CONDITION

Meningioma

A meningioma is a growth that arises from the meninges, the protective membranes that surround the brain and spinal cord. In dogs and cats, these growths develop most often around the brain, and although they tend to grow slowly and rarely spread to other parts of the body, they can still cause problems by pressing on nearby brain tissue as they enlarge. Owners most commonly notice changes in behaviour, unexplained seizures that begin in an older animal, subtle shifts in personality, or signs such as unsteadiness, head pressing, or changes in vision. The signs depend on where the growth is located and how much pressure it exerts. Many meningiomas are discovered incidentally during imaging performed for another reason, before any outward signs appear. This page explores what signals may bring a meningioma to attention, what is happening beneath the surface, how these growths are investigated using imaging and sometimes biopsy, and the range of approaches—including monitoring, surgery, and radiation—that may be considered depending on location, size, and the individual animal's circumstances.

Why this matters now

Meningiomas tend to appear in older dogs and cats, most often those beyond eight or nine years of age, though younger animals are occasionally affected. Certain breeds, including Golden Retrievers, Collies and other dolichocephalic (long-nosed) breeds, appear to develop meningiomas more frequently than others — in contrast, brachycephalic breeds such as Boxers are instead predisposed to a different type of brain tumour, glioma, though meningiomas can arise in any breed. In cats, domestic shorthairs are the breed most often diagnosed with meningioma, but this reflects their overall numerical dominance in the pet cat population rather than a true breed predisposition; no genuine breed risk factor has been established in cats. The condition reflects a slow accumulation of changes in the meningeal cells over time rather than a sudden event.

Most meningiomas grow slowly, over months to years, and the signs an owner notices often mirror that gradual pace. Early changes may be subtle enough to blend into the background of normal ageing, becoming more apparent only as the growth occupies more space or compresses structures with less tolerance for pressure. Some meningiomas remain stable in size for extended periods, whilst others progress more steadily, and the rate of change can vary considerably between individual animals.

Signals & patterns

Early signals

Behaviour that seems altered

An owner may notice their dog or cat seems less interested in familiar activities, more withdrawn, or responds differently to household routines. These shifts can be subtle and may initially be mistaken for the effects of ageing, but they often reflect pressure on areas of the brain involved in mood and social engagement.

Seizures beginning in mid-life or later

A first seizure occurring in a dog or cat older than five or six years can signal a structural change in the brain, as seizures in older animals are less commonly due to inherited epilepsy. The pattern, frequency, and features of the seizures can vary widely depending on which part of the brain is affected.

Subtle loss of coordination

An animal may begin to misjudge jumps, drift slightly to one side when walking, or move with less precision than usual. These changes tend to develop gradually and may be more noticeable on stairs, uneven ground, or when turning.

Changes in vision or tracking

Some owners observe their pet bumping into objects on one side, hesitating before moving through doorways, or responding less reliably to visual cues such as a thrown toy. This can occur when a meningioma compresses pathways involved in processing what the eyes see.

Unusual head posture or tilt

A persistent tilt or turn of the head to one side, or a reluctance to raise or lower the head normally, may reflect pressure on structures that help the brain interpret balance and spatial orientation.

Later signals

More frequent or prolonged seizures

Seizures may increase in frequency, last longer, or become more difficult to interrupt as the growth continues to compress surrounding brain tissue. Some animals experience clusters of seizures over a short period.

Marked difficulty with movement

Coordination may deteriorate to the point where walking becomes unsteady, circling becomes pronounced, or the animal struggles to rise or navigate familiar spaces. This reflects increasing pressure on motor and balance centres within the brain.

Changes in consciousness or responsiveness

An animal may seem less aware of its surroundings, slow to respond to its name, or appear to stare vacantly. Episodes of confusion, disorientation, or altered wakefulness can occur when deeper brain structures are affected by pressure or swelling.

