Management of lymphatic vascular malformations: A systematic review of the literature

Management and Outcomes of Pediatric Lymphatic Malformations: A Systematic Review From the APSA Outcomes and Evidence-Based Practice Committee

BACKGROUND

Significant variation in management strategies for lymphatic malformations (LMs) in children persists. The goal of this systematic review is to summarize outcomes for medical therapy, sclerotherapy, and surgery, and to provide evidence-based recommendations regarding the treatment.

METHODS

Three questions regarding LM management were generated according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Publicly available databases were queried to identify articles published from January 1, 1990, to December 31, 2021. A consensus statement of recommendations was generated in response to each question.

RESULTS

The initial search identified 9326 abstracts, each reviewed by two authors. A total of 600 abstracts met selection criteria for full manuscript review with 202 subsequently utilized for extraction of data. Medical therapy, such as sirolimus, can be used as an adjunct with percutaneous treatments or surgery, or for extensive LM. Sclerotherapy can achieve partial or complete response in over 90% of patients and is most effective for macrocystic lesions. Depending on the size, extent, and location of the malformation, surgery can be considered.

CONCLUSION

Evidence supporting best practices for the safety and effectiveness of management for LMs is currently of moderate quality. Many patients benefit from multi-modal treatment determined by the extent and type of LM. A multidisciplinary approach is recommended to determine the optimal individualized treatment for each patient.

LEVEL OF EVIDENCE: 4

Outcome of Sclerotherapy in a Preterm Infant with a Giant Fetal Neck Lymphatic Malformation: A Case Report

Introduction

Lymphatic malformation (LM), most commonly present in the neck area, is benign vascular malformations of the lymphatic system. In an infant, however, LM poses a high risk of adverse outcomes.

Case Presentation

We present a case with a giant fetal LM. Through ultrasonography, at 23+ weeks of gestation, a septate cystic mass 7.2×6.5×6.3 cm in size was found on the right side of the fetus's neck. After extensive counseling by the multidisciplinary team, the parents chose to continue the pregnancy. Severe fetal tracheal compression was observed at 29 weeks by magnetic resonance imaging (MRI). At 31 weeks and 5 days, owing to suspected fetal distress, an emergency cesarean section was performed and a male baby weighing 1720 g was delivered. The mass was 10×16×8 cm in size and ex utero intrapartum treatment (EXIT) was implemented. Due to progressive growth of the mass secondary to intralesional bleeding, an intralesional injection of bleomycin was administered three days later. This injection was repeated at the age of 1 month and 8 days. The baby was followed up and, by a year after his birth, LM had disappeared. The baby has since been in good health.

Conclusion

Accurate prenatal diagnosis and regular monitoring of a fetus with LM may improve prognosis. It is essential to have a trained multidisciplinary team to evaluate the condition of the fetus and the neonate and to provide treatment based on the evaluation. Our experience with intralesional bleomycin injection for the treatment of a giant fetal neck LM in a preterm infant had a favorable outcome. Long-term follow-up by a multidisciplinary team is needed in such cases.

Differences in Efficacy and Safety of Sirolimus and Sildenafil in Pediatric Lymphatic Malformations

OBJECTIVES

To explore the differences in the efficacy and safety of oral sirolimus and sildenafil in the treatment of pediatric intractable lymphatic malformations (LMs).

METHODS

From January 2014 to May 2022, we retrospectively enrolled children with intractable LMs treated with oral drugs (sirolimus or sildenafil) and divided the patients into sirolimus and sildenafil groups from Beijing Children's Hospital (BCH). Clinical features, treatment, and follow-up data were collected and analyzed. The indicators were the ratio of reduction in lesion volume pre and posttreatment, the number of patients with improved clinical symptoms, and adverse reactions to the two drugs.

