Cerebral Cavernous Malformation (Cavernoma)

Our Specialists for Cerebral Cavernous Malformation (Cavernoma)

UChicago Medicine is a designated Cavernous Malformation Center of Excellence — one of only a handful in the country recognized by the Alliance to Cure Cavernous Malformation. Our team sees more of these lesions in a year than most neurosurgeons see in a career, and we treat everything from a single incidental lesion to complex familial disease with dozens of cavernomas.

Issam A. Awad, M.D., M.Sc., FACS

Section Chief, Vascular Neurosurgery

Dr. Awad is Section Chief of Vascular Neurosurgery and a world authority on cerebral cavernous malformations. He discovered the Common Hispanic CCM1 and Ashkenazi Jewish CCM2 mutations and leads the nation's first designated CCM Center of Excellence, with continuous NIH funding since 1998. He has authored more than 400 publications with over 100,000 citations, serves as past President of the Congress of Neurological Surgeons, and is an elected member of the Association of American Physicians. Dr. Awad directs UChicago's designated Cavernous Malformation Center of Excellence and is internationally recognized as the world authority on this disease — his lab discovered the Common Hispanic CCM1 founder mutation (New England Journal of Medicine, 1996) and the Ashkenazi Jewish CCM2 founder mutation, and he led the recent AT CASH EPOC randomized trial of atorvastatin for rebleeding (Lancet Neurology, 2025). If you have a cavernous malformation — sporadic or familial, supratentorial or brainstem — Dr. Awad is the person most patients in the world would want reviewing their case.

Sean P. Polster, M.D.

Co-Director, Stroke Center; Safadi Faculty Scholar

Dr. Polster is Co-Director of the Stroke Center and directs the Skull Base & Neurovascular Laboratory at UChicago. He leads the Gut-Brain Axis Laboratory, where he was the first to demonstrate that the gut microbiome modulates the effects of radiosurgery on the neurovascular unit. His work is funded at the NIH NINDS R-level, and he has published in Nature Communications, Blood, Stroke, and the Journal of Neurosurgery. Dr. Polster works alongside Dr. Awad in the UChicago CCM program and was a co-investigator on the AT CASH EPOC trial, helping design the imaging and clinical endpoints used to track bleeding on serial MRI (Journal of Neurosurgery, 2019). He operates on cavernomas across the full spectrum — from straightforward lobar lesions in patients with epilepsy to brainstem resections for patients who have bled more than once.

Omer Doron, M.D., Ph.D.

Endovascular Neurosurgeon

Dr. Doron is an endovascular neurosurgeon who brought more than 2,500 endovascular procedures with him from his Harvard/MGH fellowship. He performs both catheter-based and open microsurgical treatment of aneurysms, stroke, and vascular malformations, and he is building out thrombectomy capability across UChicago's regional network. He holds a PhD in biomedical engineering from Hebrew University of Jerusalem. Dr. Doron brings skull-base and cerebrovascular microsurgical expertise to UChicago's CCM program, particularly for the deep and brainstem lesions that require approaches through the posterior fossa and supracerebellar or transpetrosal corridors. For patients whose cavernoma sits in one of the harder-to-reach parts of the brain, he is often part of the surgical plan.

What Is a Cerebral Cavernous Malformation?

A cerebral cavernous malformation (CCM), also called a cavernoma or cavernous angioma, is an abnormal tangle of small blood vessels in the brain or spinal cord. Under a microscope, it looks like a cluster of thin-walled blood-filled sacs pressed together — which is why radiologists often describe it as resembling a mulberry. The vessels inside don't have normal brain tissue between them, and their walls are fragile enough that blood can slowly leak out.

Unlike an arteriovenous malformation (AVM) or an aneurysm, a cavernoma is a low-flow lesion. It doesn't pulse or carry blood under high pressure. That's why cavernomas rarely cause the kind of sudden, catastrophic hemorrhage that people fear when they hear the word "brain bleed." Most bleeds are small, self-contained, and happen gradually.

