The megalencephaly-capillary malformation (MCAP) syndrome is a rare disorder characterized by prenatal overgrowth, somatic and cerebral asymmetry, cutaneous vascular malformations, and connective tissues abnormalities. 1 The central nervous system (CNS) and cutaneous manifestations dominate the clinical picture during postnatal life. Structural cardiac, pulmonary, and lymphatic abnormalities are not commonly seen, although two previously reported patients were noted to have fetal hydrops or fetal pleural effusions. 2 Recently, de novo germline and postzygotic mutations in three genes within the PI3K-AKT signaling pathway (AKT3, PIK3R2, and PIK3CA) were reported to cause a group of related meglancephaly syndromes, including MCAP and the megalencephaly-postaxial polydactylypolymicrogyria-hydrocephalus (MPPH) syndrome. 3