PIK3CA-related overgrowth spectrum (PROS) is a broad group of segmental overgrowth disorders that can occur with or without associated vascular anomalies, caused by activating mutations in the PIK3CA gene, which are also responsible for the vast majority of isolated lymphatic malformations and some isolated venous malformations 1.
Pathology
Mutations in the PIK3CA gene are most commonly somatic mosaic mutations, caused by sporadic non-hereditary mutations in only parts of the body, but can rarely be caused by germline mutations.
PROS disorders include 1:
fibroadipose hyperplasia or overgrowth (FAO)
hemihyperplasia multiple lipomatosis (HHML)
fibroadipose Infiltrating lipomatosis / facial infiltrative lipomatosis
Some authors also consider fibroadipose vascular anomaly (FAVA) as being a PROS disorder 2.