Vascular Anomalies

Generalized lymphatic anomalies and review of the current management landscape: a case report and review of the literature

BACKGROUND

Generalized lymphatic anomaly previously known as diffuse systemic lymphangiomatosis is a rare multisystem congenital disease arising from the lymphatic system, and it is characterized by abnormal proliferation of the lymphatic channels in osseous and extraosseous tissues. It typically affects children or young adults. Although it is benign, it can be misdiagnosed as malignancy because of its diffuse and debilitating nature depending on the site of involvement. Due to its rarity, diagnosis is often delayed, leading to potential significant morbidity or mortality if vital organs are involved. Furthermore, its potential for multiorgan involvement with no curative treatment makes its management challenging.

CASE PRESENTATION

We describe a case of a 35-year-old Caucasian female, who presented with epigastric pain and was subsequently extensively investigated at multiple tertiary centers by numerous specialists for query malignancy and metabolic bone disorder following incidental computed tomography imaging findings of multiple osteolytic lesions in the axial skeleton, and low-attenuating lesions in the axilla, spleen, and mediastinum. The diagnosis was confirmed with an axillary excisional biopsy. She was clinically stable with no end organ damage. She was monitored conservatively.

CONCLUSIONS

The case illustrates the importance of increased awareness among clinicians for this rare congenital disease to enable earlier diagnosis and to avoid unnecessary invasive investigations. Furthermore, this case highlights the potential need for multiple biopsies of affected sites to confirm diagnosis. We also discuss the emergence of interferon therapy, chemotherapy, immunosuppression, and immunotherapy as medical management for this condition.

A review of mechanisms of disease across PIK3CA-related disorders with vascular manifestations

BACKGROUND

PIK3CA-related disorders include vascular malformations and overgrowth of various tissues that are caused by postzygotic, somatic variants in the gene encoding phosphatidylinositol-3-kinase (PI3K) catalytic subunit alpha. These mutations result in activation of the PI3K/AKT/mTOR signaling pathway. The goals of this review are to provide education on the underlying mechanism of disease for this group of rare conditions and to summarize recent advancements in the understanding of, as well as current and emerging treatment options for PIK3CA-related disorders.

MAIN BODY

PIK3CA-related disorders include PIK3CA-related overgrowth spectrum (PROS), PIK3CA-related vascular malformations, and PIK3CA-related nonvascular lesions. Somatic activating mutations (predominantly in hotspots in the helical and kinase domains of PIK3CA, but also in other domains), lead to hyperactivation of the PI3K signaling pathway, which results in abnormal tissue growth. Diagnosis is complicated by the variability and overlap in phenotypes associated with PIK3CA-related disorders and should be performed by clinicians with the required expertise along with coordinated care from a multidisciplinary team. Although tissue mosaicism presents challenges for confirmation of PIK3CA mutations, next-generation sequencing and tissue selection have improved detection. Clinical improvement, radiological response, and patient-reported outcomes are typically used to assess treatment response in clinical studies of patients with PIK3CA-related disorders, but objective assessment of treatment response is difficult using imaging (due to the heterogeneous nature of these disorders, superimposed upon patient growth and development). Despite their limitations, patient-reported outcome tools may be best suited to gauge patient improvement. New therapeutic options are needed to provide an alternative or supplement to standard approaches such as surgery and sclerotherapy. Currently, there are no systemic agents that have regulatory approval for these disorders, but the mTOR inhibitor sirolimus has been used for several years in clinical trials and off label to address symptoms. There are also other agents under investigation for PIK3CA-related disorders that act as inhibitors to target different components of the PI3K signaling pathway including AKT (miransertib) and PI3K alpha (alpelisib).

CONCLUSION

Management of patients with PIK3CA-related disorders requires a multidisciplinary approach. Further results from ongoing clinical studies of agents targeting the PI3K pathway are highly anticipated.

Medical Adjuvants in the Treatment of Surgically Refractory Arteriovenous Malformations of the Head and Face: Case Report and Review of Literature

BACKGROUND

Arteriovenous malformations (AVMs) of the brain and face present unique challenges for clinicians. Cerebral AVMs may induce hemorrhage or form aneurysms, while facial AVMs can cause significant disfigurement and pain. Moreover, facial AVMs often draw blood supply from arteries providing critical blood flow to other important structures of the head which may make them impossible to treat curatively. Medical adjuvants may be an important consideration in the management of these patients.

