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PubMed This is a summary of 18 peer-reviewed journal articles Updated
Neurology

Recognizing Symptoms and Warning Signs

At a Glance

Familial Cerebral Cavernous Malformation (FCCM) symptoms depend on the location of the lesions and often include seizures, headaches, and localized weakness. A sudden, explosive 'thunderclap' headache or new neurological deficits are medical emergencies requiring immediate evaluation.

While many people with Familial Cerebral Cavernous Malformation (FCCM) may not have symptoms for long periods, understanding how the condition can manifest is essential for proactive management. Because FCCM involves multiple lesions throughout the brain and body, symptoms can range from subtle skin changes to sudden neurological events [1][2].

Neurological Symptoms: The “Where” Matters

The symptoms you experience are usually determined by the location of the cavernous malformation in your brain or spinal cord [2][3].

  • Seizures: This is one of the most common symptoms of FCCM, especially if a lesion is near the surface of the brain (cortical proximity) [2][4]. Seizures are often caused by hemosiderin, a residue left behind from microscopic amounts of blood that leak from the malformation [2][5]. This iron-rich residue can irritate the surrounding brain tissue, creating an environment where seizures are more likely to occur [2][3].
  • Focal Neurological Deficits: These are “focused” problems, such as weakness in one arm, numbness on one side of the face, or double vision [2][6]. These occur when a lesion or a small leak affects a specific part of the brain responsible for that function. Lesions in the brainstem (the part of the brain connecting to the spinal cord) are more likely to cause these focal deficits [7][8].
  • Headaches: Many people with FCCM experience headaches. How do you tell the difference between a normal migraine and a “red flag” headache? A typical headache builds gradually. A “thunderclap” headache is explosive—reaching its maximum, excruciating intensity within seconds to minutes. This sudden, severe pain can be a sign of a new micro-hemorrhage and requires immediate ER evaluation [2][6].

The Mechanism of “Leaks”

It is helpful to think of a cavernous malformation as a tiny, berry-like cluster of leaky pipes [9][10]. In FCCM, these pipes are structurally weak [11]. A micro-hemorrhage occurs when a small amount of blood seeps through these weak walls [10]. Most of the time, this blood is reabsorbed by the body, but the iron it leaves behind can lead to the symptoms mentioned above [2][5].

Beyond the Brain: Skin and Other Signs

One of the most unique aspects of the familial form of this condition is that it can affect tissues outside the brain. These “extra-neural” signs can be vital clues for your doctors.

  • Hyperkeratotic Cutaneous Capillary-Venous Malformations (HCCVM): These are specific skin lesions often found in people with the CCM1 (KRIT1) mutation [12]. They typically look like deep blue nodules or spots that may feel slightly rough or “warty” on the surface [12][13]. They are harmless on their own but are a strong indicator of the genetic form of CCM [12].
  • Other Manifestations: Occasionally, FCCM can involve the eyes (retinal cavernomas) or the spine [14][15]. Retinal lesions look like “grape-like clusters” of blood vessels and are usually found during a dilated eye exam [14][16].

When to Seek Immediate Help

While FCCM is a chronic, manageable condition, certain “red flags” require an immediate evaluation in the Emergency Room:

  1. A sudden, severe “thunderclap” headache [2][6].
  2. New-onset seizures or a significant change in seizure frequency [17][2].
  3. Sudden weakness, numbness, or loss of vision [2][6].
  4. Rapid neurological decline or confusion [6][18].

In the emergency setting, doctors will typically use a high-sensitivity MRI to check for any new activity or bleeding. Learn more about how these scans work in Demystifying Your MRI and Imaging Results.

Common questions in this guide

What are the most common symptoms of familial cerebral cavernous malformation?
The most common symptoms of FCCM include seizures, headaches, and focal neurological deficits like weakness or numbness. The specific symptoms you experience depend primarily on the location of the malformations within your brain or spinal cord.
Why does FCCM cause seizures?
Seizures in FCCM are often triggered by an iron-rich residue called hemosiderin. This residue is left behind when the malformations leak microscopic amounts of blood, which irritates the surrounding brain tissue and creates an environment where seizures are more likely to occur.
How do I know if my headache is an FCCM emergency?
Normal headaches usually build gradually, whereas an FCCM emergency headache is often a 'thunderclap' headache. This type of headache is explosive, reaching excruciating intensity within seconds or minutes, and could signal a new micro-hemorrhage.
Can familial CCM affect the skin?
Some people with the genetic form of CCM develop deep blue, slightly rough skin lesions called HCCVMs. While harmless on their own, these bumps are a strong indicator of the underlying genetic condition, particularly the CCM1 mutation.
When should I go to the ER for FCCM symptoms?
You should seek emergency medical care if you experience a sudden, severe thunderclap headache, new or changing seizures, sudden weakness or vision loss, or rapid confusion. These red flags could indicate new bleeding that requires immediate evaluation with an MRI.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Do I have any 'high-risk' lesions in the brainstem or spinal cord?
  2. 2.Given my lesion location, what specific signs of a seizure should my family and I look for?
  3. 3.Should I have a skin exam by a dermatologist familiar with FCCM?
  4. 4.Are there specific 'red flag' symptoms that should prompt an immediate ER visit?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (18)
  1. 1

    Multiple cerebral cavernous malformations: Clinical course of confirmed, assumed and non-familial disease.

    Santos AN, Rauschenbach L, Saban D, et al.

