, CT, MRI or ultrasound, and sometimes a bone marrow biopsy to show how far the lymphoma has spread, known as staging.

You will also be told what type of lymphoma you have and whether it is slow-growing (low grade) or fast-growing (high grade). The stage, grade and type together guide treatment. The British Thyroid Foundation notes that each person is considered individually, so different thyroid lymphomas may be investigated and treated differently.

The British Thyroid Foundation says almost all thyroid lymphomas are treated with specific chemotherapy and/or radiotherapy regimens. In rare cases a MALT lymphoma is present only in a nodule in the thyroid and can be treated with surgery, either removal of half the thyroid (hemithyroidectomy) or the whole thyroid (total thyroidectomy). If the lymphoma is in lymph nodes, surgery is not usually advised, other than for diagnostic or biopsy reasons, and radiotherapy and chemotherapy are likely to be used.

It also says your doctor should involve a specialist haematology oncologist as soon as possible, and that your case should be considered at a cancer multidisciplinary meeting so the right diagnostic and treatment plan is made.

For non-Hodgkin lymphoma in general the NHS says treatment depends on whether it is fast growing or slow growing, where it is in the body, the type, whether it has spread, your symptoms and your general health. Fast-growing lymphoma needs to be treated straight away and can often be cleared completely, although sometimes further treatment is needed. Slow-growing lymphoma is not usually cured but can be kept under control for many years, and treatment can sometimes be delayed if you have no symptoms, an approach called watch and wait.

The British Thyroid Foundation says follow-up will usually be undertaken by a specialist haematology oncologist and their nursing team. It adds that some of the treatments may affect how well the thyroid works, so thyroid function should be monitored and thyroid hormone replacement with levothyroxine started as required.

The NHS says treatment for non-Hodgkin lymphoma can sometimes affect the ability to have children, and that anyone who wants children in the future should speak to the specialist team before treatment starts.

A rare condition like thyroid lymphoma is usually managed through an NHS cancer pathway that brings together endocrinology, haematology, pathology, imaging and oncology in a multidisciplinary meeting. Private consultations and scans are an option for some people and can sit alongside this, but the treatment plan still depends on the same pathology and staging information. Ask for copies of biopsy and scan reports so any second opinion is based on the full picture.