Extensive Cystic lymphatic malformation with PIK3CA-Related Overgrowth Spectrum: Prenatal Diagnosis and Autopsy Findings in 3 Fetal Cases.

Objective: To describe and discuss prenatal imaging and post-termination pathological features of extensive cystic lymphatic malformation (CLM) associated with PIK3CA mutation of PROS.

Methods: We reviewed prenatal imaging and pathological features of three cases of extensive CLM involving the inferior limb extending on the body diagnosed in the second trimester, which were terminated based on the anatomical extension of this vascular malformation.

Results: Major asymmetrical soft tissue limb hypertrophy associated with extremities anomalies as well as cystic soft tissue infiltration extending to the body were present in the three cases without any cerebral anomalies. Foetopathological examination performed after TOP confirmed prenatal features, which were suggestive of PROS. Molecular analysis of affected tissues revealed an activating somatic mutation of the PIK3CA gene in all cases.

Conclusion: Such prenatal diagnosis is crucial for prenatal counseling in the light of promising targeted therapy leading to orientate the couple.