Macrocephaly-capillary malformation

Author: Dr Elizabeth A Connelly, Dermatologist, New Plymouth, New Zealand. Chief Editor: Adjunct A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand, July 2017.

What is macrocephaly-capillary malformation?

Macrocephaly-capillary malformation (MCM) was first described in 1997 and is characterised by:

  • Macrocephaly
  • Cutaneous vascular anomalies
  • Polymicrogyria. 

Additional features include variable degrees of asymmetric somatic overgrowth, distal limb malformations, and hyperelasticity.  Fewer than 300 cases have been reported in the literature.

MCM also known as megalencephaly-capillary malformation syndrome, and megalencephaly-capillary malformation-polymicrogyria (MCAP) syndrome, to reflect very large brain size, large head size, and polymicrogyria that characterise the syndrome.

Who gets MCM/MCAP?

MCM/ MCAP affects boys and girls equally with no ethnic predilections.  It occurs sporadically.

What causes MCM/ MCAP?

Some cases of MCM/MCAP have been found to have somatic mutations in the phosphatidylinositol 3-kinase, catalytic, alpha polypeptide (PIK3CA) gene on chromosome 3q26.

What are the clinical features of MCM/MCAP?

Major criteria: both must be present

Minor criteria: variable involvement

  • Asymmetrical overgrowth
  • Developmental delay
  • Midline facial capillary malformation
  • Neonatal hypotonia
  • Syndactyly
  • Frontal bossing
  • Joint hypermobility, hyperelastic skin, doughy skin
  • Hydrocephalus
  • Seizures

How is the diagnosis of MCM/ MCAP made?

Diagnosis is made based on clinical signs and neuro-imaging studies. Both major criteria should be present, with variable minor criteria.

Baseline magnetic resonance imaging (MRI) of the brain and spine is recommended at the time of diagnosis.

What is the differential diagnosis for MCM/MCAP?

MCAP should be distinguished from other overgrowth syndromes with vascular malformations including:

Management and outcome of MCM/ MCAP

Patients with MCM/MCAP require ongoing medical surveillance as well as physical and occupational therapy. Early intervention is helpful to overcome disability and achieve developmental milestones.

Patients are at increased risk of developing meduloblastoma, meningioma, Wilms tumour and leukaemia over their lifetime. 

In addition to yearly medical exams, all patients should have cardiology consultation at the time of diagnosis.

Follow-up imaging recommendations include:

  • Magnetic resonance imaging (MRI) of the brain at diagnosis and every 6 months until age 2
  • Serial abdominal sonography every 3-6 months for the first 7 years of life. 

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Related information



  • Gonzalez ME, Burk CJ, Barbouth DS, Connelly EA. Macrocephaly-capillary malformation: a report of three cases and review of the literature. Pediatr Dermatol. 2009 May-Jun;26(3):342-6. PubMed.
  • Wright DR, Frieden IJ, Orlow SJ, Shin HT, Chamlin S, Schaffer JV, Paller AS. The misnomer “Macrocephaly-Cutis Marmorata Telangectatica Congenita Syndrome” Report of 12 new cases and support for revising the name to macrocephaly-capillary malformation. Arch Dermatol. 2009;145(3):287-293. PubMed.

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