    European journal of neurology 2022; (29(5)):1427-1434 doi:10.1111/ene.15253.

    PMID: 35060255
  2. 2

    Will There Be a Seizure? Predicting Seizures in Children (and Adults) with Familial Cerebral Cavernous Malformations.

    Joshi C

    Epilepsy currents 2022; (22(1)):36-37 doi:10.1177/15357597211069832.

    PMID: 35233195
  3. 3

    A small frontal lobe cavernoma presenting with headache mimicking migraine and complex focal seizure: A case report.

    Adhikari P, Nepali A, Shah A, et al.

    Clinical case reports 2024; (12(2)):e8472 doi:10.1002/ccr3.8472.

    PMID: 38323134
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    Symptomatic Hemorrhage From Cerebral Cavernous Malformations: Evidence from a Cohort Study.

    Gomez-Paz S, Maragkos GA, Salem MM, et al.

    World neurosurgery 2020; (135()):e477-e487 doi:10.1016/j.wneu.2019.12.035.

    PMID: 31843731
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    Is Extended Lesionectomy Needed for Patients with Cerebral Cavernous Malformations Presenting with Epilepsy? A Meta-Analysis.

    Shang-Guan HC, Wu ZY, Yao PS, et al.

    World neurosurgery 2018; (120()):e984-e990 doi:10.1016/j.wneu.2018.08.208.

    PMID: 30196170
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    Contralateral Interhemispheric Transfalcine Approach to the Basal Ganglia.

    Kalani MYS

    World neurosurgery 2024; (183()):93 doi:10.1016/j.wneu.2023.12.066.

    PMID: 38123129
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    Infratentorial Cerebral Cavernous Malformation May be a Risk Factor for Symptomatic Bleeding and Precocity of Symptoms: A Multicenter, Propensity Score Matched, Case-Control Study.

    Galvão GDF, Filho RC, Cunha AAM, et al.

    Current neurovascular research 2024; (21(2)):177-183 doi:10.2174/0115672026304601240307051654.

    PMID: 38482623
  8. 8

    Vertebral Intraosseous Vascular Malformations in a Familial Cerebral Cavernous Malformation Population: Prevalence, Histologic Features, and Associations With CNS Disease.

    Tandberg SR, Bocklage T, Bartlett MR, et al.

    AJR. American journal of roentgenology 2020; (214(2)):428-436 doi:10.2214/AJR.19.21492.

    PMID: 31825263
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    Quantitative Susceptibility Mapping in Cerebral Cavernous Malformations: Clinical Correlations.

    Tan H, Zhang L, Mikati AG, et al.

    AJNR. American journal of neuroradiology 2016; (37(7)):1209-15 doi:10.3174/ajnr.A4724.

    PMID: 26965464
  10. 10

    KRIT1 as a possible new player in melanoma aggressiveness.

    Ercoli J, Finetti F, Woodby B, et al.

    Archives of biochemistry and biophysics 2020; (691()):108483 doi:10.1016/j.abb.2020.108483.

    PMID: 32735866
  11. 11

    Familial cerebral cavernous malformation presenting with epilepsy caused by mutation in the CCM2 gene: A case report.

    Ishii K, Tozaka N, Tsutsumi S, et al.

    Medicine 2020; (99(29)):e19800 doi:10.1097/MD.0000000000019800.

    PMID: 32702807
  12. 12

    KRIT1-positive hyperkeratotic cutaneous capillary venous malformation.

    Matarneh B, Cottrell CE, Choi S, et al.

    Pediatric dermatology 2022; (39(2)):250-254 doi:10.1111/pde.14900.

    PMID: 34964173
  13. 13

    CCM3/PDCD10 gene mutation in cerebral cavernous malformations associated with hyperkeratotic cutaneous capillary venous malformations.

    Bilo L, Antenora A, Peluso S, et al.

    The Journal of dermatology 2016; (43(8)):962-3 doi:10.1111/1346-8138.13317.

    PMID: 26896283
  14. 14

    [Multimodal diagnostics of retinal cavernous hemangioma].

    Stoyukhina AS

    Vestnik oftalmologii 2023; (139(4)):52-58 doi:10.17116/oftalma202313904152.

    PMID: 37638572
  15. 15

    Spinal involvement in pediatric familial cavernous malformation syndrome.

    Geraldo AF, Luis A, Alves CAPF, et al.

    Neuroradiology 2022; (64(8)):1671-1679 doi:10.1007/s00234-022-02958-1.

    PMID: 35451625
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    Noninvasive Structural Imaging of a Retinal Cavernous Hemangioma Using SS-OCTA and Correlation to Previously Reported Histopathology.

    Zheng A, Boss J, Rachitskaya AV

    Ophthalmic surgery, lasers & imaging retina 2019; (50(11)):e320-e323 doi:10.3928/23258160-20191031-20.

    PMID: 31755984
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    Seizure Incidence Rates in Children and Adults With Familial Cerebral Cavernous Malformations.

    Fox CK, Nelson J, McCulloch CE, et al.

    Neurology 2021; (97(12)):e1210-e1216 doi:10.1212/WNL.0000000000012569.

    PMID: 34389651
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    Successful treatment of hemorrhagic brainstem cavernous malformation with hematoma evacuation and postoperative propranolol.

    Hoffman JE, Ryan M, Wittenberg B, et al.

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This page covers symptoms and warning signs of FCCM for educational purposes only. Always consult your neurologist or go to the nearest emergency room if you experience sudden, severe symptoms like a thunderclap headache.

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