Macrocephaly-capillary malformation in Infant/Neonate
M-CM is caused by a somatic mutation in PIK3CA. As such, there are no known risk factors or predisposing medical history. Reports are mixed regarding sex predominance. The condition is rare, with fewer than 200 cases in the literature.
M-CM was initially labeled as macrocephaly-cutis marmorata telangiectasia congenita (M-CMTC). The name was changed to M-CM when it was realized these patients had a CM rather than cutis marmorata telangiectasia congenita. Older literature may describe patients with M-CM as having M-CMTC, or may use another term, megalencephaly-capillary malformation-polymicrogyria (MCAP).
Q87.3 – Congenital malformation syndromes involving early overgrowth
431770003 – Fetal macrocephaly
Differential Diagnosis & Pitfalls
- Cutis marmorata telangiectatica congenita (CMTC) – Presents at birth in a reticulated, depressed, serpiginous pattern. Can have atrophy of the dermis and subcutis. Punctate ulcerations are possible. Fades over first year of life.
- Sturge-Weber syndrome – Facial capillary malformation involving at least one upper eyelid and the forehead. Usually has neurological symptoms, such as seizures.
- CLOVES syndrome (congenital lipomatous overgrowth, vascular malformations, epidermal nevi, skeletal anomalies) – Can have capillary malformations and body asymmetry but does not usually have neurological findings. Same genetic mutation.
- Diffuse capillary malformation with overgrowth – Reticulate capillary malformation extending across multiple contiguous anatomic regions. Asymmetry / overgrowth may be present, but patients are normocephalic and lack neurological symptoms.