Cavernomas are common — about 1 in every 200-250 people has one — but most never cause any problem and are only discovered when someone gets an MRI for an unrelated reason like a headache or head injury. Others announce themselves with a seizure, a focal neurological symptom, or a small bleed that shows up as a new headache or weakness.

What Does It Feel Like?

Many people with a cavernoma feel nothing at all. When symptoms do occur, they depend almost entirely on where the lesion sits and whether it has bled. The same-sized cavernoma can be completely silent in one part of the brain and life-changing in another.

If the cavernoma is in the cerebral cortex (surface of the brain)

• Seizures — the most common presenting symptom for cortical cavernomas. They can range from a brief staring spell to a full convulsion.
• Headaches, sometimes triggered by a small bleed
• Weakness, numbness, or speech changes if the lesion is near an eloquent area

If the cavernoma is in the brainstem

• Double vision, crossed eyes, or trouble with eye movements
• Facial numbness or weakness
• Dizziness, vertigo, or trouble with balance
• Difficulty swallowing or slurred speech
• Weakness or numbness on one side of the body

If the cavernoma is in the spinal cord

• A band of numbness or tingling below the lesion
• Weakness in the arms or legs
• Changes in bladder or bowel function

A common story we hear is: "I had a sudden headache, an MRI showed a small bleed, and now they're telling me it's a cavernoma." That's a textbook presentation, and the first question we ask is: where is it, and has it bled before?

How Is It Diagnosed?

The workhorse of cavernoma diagnosis is MRI. On standard MRI sequences, a cavernoma has a distinctive "popcorn" or mulberry appearance, often with a dark rim of old blood products (hemosiderin) around it from prior microbleeds.

The single most important sequence for us is a gradient echo (GRE) or susceptibility-weighted imaging (SWI) scan. These sequences are exquisitely sensitive to tiny amounts of old blood, and they can reveal cavernomas that are invisible on standard MRI. In patients with familial CCM, SWI often shows dozens of lesions where a standard MRI only showed one or two — and that can completely change how we counsel you about risk and monitoring.

A few important points about diagnosis:

• CT scans miss many cavernomas. If your only imaging so far has been a CT, a dedicated brain MRI is the next step.
• Angiograms are usually normal. Because cavernomas are low-flow, they don't show up on a catheter angiogram the way AVMs do. This is sometimes called an "angiographically occult" lesion.
• Genetic testing is considered if you have multiple lesions, a family history of cavernomas or strokes, or Hispanic or Ashkenazi Jewish ancestry with a single lesion — because of the known founder mutations in those populations (more on that below).

At UChicago, we often re-read outside MRIs in our own reading room and add SWI or high-resolution sequences if they weren't done. Getting the imaging right is the difference between watching one small lesion and recognizing a genetic syndrome that needs family screening.

Types of Cavernous Malformation

When we talk about "types" of cavernoma, we're really asking two separate questions: Is it sporadic or familial? and Where in the nervous system is it sitting? Both answers shape your treatment plan.

Sporadic vs. familial

• Sporadic cavernoma — a single, isolated lesion in someone with no family history. This is the most common form, accounting for roughly 70-80% of cases. Sporadic cavernomas are often associated with a nearby developmental venous anomaly (DVA), a normal vein variant that's usually left alone during surgery.
• Familial CCM — an inherited, autosomal dominant condition caused by a mutation in one of three genes: CCM1 (KRIT1), CCM2 (Malcavernin), or CCM3 (PDCD10). Patients with familial disease typically have multiple cavernomas — sometimes dozens — and continue forming new lesions throughout life. Dr. Awad's team at UChicago helped discover the Common Hispanic Mutation in CCM1 (a founder mutation tracing back centuries in Hispanic-American families of Mexican descent) and a founder mutation in CCM2 in the Ashkenazi Jewish population. If you are of Hispanic or Ashkenazi background and you have even one cavernoma, genetic testing is worth considering.
• CCM3 disease deserves special mention — it's the most aggressive form. Patients with CCM3 mutations often present in childhood, develop many lesions, and have a higher rate of early hemorrhage, scoliosis, and associated benign tumors.