Click to read about the biological mechanisms

How this is usually investigated

Investigation usually begins with a detailed history of the changes an owner has observed, their pace, and any patterns, alongside a thorough neurological examination to map which parts of the nervous system may be affected. Blood tests can help rule out metabolic causes of similar signs, though they do not confirm or exclude a meningioma. When the history and examination point towards a problem within the skull, imaging of the brain becomes the central part of the investigation.

Physical examination

Purpose: A neurological examination assesses gait, posture, cranial nerve function, reflexes, and conscious responses to stimuli, helping to localise which part of the brain may be under pressure.
Considerations: The examination can suggest a problem within the skull and narrow the region involved, but it cannot identify the nature of the mass or distinguish a meningioma from other intracranial growths.

Chemistry panel

Purpose: Blood chemistry helps identify metabolic conditions such as liver or kidney disease, electrolyte disturbances, or low blood glucose that can produce neurological signs similar to those caused by a brain mass.
Considerations: Results are typically normal in animals with meningioma, so the purpose is mainly to exclude other causes rather than to confirm the presence of a growth.

Magnetic resonance imaging (MRI)

Purpose: MRI provides detailed images of the brain's soft tissue structures and can reveal the location, size, shape, and relationship of a mass to surrounding tissue, as well as any associated swelling or fluid changes. It is the imaging method that offers the clearest view of meningiomas and their effects on adjacent brain.
Considerations: MRI requires general anaesthesia and access to specialist imaging facilities, and whilst it can strongly suggest a meningioma based on appearance and location, definitive identification of the cell type requires tissue sampling.

Computed tomography (CT)

Purpose: CT imaging can identify masses within the skull, show their size and position, and reveal any changes to the bone where the growth attaches. It can also detect calcification within the mass, which is common in meningiomas.
Considerations: CT is often more widely available and faster than MRI, though it provides less detail of the soft tissue structure of the brain itself. It can be particularly useful when planning surgical removal, as it shows the relationship between the mass and the skull.

Histopathology

Purpose: Microscopic examination of tissue removed during surgery, or occasionally obtained by biopsy, confirms the cell type and can identify features that suggest how the growth may behave over time.
Considerations: Histopathology provides the definitive diagnosis, but it requires either surgical removal of the mass or a separate biopsy procedure, both of which carry their own risks and are not always practical or chosen.

Options & trade-offs

Management of a meningioma can involve surgical removal, radiation therapy, medication to manage the effects of the growth, or a combination of these approaches. The choice depends on the location and size of the mass, the severity of signs, the animal's overall health, and what feels workable to the owner. Different animals and different owners find different combinations practical, and the path often evolves over time as the situation changes.

Surgical removal

Surgery aims to remove as much of the meningioma as can safely be reached, often via an opening in the skull called a craniotomy. Many meningiomas sit on the surface of the brain with a clear boundary, which can make them easier to separate from surrounding tissue than growths that invade the brain itself. The procedure is performed by specialist surgeons and requires careful post-operative monitoring.

Trade-offs: Surgery can produce rapid improvement in signs when a significant portion of the mass is removed, particularly for growths that are well-defined and accessible. It carries risks associated with brain surgery, including bleeding, swelling, infection, and effects specific to the part of the brain involved, and complete removal is not always possible depending on location and attachment.

Radiation therapy

Radiation targets the meningioma with focused beams that damage the DNA of dividing cells, slowing or stopping growth over time. It is often used when surgery is not practical due to the location of the mass, when only partial removal was possible, or when an owner prefers a non-surgical approach. Treatment typically involves multiple sessions spread over several weeks.

Trade-offs: Radiation does not remove the mass but can control its growth and relieve pressure over time, with many animals experiencing improvement or stabilisation of signs for months to years. It requires repeated anaesthesia and access to specialist centres, and effects on surrounding brain tissue can occasionally produce delayed changes months or years after treatment.