RESULTS

Twenty-four children in the sildenafil group and 31 children in the sirolimus group were included in the present study. The effective rate in the sildenafil group was 54.2% (13/24), with a median lesion volume reduction ratio of 0.32 (-0.23, 0.89) and clinical symptoms improved in 19 patients (79.2%). On the contrary, the effective rate in the sirolimus group was 93.5% (29/31), with a median lesion volume reduction ratio of 0.68 (0.34, 0.96), and clinical symptoms improved in 30 patients (96.8%). There were significant differences (p < 0.05) between the two groups. Regarding safety, four patients in the sildenafil group and 23 patients in the sirolimus group with mild adverse reactions were reported.

CONCLUSION

Both sildenafil and sirolimus can reduce the volume of LMs and improve clinical symptoms in partial patients with intractable LMs. Sirolimus is more effective than sildenafil and the adverse reactions associated with both drugs are mild and controllable.

LEVEL OF EVIDENCE

III Laryngoscope, 133:3192-3199, 2023.

Sirolimus treatment for paediatric head and neck lymphatic malformations: a systematic review

PURPOSE

This PRISMA-compliant systematic review aimed to assess risks and benefits of sirolimus treatment for paediatric lymphatic malformations by focusing not only on treatment efficacy but also on possible treatment-related adverse events, and treatment combinations with other techniques.

METHODS

Search criteria were applied to MEDLINE, Embase, Web of Science, Scopus, Cochrane Library, and ClinicalTrials.gov databases and included all studies published up to March 2022 reporting paediatric lymphatic malformations treated with sirolimus. We selected all original studies that included treatment outcomes. After the removal of duplicates, selection of abstracts and full-text articles, and quality assessment, we reviewed eligible articles for patient demographics, lymphatic malformation type, size or stage, site, clinical response rates, sirolimus administration route and dose, related adverse events, follow-up time, and concurrent treatments.

RESULTS

Among 153 unique citations, 19 studies were considered eligible, with reported treatment data for 97 paediatric patients. Most studies (n = 9) were case reports. Clinical response was described for 89 patients, in whom 94 mild-to-moderate adverse events were reported. The most frequently administered treatment regimen was oral sirolimus 0.8 mg/m2 twice a day, with the aim of achieving a blood concentration of 10-15 ng/mL.

CONCLUSION

Despite promising results for sirolimus treatment in lymphatic malformation, the efficacy and safety profile of remains unclear due to the lack of high-quality studies. Systematic reporting of known side effects, especially in younger children, should assist clinicians in minimising treatment-associated risks. At the same time, we advocate for prospective multicentre studies with minimum reporting standards to facilitate improved candidate selection.

Microphysiological model of PIK3CA-driven vascular malformations reveals a role of dysregulated Rac1 and mTORC1/2 in lesion formation

Somatic activating mutations of PIK3CA are associated with development of vascular malformations (VMs). Here, we describe a microfluidic model of PIK3CA-driven VMs consisting of human umbilical vein endothelial cells expressing PIK3CA activating mutations embedded in three-dimensional hydrogels. We observed enlarged, irregular vessel phenotypes and the formation of cyst-like structures consistent with clinical signatures and not previously observed in cell culture models. Pathologic morphologies occurred concomitant with up-regulation of Rac1/p21-activated kinase (PAK), mitogen-activated protein kinase cascades (MEK/ERK), and mammalian target of rapamycin (mTORC1/2) signaling networks. We observed differential effects between alpelisib, a PIK3CA inhibitor, and rapamycin, an mTORC1 inhibitor, in mitigating matrix degradation and network topology. While both were effective in preventing vessel enlargement, rapamycin failed to reduce MEK/ERK and mTORC2 activity and resulted in hyperbranching, while inhibiting PAK, MEK1/2, and mTORC1/2 mitigates abnormal growth and vascular dilation. Collectively, these findings demonstrate an in vitro platform for VMs and establish a role of dysregulated Rac1/PAK and mTORC1/2 signaling in PIK3CA-driven VMs.