Superficial vs. deep

• Superficial (lobar) cavernomas sit in the outer parts of the brain — the frontal, temporal, parietal, or occipital lobes. When symptomatic, these are the most straightforward to remove surgically.
• Deep cavernomas sit in the brainstem, thalamus, or basal ganglia. A brainstem cavernoma is the hardest case we see. Every millimeter of the brainstem controls something critical — breathing, heart rate, eye movement, swallowing, consciousness — so the decision to operate, and the exact approach, has to be weighed extremely carefully. We reserve brainstem surgery for lesions that have clearly bled and that have come to the pial surface, where we can reach them through a safe entry zone.

How Is It Treated?

Watchful waiting for incidental lesions

If your cavernoma was found by accident, has never bled, and isn't causing symptoms, the right answer is usually to leave it alone and watch it. The annual risk of a first symptomatic bleed from a never-bled cavernoma is under 1% per year. That's a lower risk than what you'd accept from many elective surgeries. We'll typically repeat your MRI at 6-12 months, then space the scans out if nothing changes.

Surgery for accessible symptomatic lesions

Surgical removal — a microsurgical resection — is the definitive treatment for a cavernoma that has bled or that is causing disabling seizures. When the lesion is in a reachable, non-eloquent part of the brain, surgery is very safe, usually curative, and often stops the seizures when the cavernoma was the cause.

During the operation, we use neuronavigation (a GPS-like system matched to your MRI), intraoperative ultrasound to locate the lesion through the brain surface, and — for lesions near movement or language areas — electrical brain mapping, sometimes with the patient awake. The goal is complete removal of the cavernoma and the surrounding hemosiderin-stained tissue, which is often where seizures originate.

Surgery for brainstem cavernomas

Brainstem cavernomas are the most technically demanding cases in neurosurgery. We generally recommend surgery only when a brainstem lesion has bled at least once (usually twice), has reached the pial surface of the brainstem, and is causing progressive neurological decline. We use skull-base approaches chosen by the exact location of the lesion, and we rely on intraoperative neurophysiological monitoring — continuously watching the function of the cranial nerves and long motor and sensory pathways while we work.

Radiation — a cautious role

Stereotactic radiosurgery (such as Gamma Knife) is sometimes used for deep cavernomas that can't be safely removed, but it's not a first-line treatment. The evidence that it reduces bleeding is mixed, and it carries its own risk of radiation-induced swelling and new bleeds in the first 1-2 years. We consider it on a case-by-case basis, usually after a multidisciplinary discussion.

Medical therapy and clinical trials

There is no FDA-approved drug yet for cavernoma, but this is an active area of research — much of it led at UChicago. The AT CASH EPOC trial, led by Dr. Awad with Dr. Polster, tested atorvastatin for reducing rebleeding and has informed the next generation of trials targeting the same biological pathway. Patients with familial CCM or with recently bled lesions may be candidates for research studies.

What Are the Outcomes?

The outcome of a cavernoma depends on three things: whether it has bled before, where it sits, and — for lesions that need surgery — the experience of the team operating on it.

Risk of bleeding, in plain numbers

The best population data come from the Scottish Audit and the Mayo Clinic prospective cohort. Here's the short version:

Surgical outcomes by location

• Superficial (lobar) cavernomas — complete removal is achieved in over 95% of cases, with permanent neurological complications under 5% and durable seizure freedom in roughly 70-80% of patients whose seizures were caused by the lesion.
• Deep hemispheric (thalamus, basal ganglia) — selected, experienced centers report good outcomes, but the risk of a new permanent deficit is meaningfully higher than for lobar cases.
• Brainstem cavernomas — in modern series from high-volume centers, complete resection is achieved in 90-95% of cases, operative mortality is around 1%, and roughly 85% of patients are the same or better at long-term follow-up — with most of the early postoperative worsening recovering within 6-12 months.

The pattern is consistent across every major series: outcomes for cavernous malformation surgery, especially in the brainstem, track tightly with the experience of the surgical team. That is why where you have your surgery matters.

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