Management Guidelines

In June 2012, the discovery of the genetic mutation responsible for M-CM was published and the first set of clinical management guidelines was included in a supplement.  The authors acknowledge that these guidelines are provisional and will surely change as understanding about M-CM grows.  Note that this paper refers to M-CM as MCAP.


The guidelines summarized:

  1. Clinic evaluations no less than every 6 months for the first ~6 years of life, and at least yearly thereafter. Special attention should be paid to a possible elevated risk of cancer and neurological symptoms.  Follow up testing should be administered for any positive symptoms reported or exam findings.
  2. Baseline brain and spinal cord MRI imaging at the time of diagnosis. Repeat brain MRI every 6 months from 0-2 years and every year from 2-6 years. The need for imaging in older patients depends on prior findings and clinical course.
  3. Kidney cancer (Wilms tumor) screening following the guidelines for Beckwith-Wiedemann syndrome: renal ultrasounds every 3 months to age 8 years.  The AFP blood test indicated for Beckwith-Wiedemann syndrome to detect hepatoblastoma (liver cancer) is not recommended at this time -- there have been no reported cases in M-CM.
  4. Baseline echocardiogram and electrocardiogram with a pediatric cardiologist to evaluate for cardiovascular malformations and rhythm abnormalities.
  5. Baseline thrombophilia evaluation.

Prior to this publication, there was little consensus among researchers about the need for cancer screening in M-CM.  There is no new evidence about cancer incidence in M-CM, but the gene mutation that is now thought to cause M-CM, PIK3CA, is found mutated in cancer.  Additionally, PIK3CA has recently been implicated in CLOVES syndrome, where a Wilms tumor risk has been more clearly demonstrated.


Increased reports of hypoglycemia have emerged in the scientific literature and in the patient community in association with M-CM (aka MCAP) and related megalencephaly conditions. A 2017 paper, Hypoglycaemia Represents a Clinically Significant Manifestation of PIK3CA- and CCND2- Associated Segmental Overgrowth,  states the following:

"The current evaluation of children with MCAP and MPPH does not standardly include investigation of hypoglycaemia. We suggest screening for low blood sugars regularly during the neonatal period and review by an endocrinologist if hypoglycaemia is detected in patients with MCAP or MPPH to allow better preparation for illnesses or periods of fasting. Furthermore, a controlled fast may be reasonable in patients with MPPH or MCAP to identify hypoglycaemic risk prior to sedation for neuroimaging which is recommended regularly in early life."