An overview of interventional radiology techniques for the diagnosis and management of vascular anomalies: Part 1

Minimally invasive percutaneous and endovascular strategies performed by interventional radiologists have become the mainstays of treatment for vascular anomalies, with improved outcomes, decreased complication rates, and reduced morbidity. The aim of this article is to introduce physicians who care for patients with vascular anomalies to state-of-the-art advancements in interventional radiology (IR) for diagnosis and treatment. Part 1 of this review will focus on sclerotherapy and cryoablation. Part 2 will discuss embolization, endovenous laser ablation, and image-guided percutaneous biopsy. Select vascular anomalies will be discussed as examples to highlight IR diagnostic and/or treatment techniques.

Annual prevalence estimation of lymphatic malformation with a cutaneous component: observational study of a national representative sample of physicians

Background

Lymphatic malformations (LMs) represent a potentially life-threatening, rare disease of the lymphatic system characterized by development of abnormal vessels, outpouchings, or cysts filled with lymphatic fluid. There are three morphologic types of LMs based on the size of the individual cysts: macrocystic (typically > 2 cm), microcystic (generally < 2 cm), and mixed (includes aspects of both). Macrocystic LMs typically exist beneath the skin and often can involve vascular components and/or organs. Microcystic LMs often have a cutaneous component and clinically present with lymphorrhea, bleeding, pain, itching, malodor, and functional deficits. There are no treatments approved by the US Food and Drug Administration (FDA) for either macrocystic or microcystic lymphatic malformations. The totality of the epidemiologic literature for LM is limited to the incidence of the disease among various birth cohorts. This is the first nationally representative study to estimate the national managed prevalence for patients with microcystic LM or combined LM with a cutaneous component annually across physician specialties likely to manage this condition. We conducted a retrospective observational survey of a nationally representative sample of patient-care physicians in the United States most likely to manage lymphatic malformations with a cutaneous component (LMC). Once recruited, target physicians participated via an electronic questionnaire. We weighted study physician self-estimates of the number of LMC patients treated in the past 12 months to reflect the specialists’ corresponding proportion in the national universe. All patient information was anonymous; no personally identifiable information was collected.

Results

Of the 420 physicians who visited the study website, 316 agreed to be screened and to participate (75.2% participation rate). Our survey results indicated the estimated number of unique annually managed LMC patients by target specialists is 79,920 (CI 66,600–93,250). This number corresponds to managed prevalence of 24.1 LMC patients per 100,000 population (CI 19.6/100,000–28.4/100,000).

Conclusions

The study indicates that while rare, LMC affects a substantial number of people in the US (79,920) who are being managed by one or more specialists. By better understanding the prevalence of people living with LMC who require treatment, efforts to both increase disease awareness and to identify underserved populations in need of potential new treatments can be better focused.

Genetic and Molecular Determinants of Lymphatic Malformations: Potential Targets for Therapy

Lymphatic malformations are fluid-filled congenital defects of lymphatic channels occurring in 1 in 6000 to 16,000 patients. There are various types, and they often exist in conjunction with other congenital anomalies and vascular malformations. Great strides have been made in understanding these malformations in recent years. This review summarize known molecular and embryological precursors for lymphangiogenesis. Gene mutations and dysregulations implicated in pathogenesis of lymphatic malformations are discussed. Finally, we touch on current and developing therapies with special attention on targeted biotherapeutics.

Vascular anomalies: clinical perspectives

Vascular anomalies are classified as vascular tumors or vascular malformations according to their cellular features and biological behavior. Detailed history and clinical assessment allow for the proper clinical diagnosis of most vascular anomalies and guide the choice of imaging to evaluate them. This article discusses the general information needed from a clinical history and physical exam to formulate a diagnosis of vascular anomaly. Then, the authors review the clinical findings from the most common vascular tumors and vascular malformations.

Management of Macrocystic Lymphatic Malformation in the Cervicofacial Region: Ultrasound-Guided Iodine Tincture Cauterization Combined With Intralesional Negative Pressure

PURPOSE

The purpose of our study was to evaluate the efficacy and safety of ultrasound-guided iodine tincture cauterization combined with postoperative intralesional negative pressure in the management of cervicofacial cystic lymphatic malformation (cLM).

