Kaposiform hemangioendothelioma further broadens the phenotype of PIK3CA-related overgrowth spectrum

Kaposiform hemangioendothelioma (KHE) is a rare locally aggressive mixed vascular tumor, with typical onset in early childhood and characterized by progressive angio- and lymphangiogenesis. Its etiopathogenesis and molecular bases are still unclear. Here, we report the first case of congenital KHE harboring a PIK3CA mosaic pathogenic variant (c.323G > A, p.Arg108His) in a boy with very subtle PIK3CA-related overgrowth spectrum (PROS) features. This finding provides insights into the pathophysiology of KHE, offering targeted therapeutic options by inhibition of the PI3K/Akt/mTOR pathway. We propose the inclusion of this mixed lymphatic and vascular anomaly within the PROS.

Automated summary

Kaposiform hemangioendothelioma (KHE) is a rare mixed vascular tumor characterized by local aggressiveness and progressive angiogenesis, typically occurring in early childhood. The first reported case of congenital KHE with a PIK3CA mosaic pathogenic variant sheds light on the pathophysiology of KHE and suggests targeted therapeutic options. The authors propose the inclusion of this anomaly within the PIK3CA-related overgrowth spectrum (PROS).