Capillary Venous Malformation With Undergrowth and Activating PIK3CA Variant: An Underrecognized Phenotype.

Congenital vascular malformations associated with segmental overgrowth and PIK3CA variants are well-documented and are classified within the PIK3CA-related overgrowth spectrum (PROS), yet PIK3CA-associated segmental undergrowth is a less understood entity. We present a case of a patient with a capillary venous malformation (CVM) and limb undergrowth associated with a pathogenic PIK3CA variant (p.Glu453Lys). An updated classification system should be considered to more broadly encompass variable phenotypic presentations of PIK3CA-related disorders, including segmental undergrowth. We propose novel terminology such as PIK3CA-related altered growth spectrum (PRAGS).