METHOD

From January 2019 to July 2021, indocyanine green lymphography was performed preoperatively to confirm the lymph inflow, and this treatment was administered in 71 patients with cervicofacial cLM in our center. All cases were evaluated by curative effects, treatment frequency, and adverse events. The duration of posttreatment follow-up was from 12 to 14 months.

RESULTS

Indocyanine green lymphography indicated at least one lymphatic inflow in each cLM lesion. Excellent resolution was observed in 87.3% of cases, and good improvement of the treated cLM occurred in 9.9% of cases, and 2 cases with fair outcomes required subsequent treatment. It is noteworthy that no case was treated more than 3 times. Some minor adverse effects, including localized itch and scar, were managed by symptomatic treatment.

CONCLUSIONS

Because of satisfactory outcomes and low treatment frequency, ultrasound-guided iodine tincture cauterization combined with intralesional negative pressure represents an efficacious, safe, and feasible method for the management of macro-cLM in the cervicofacial region.

Lymphatic Anomalies in Children: Update on Imaging Diagnosis, Genetics and Treatment

Lymphatic anomalies comprise a spectrum of disorders ranging from common localized microcystic and macrocystic lymphatic malformations (LMs) to rare complex lymphatic anomalies, including generalized lymphatic anomaly, Kaposiform lymphangiomatosis, central conducting lymphatic anomaly, and Gorham-Stout disease. Imaging diagnosis of cystic LMs is generally straightforward, but complex lymphatic anomalies, particularly those with multi-organ involvement or diffuse disease, may be more challenging to diagnose. Complex lymphatic anomalies are rare but associated with high morbidity. Imaging plays an important role in their diagnosis, and radiologists may be the first clinicians to suggest the diagnosis. Furthermore, radiologists are regularly involved in management given the frequent need for image-guided interventions. For these reasons, it is crucial for radiologists to be familiar with the spectrum of entities comprising complex lymphatic anomalies and their typical imaging findings. In this article, we review the imaging findings of lymphatic anomalies, including LMs and complex lymphatic anomalies. We discuss characteristic imaging findings, multimodality imaging techniques used for evaluation, pearls and pitfalls in diagnosis, and potential complications. We also review recently discovered genetic changes underlying lymphatic anomaly development and the advent of new molecularly targeted therapies.

Lymphatic Malformations: Genetics, Mechanisms and Therapeutic Strategies

Lymphatic vessels maintain tissue fluid homeostasis by returning to blood circulation interstitial fluid that has extravasated from the blood capillaries. They provide a trafficking route for cells of the immune system, thus critically contributing to immune surveillance. Developmental or functional defects in the lymphatic vessels, their obstruction or damage, lead to accumulation of fluid in tissues, resulting in lymphedema. Here we discuss developmental lymphatic anomalies called lymphatic malformations and complex lymphatic anomalies that manifest as localized or multifocal lesions of the lymphatic vasculature, respectively. They are rare diseases that are caused mostly by somatic mutations and can present with variable symptoms based upon the size and location of the lesions composed of fluid-filled cisterns or channels. Substantial progress has been made recently in understanding the molecular basis of their pathogenesis through the identification of their genetic causes, combined with the elucidation of the underlying mechanisms in animal disease models and patient-derived lymphatic endothelial cells. Most of the solitary somatic mutations that cause lymphatic malformations and complex lymphatic anomalies occur in genes that encode components of oncogenic growth factor signal transduction pathways. This has led to successful repurposing of some targeted cancer therapeutics to the treatment of lymphatic malformations and complex lymphatic anomalies. Apart from the mutations that act as lymphatic endothelial cell-autonomous drivers of these anomalies, current evidence points to superimposed paracrine mechanisms that critically contribute to disease pathogenesis and thus provide additional targets for therapeutic intervention. Here, we review these advances and discuss new treatment strategies that are based on the recently identified molecular pathways.