Tumefactive MS: what it is, how it is diagnosed and treated

The NHS describes multiple sclerosis (MS) as a condition that affects the brain and spinal cord, in which the immune system attacks the brain and nerves. Most people with MS have multiple small lesions seen on MRI. Tumefactive MS is different in how it looks: one large, space-occupying lesion, usually over 2 cm, with a surrounding rim of swelling.

The word tumefactive simply means tumour-like. It does not mean cancer. The lesion is an area of inflammation and loss of myelin (the protective coating of nerve fibres), but because it can push on surrounding tissue and appear mass-like, it can resemble a brain tumour or abscess on a scan.

The Cureus review notes that the cause remains unknown and that, although it is categorised as a subset of MS, it can behave differently from traditional MS. Some people have a tumefactive lesion as their first ever MS event; others develop one after years of typical MS.

The symptoms depend on where the lesion is, so they can vary widely. The Cureus review says the frontal and temporal lobes are most commonly affected, and that motor, sensory, cognitive and cerebellar symptoms predominate. Marked swelling can raise pressure inside the skull, causing headaches and, rarely, a dangerous shift of brain tissue that needs prompt treatment.

In the case it describes, a 25-year-old woman was referred by her ophthalmologist because of a visual field loss, and later developed numbness and tingling on one side. This illustrates how a sudden problem with vision, strength or sensation can be the first sign.

• Weakness, clumsiness or poor coordination.

• Numbness or tingling on one side of the body.

• Changes to vision, including loss of part of the visual field.

• Problems with memory, concentration or thinking.

• Headache from raised pressure, in severe cases.

The NHS advises calling 999 or going to A&E if you have sudden weakness or numbness in one arm, loss or blurring of vision, or problems with balance and co-ordination, because these could be signs of a stroke and need urgent attention. Do not drive yourself to A&E. Symptoms that are milder or have developed over days should be raised with a GP promptly, who can arrange referral to a neurologist.

The NHS says there is no single test to diagnose MS, and that tests may include neurological examination, blood tests, an MRI scan, a lumbar puncture and tests that measure how quickly messages from the eyes or ears reach the brain. For a tumefactive lesion, the key is to distinguish it from a tumour, infection or other cause.

According to the Cureus review, the work-up should include MRI of the brain and spinal cord. Features such as incomplete ring enhancement, more than one lesion and the absence of mass effect are more characteristic of tumefactive MS. A lumbar puncture may reveal oligoclonal bands and myelin basic protein in up to 74% of patients. Brain biopsy is reserved for patients in whom a conservative approach fails.

Because the diagnosis is difficult, it is usually made by a neurology team working with neuroradiology, and sometimes neurosurgery and neuropathology. It is reasonable to ask for a second opinion at a specialist neuroscience centre if you are unsure.

The review states that high-dose corticosteroids are considered first-line treatment, with approximately 86% of patients improving. Where there is no improvement, plasmapheresis (plasma exchange) is considered second-line, and cyclophosphamide has been referenced as potentially effective in cases refractory to both. It also says that the role of long-term disease-modifying therapies is unclear, that interferon beta and glatiramer acetate are preferred and usually started after a second clinical attack, and that fingolimod and natalizumab have been associated with increased tumefactive demyelination and should be avoided.

The NHS notes that general MS care involves a team that may include an MS nurse, neurologist, physiotherapist and occupational therapist, and that treatments include steroids to reduce swelling and help nerves work better, disease-modifying therapies and medicines for symptoms. Rehabilitation and symptom support are therefore a central part of recovery.

The review says the long-term prognosis is variable and that early recognition and appropriate management are paramount in improving outcomes. Roughly one-third of patients do not develop a subsequent attack. For those who do, two-thirds follow a relapsing-remitting course, which the NHS describes as flare-ups followed by remission.

The NHS adds that MS treatments are improving and that most people with MS live into old age. The MS Society and MS Trust, both named on the NHS page, offer information and support, and so does MS-UK. Because tumefactive MS is rare, it is worth asking your neurology team how it was classified and what follow-up scanning is planned.