Temporal Evolution and Management of Fast Flow Vascular Anomalies in PTEN Hamartoma Tumor Syndrome

Extracranial arteriovenous malformations: towards etiology-based therapeutic management

Anomalies during angiogenesis can initiate the formation of arteriovenous malformations (AVMs), characterized by aberrant connections between arteries and veins and fast lesional blood flow. These anomalies can manifest anywhere in the body, including the brain, and they typically appear at birth and evolve alongside growth of the individual. Depending on their location and size, AVMs can induce progressive deformation, chronic pain, functional impairment, and ulceration and pose life-threatening risks such as hemorrhage and organ dysfunction. The primary treatment modalities entail surgical intervention or embolization followed by surgery. However, these approaches are often challenging and seldom offer definitive resolution. In addition, inadequately performed surgery may trigger angiogenic rebound, fostering AVM recurrence. Advancements in comprehending the molecular pathways underlying AVMs have sparked interest in repurposing targeted therapies initially devised for cancer treatment. The first results are promising, giving new hope to the patients affected with these often devastating and debilitating lesions, the management of which presents major clinical challenges.

Clinical Neurologic Features and Evaluation of PTEN Hamartoma Tumor Syndrome: A Systematic Review

BACKGROUND AND OBJECTIVES

PTEN hamartoma tumor syndrome (PHTS) is a well-recognized hereditary tumor syndrome and is now also recognized as a common cause of monogenic autism spectrum disorder. There is a vast spectrum of phenotypic variability across individuals with PHTS, and in addition to neurodevelopmental challenges, patients with PHTS may experience a wide variety of neurologic challenges, many of which have only recently been described. Thus, this systematic review aimed to summarize the breadth of the current knowledge of neurologic conditions in individuals with PHTS.

METHODS

We conducted a systematic review using the MEDLINE and EMBASE databases until January 2023. We included studies that reported neurologic signs, symptoms, and diagnoses in patients with a diagnosis of PHTS. Two independent reviewers extracted data (neurologic diagnoses and patient details) from each study. Case reports, case series, prospective studies, and therapeutic trials were included. We assessed the quality of evidence using the appropriate tool from the JBI, depending on study design.

RESULTS

One thousand nine hundred ninety-six articles were screened, and 90 articles met the inclusion criteria. The majority of the included studies were case reports (49/90, 54%) or small case series (31/90, 34%). Epilepsy secondary to cerebral malformations, neurologic deficits from spinal or cranial arteriovenous malformations, and rare tumors such as dysplastic cerebellar gangliocytoma are among the more severe neurologic features reported across patients with PHTS. One interventional randomized control trial examining neurocognitive endpoints was identified and did not meet its efficacy endpoint.

DISCUSSION

Our systematic review defines a broad scope of neurologic comorbidities occurring in individuals with PHTS. Neurologic findings can be categorized by age at onset in individuals with PTHS. Our study highlights the need for additional clinical trial endpoints, informed by the neurologic challenges faced by individuals with PHTS.

What the Interventional Radiologist Needs to Know about the Genetics of Vascular Anomalies

The purpose of this article is to familiarize the reader with the basic genetics and vascular biology behind the array of vascular anomalies they may encounter in their practice. Individuals with vascular malformations are often referred to multidisciplinary clinics composed of diverse specialists all with the same goal: how to provide the best care possible. The team is typically composed of physicians, nurses, social workers, and technical staff from multiple specialties including diagnostic and interventional radiology, dermatology, hematology/oncology, otolaryngology, plastic surgery, and several additional subspecialties. Imaging plays a crucial role in diagnosis and treatment planning, but increasingly biopsies are needed for more accurate histopathological and genetic information to inform the plan of treatment, as well as for counseling patients and their families on the natural history, heritability, and long-term prognosis of the condition. Understanding the molecular mechanism that gives rise to vascular anomalies is crucial for arriving at the proper diagnosis and choosing among treatment options. As oncological medications are being increasingly repurposed to treat vascular malformations, it is vital for those caring for patients with vascular anomalies to understand how these anomalies develop, and which drug may be appropriate to repurpose for this benign disease.

Arteriovenous malformations as a presenting sign of PTEN hamartoma tumor syndrome: A case series

High-flow vascular malformations have been associated with multiple syndromes including capillary malformation-arteriovenous malformation (CM-AVM) syndrome, hereditary hemorrhagic telangiectasia syndrome, and less commonly, phosphatase and tensin homolog hamartoma tumor syndrome (PHTS). We present a series of three patients with clinically challenging complex AVMs who were found to have underlying PHTS. In all patients, diagnosis was delayed, and the presence of the AVM prompted sampling and genetic testing for PHTS in the absence of other clinical features of the condition. This series highlights the importance of screening for PHTS in the setting of high-flow vascular malformations.