Medical management of seizures and swelling

Anti-seizure medication can reduce the frequency and severity of seizures caused by pressure or irritation from the meningioma, whilst corticosteroids such as prednisolone can reduce swelling in the brain tissue surrounding the mass. These medications address the effects of the growth rather than the growth itself.

Trade-offs: Medical management can improve quality of life and is often used alongside other approaches or when surgery and radiation are not chosen. It does not alter the size or progression of the meningioma, so signs may eventually worsen as the mass continues to grow, and long-term corticosteroid use carries its own side effects.

Monitoring without intervention

Some meningiomas grow very slowly or produce mild signs that do not significantly affect an animal's day-to-day life, and in these cases an owner may choose to monitor the situation with periodic reassessment rather than pursue treatment. This approach can involve repeat imaging over time to observe the rate of change.

Trade-offs: Monitoring allows time to observe how the meningioma behaves in an individual animal and can be appropriate when signs are minimal or when the risks of treatment feel disproportionate. It does not prevent progression, and signs may gradually worsen, at which point treatment options can be reconsidered if the situation changes.

Common misconceptions

Misconception:

"A meningioma diagnosis means the animal has only a short time left."

Reality:

Many meningiomas grow slowly, and both surgical removal and radiation therapy can produce long periods of good quality of life, often measured in years rather than months. The outlook depends heavily on the location, size, and individual behaviour of the growth, as well as the treatment chosen, and some animals live for several years after diagnosis with intervention.

Misconception:

"Brain surgery in animals is too risky to consider."

Reality:

Whilst surgery within the skull carries inherent risks, specialist centres with experience in cranial procedures report success rates and survival times that can make surgery a reasonable option for many meningiomas, particularly those that are accessible and well-defined. The risks and benefits vary depending on the individual case, and the decision involves weighing the current and expected quality of life against the risks specific to that animal and that mass.

Misconception:

"If the meningioma cannot be completely removed, there is no point in surgery."

Reality:

Partial removal of a meningioma can still relieve pressure, reduce signs, and improve quality of life, even when the entire mass cannot be safely taken out. Radiation therapy can then be used to control what remains, and many animals benefit from this combined approach even when complete removal is not possible.

Related conditions

Brain Tumours

Meningioma is one type of brain tumour, arising specifically from the meninges rather than from brain tissue itself. The broader brain tumours page explores the full range of growths that can occur within the skull, including those that arise from different cell types and locations.

Glioma in Dogs

Gliomas arise from within the substance of the brain itself, whilst meningiomas grow from the membranes on its surface. Both can cause similar outward signs—seizures, behavioural changes, or unsteadiness—depending on their location, but their origin, imaging appearance, and surgical accessibility often differ.

Pituitary Macroadenoma

A pituitary macroadenoma is a growth at the base of the brain that can press on surrounding structures, sometimes producing neurological signs that overlap with those of meningioma. Both are typically slow-growing and may be discovered during imaging performed for seizures, behavioural changes, or other signs, though their hormonal and anatomical contexts differ.

Granulomatous Meningoencephalomyelitis (GME)

Granulomatous meningoencephalomyelitis is an inflammatory condition affecting the brain and meninges, and it can produce signs—such as seizures, altered behaviour, or focal neurological deficits—that may resemble those caused by a meningioma. Advanced imaging and sometimes biopsy are used to distinguish inflammation from a structural growth.

Epilepsy in Cats

Seizures are a common presentation of meningioma, particularly when the growth presses on areas of the brain involved in electrical activity. Epilepsy in cats encompasses all causes of recurring seizures, and a meningioma is one structural cause that may be identified during investigation of new-onset seizures in an older animal.

Meningiomas sit within a broader group of conditions that can produce neurological changes in older animals, including other types of brain growths, inflammatory diseases of the central nervous system, and gradual degenerative changes. Understanding the possible range can help an owner make sense of what they are observing and what questions might be useful to explore over time. The Longevity & Healthspan pillar offers context on the patterns that tend to emerge as animals age and how those patterns intersect with individual variation.