Wound-Healing Problems Associated with Combined Vascular Malformations in Klippel-Trenaunay Syndrome

Diagnosis of a chronic wound in the special case of a vascular malformation: A proposal of the Wound and Healing Group of the French Society of Vascular Medicine

Vascular malformations can present with a variety of symptoms and an unpredictable course with the occurrence of wounds. Ulcerations in patients with vascular malformations are fortunately rare. Although few data exist, complications may involve a variety of mechanistic or hemodynamic factors. A rigorous etiological and vascular assessment is therefore essential. In view of the paucity of recommendations, the Wound and Healing Group of the French Society of Vascular Medicine, based on the literature on the subject, presents a number of suggestions for the diagnosis and management of wounds associated with vascular malformations.

Targeted next-generation sequencing for detection of PIK3CA mutations in archival tissues from patients with Klippel-Trenaunay syndrome in an Asian population : List the full names and institutional addresses for all authors

BACKGROUND

Klippel-Trenaunay syndrome (KTS) is a rare slow-flow combined vascular malformation with limb hypertrophy. KTS is thought to lie on the PIK3CA-related overgrowth spectrum, but reports are limited. PIK3CA encodes p110α, a catalytic subunit of phosphatidylinositol 3-kinase (PI3K) that plays an essential role in the PI3K/AKT/mammalian target of rapamycin (mTOR) signaling pathway. We aimed to demonstrate the clinical utility of targeted next-generation sequencing (NGS) in identifying PIK3CA mosaicism in archival formalin-fixed paraffin-embedded (FFPE) tissues from patients with KTS.

RESULTS

Participants were 9 female and 5 male patients with KTS diagnosed as capillaro-venous malformation (CVM) or capillaro-lymphatico-venous malformation (CLVM). Median age at resection was 14 years (range, 5-57 years). Median archival period before DNA extraction from FFPE tissues was 5.4 years (range, 3-7 years). NGS-based sequencing of PIK3CA achieved an amplicon mean coverage of 119,000x. PIK3CA missense mutations were found in 12 of 14 patients (85.7%; 6/8 CVM and 6/6 CLVM), with 8 patients showing the hotspot variants E542K, E545K, H1047R, and H1047L. The non-hotspot PIK3CA variants C420R, Q546K, and Q546R were identified in 4 patients. Overall, the mean variant allele frequency for identified PIK3CA variants was 6.9% (range, 1.6-17.4%). All patients with geographic capillary malformation, histopathological lymphatic malformation or macrodactyly of the foot had PIK3CA variants. No genotype-phenotype association between hotspot and non-hotspot PIK3CA variants was found. Histologically, the vessels and adipose tissues of the lesions showed phosphorylation of the proteins in the PI3K/AKT/mTOR signaling pathway, including p-AKT, p-mTOR, and p-4EBP1.

CONCLUSIONS

The PI3K/AKT/mTOR pathway in mesenchymal tissues was activated in patients with KTS. Amplicon-based targeted NGS could identify low-level mosaicism from low-input DNA extracted from FFPE tissues, potentially providing a diagnostic option for personalized medicine with inhibitors of the PI3K/AKT/mTOR signaling pathway.

PIK3CA vascular overgrowth syndromes: an update

PURPOSE OF REVIEW

Over the past decade many previously poorly understood vascular malformation disorders have been linked to somatic activating mutations in PIK3CA, which regulates cell survival and growth via activation of the mTOR1-AKT pathway. The goal of this article is to describe and provide an update on the clinical features, complications, and management strategies for the PIK3CA-related overgrowth spectrum (PROS).

RECENT FINDINGS

PROS encompasses a heterogenous group of disorders with complications related to the tissues harboring the mutation. Vascular malformation syndromes, such as Klippel-Trenaunay syndrome and Congenital Lipomatous Overgrowth Vascular malformations Epidermal nevi and Skeletal abnormalities, have an increased risk of thromboembolic complications, which is accentuated postprocedurally. Asymmetric overgrowth, particularly of limbs, results in a high rate of orthopedic complications. Hypoglycemia screening in the neonatal period and ongoing monitoring for growth failure is recommended in megalencephaly capillary malformation due to its association with multiple endocrinopathies. Recently, sirolimus, an mTOR1 inhibitor, has shown promise in vascular anomalies and now PROS. PIK3CA direct inhibitor, Alpelisib (BYL719), was recently trialed with significant clinical benefit.

SUMMARY

As the pathogenesis of these conditions is better elucidated and targeted treatments are developed, recognizing the clinical features, comorbidities, and evolving therapeutic landscape across the PROS spectrum becomes more crucial for optimization of care.