Medical Therapeutics for the Treatment of Vascular Anomalies: Part 3

The discovery of inherited and somatic genetic mutations, along with advancements in clinical and scientific research, has improved the understanding of vascular anomalies and changed the treatment paradigm. With the aim of minimizing the need for invasive procedures and improving disease outcomes, molecularly targeted medications and anti-angiogenesis agents have become important as both adjuncts to surgery, and increasingly, as the primary treatment of vascular anomalies. This article highlights the commonly used and emerging therapeutic medications for nonmalignant vascular tumors and vascular malformations.

A narrative review of the role of sirolimus in the treatment of congenital vascular malformations

OBJECTIVE

Vascular malformations arise from defects in the morphologic development of the vascular system and can have an impact on quality of life and/or lead to severe complications. To date, vascular malformations are frequently managed by invasive techniques, after which recurrence is common. Sirolimus, a downstream inhibitor of the phosphatidylinositol 3 kinase/AKT pathway and best known for its immunosuppressive effect, has been used off-label for lesions for which approved therapies were associated with unsatisfactory results or recurrence. The aim of this study was to review the available data on the effect of sirolimus on the size and symptoms of different types of malformations and to summarize the main safety issues.

METHODS

A literature search in Pubmed, Embase, Web of Science, and SCOPUS was performed. Case reports, case series, and clinical trials evaluating the effect of sirolimus in vascular malformations were eligible for this review. Fully terminated studies published between January 2010 and May 2019 reporting an evaluable response on size and/or symptoms were included. Relevant data on lesion size, symptoms, side effects and duration of treatment were extracted as reported in the study. Additionally, we reported 10 unpublished cases who were treated in UZ Leuven.

RESULTS

The literature review included 68 articles, describing 324 patients. The median duration of therapy was 12 months (range, 1-60 months). After 6 months of treatment, the size of the malformation had at least decreased in 67% of patients with common venous malformations (VM), in 93% of patients with blue rubber bleb nevus syndrome and in all patients with verrucous VM. The size of lymphatic malformations improved in more than 80% of the patients, even in the case of extensive involvement such as in Gorham-Stout disease and generalized lymphatic anomaly. In addition, the majority of patients with syndromic vascular malformations experienced a decrease in size and reported symptoms improved in almost all patients, regardless of the type of malformation. Side effects were common (53%) but usually mild; mucositis and bone marrow suppression were the most common. Regrowth or recurrence of symptoms occurred in 49% of patients who discontinued treatment. Comparable effects were seen in our own patients.

CONCLUSIONS

This review shows that sirolimus is effective in decreasing the size and/or symptoms of particularly lymphatic malformations as well as VMs. Although common, side effects were usually mild. Nevertheless, clinical trials are needed to confirm the safety and effectivity of sirolimus and to identify the required serum levels and duration of treatment.

Antiangiogenic agent as a novel treatment for pediatric intracranial arteriovenous malformations: case report

Intracerebral arteriovenous malformations (AVMs) are high-flow collections of abnormal vessels and a common cause of pediatric intracranial hemorrhage. There are few treatment options available for AVMs not amenable to surgical resection, endovascular embolization, radiosurgery, or multimodality treatment. The authors sought to review the molecular and genetic pathways that have been implicated in the formation of AVMs, focusing on the possibility of medically targeting these pathways in the treatment of AVMs. In the novel case presented here, a pediatric patient who was diagnosed with an intracranial AVM unamenable to conventional treatments underwent alternative treatment with molecular pathway inhibitors.

PTEN Hamartoma Tumor Syndrome: A Clinical Overview

The phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) is a grouping of related genetic disorders that has been linked to germline mutations in the PTEN gene. These disorders include Cowden syndrome (CS), Bannayan–Riley–Ruvalcaba syndrome, adult Lhermitte–Duclos disease, and autism spectrum disorders associated with macrocephaly. The majority of the clinical information available on PHTS, however, is related to individuals diagnosed with CS. There is still much to be learned about this disorder, since diagnostic criteria for CS were only established in 1996, before the identification of the PTEN gene, and were based primarily on features seen in cases reported in the existing literature. More recently, however, data from several large series of patients have shown that a number of the clinical features associated with PTEN mutations are either more or less common than previously reported. In addition, we now know that only about 30–35% of patients meeting clinical diagnostic criteria for Cowden syndrome actually have a detectable PTEN mutation. Thus, our understanding of PTEN-related diseases and their management has evolved significantly over time. The United States National Comprehensive Cancer Network (NCCN) has produced and regularly updates practice guidelines which include clinical diagnostic criteria as well as guidelines for PTEN testing and management of patients with mutations. This review will summarize the overall literature on PHTS as well as recent findings which are broadening our understanding of this set of disorders.