Analysis of the Occurrence of PIK3CA Gene Mutation in Children with Lymphatic Malformation—Single Center Study

<b>Background</b>: Lymphatic malformations (LM) are rare congenital vascular anomalies caused by abnormal development and growth of lymphatic vessels. These malformations can lead to a wide range of symptoms, from mild swelling to more severe complications. Treatment options remain limited, especially for complex cases. Recent research has suggested that <i>PIK3CA</i> mutations play a key role in the pathogenesis of LM, potentially offering new possibilities for targeted treatment strategies. <b>Methods</b>: In this study, a cohort of 36 patients diagnosed with LM, Klippel-Trenaunay syndrome (KTS), and Proteus syndrome was analyzed. <i>PIK3CA</i> mutations were assessed in tissue samples obtained from the LM during clinically indicated procedures using digital droplet polymerase chain reaction (ddPCR), targeting five hotspots. <b>Results</b>: <i>PIK3CA</i> mutations were found in 18 patients (50%). The most frequent mutation was p.E542K (<i>c.1624G>A</i>), found in 19.44% of patients, followed by p.H1047R (<i>c.3149A>G</i>), p.E545K (<i>c.1633G>A</i>), and p.H1047L (<i>c.3140A>T</i>) each occurring in 11.11% of the cases. Mutations were more common in isolated LMs, with 63.16% of patients exhibiting <i>PIK3CA</i> mutations. <b>Conclusions</b>: <i>PIK3CA</i> mutations are common in LM, supporting the potential for targeted therapies like PI3K inhibitors in treating complex cases. This research highlights the importance of genetic analysis in the management of LM and offers a new therapeutic approach.