SUMMARY

We conducted a systematic review of the literature to identify other instances of molecular target of rapamycin (mTOR) inhibitors used as medical adjuvants for the treatment of cranial and facial AVMs. We also present 2 cases from our own institution where patients were treated with partial embolization, followed by adjuvant therapy with rapamycin. After screening a total of 75 articles, 7 were identified which described use of rapamycin in the treatment of inoperable cranial or facial AVM. In total, 21 cases were reviewed. The median treatment duration was 12 months (3-24.5 months), and the highest recorded dose was 3.5 mg/m2. 76.2% of patients demonstrated at least a partial response to rapamycin therapy. In 2 patients treated at our institution, symptomatic and radiographic improvement were noted 6 months after initiation of therapy. Key Messages: Early results have been encouraging in a small number of patients with inoperable AVM of the head and face treated with mTOR inhibitors. Further study of medical adjuvants such as rapamycin may be worthwhile.

Venous malformations

The often inexorable growth and expansion of congenital vascular malformations can result in substantial morbidity and, in some cases, premature death of these patients. Despite this, patients suffering from such lesions are often erroneously diagnosed and/or inadequately treated, due to a lack of expertise among primary care practitioners as well as specialists. Venous malformations are the most common type of congenital vascular malformations. Over the last two decades management of these lesions has significantly improved, predominantly due to the introduction and implementation of multidisciplinary team concept as well as improvement in diagnostic and treatment modalities. Relatively recently genetic studies are providing more insights into underlying pathophysiological mechanisms responsible for the development and progression of venous malformations and pharmacotherapy is becoming extensively evaluated for safety and efficacy in the treatment of these often challenging vascular lesions.

Sirolimus in the treatment of kaposiform lymphangiomatosis

BACKGROUND

Kaposiform lymphangiomatosis (KLA), which is a new subtype of generalized lymphatic anomaly, is a rare disease with a poor prognosis. Currently, there is no standard treatment due to the poor understanding of KLA. Sirolimus, which is an inhibitor of mammalian target of rapamycin, has been shown to have promising potential in the treatment of complicated vascular anomalies. The aim of this study was to introduce the use of sirolimus for the treatment of KLA and to highlight the challenges of managing this refractory disease.

RESULTS

We reported seven patients with KLA who received sirolimus therapy in our center. Combined with previously reported cases, 58.3% achieved a partial response, 25.0% had stable disease, and 16.7% experienced disease progression. No severe sirolimus-related adverse events occurred during treatment.

CONCLUSIONS

This study suggests that sirolimus is currently an option for the treatment of KLA, and it is hoped that more specific therapies will be developed in the future. Rapid advances in basic science and clinical practice may facilitate the development of important new treatments for KLA.

Long-term outcomes of pediatric and young adult patients receiving radiotherapy for nonmalignant vascular anomalies

BACKGROUND

Nonmalignant vascular anomalies (VA) comprise a heterogeneous spectrum of conditions characterized by aberrant growth or development of blood and/or lymphatic vessels and can cause significant morbidity. Little is known about outcomes after radiotherapy in pediatric and young adult patients with nonmalignant VA.

METHODS

Thirty patients who were diagnosed with nonmalignant VA and treated with radiotherapy prior to 2017 and before the age of 30 were identified. Clinical and treatment characteristics and outcomes were recorded.

RESULTS

Median age at first radiotherapy was 15 years (range 0.02-27). Median follow-up from completion of first radiotherapy was 9.8 years (range 0.02-67.4). Lymphatic malformations (33%), kaposiform hemangioendothelioma (17%), and venous malformations (17%) were the most common diagnoses. The most common indication for first radiotherapy was progression despite standard therapy and/or urgent palliation for symptoms (57%). After first radiotherapy, 14 patients (47%) had a complete response or partial response, defined as decrease in size of treated lesion or symptomatic improvement. After first radiotherapy, 27 (90%) required additional treatment for progression or recurrence. Long-term complications included telangiectasias, fibrosis, xerophthalmia, radiation pneumonitis, ovarian failure, and central hypothyroidism. No patient developed secondary malignancies. At last follow-up, three patients (10%) were without evidence of disease, 26 (87%) with disease, and one died of complications (3.3%).

CONCLUSIONS

A small group of pediatric and young adult patients with nonmalignant, high-risk VA experienced clinical benefit from radiotherapy with expected toxicity; however, most experienced progression. Prospective studies are needed to characterize indications for radiotherapy in VA refractory to medical therapy, including targeted inhibitors.

Off-Label Use and Safety of Drug Use in Vascular Anomalies

BACKGROUND

Off-label drug use is associated with an increased risk of adverse drug reactions. It is common in pediatrics and in rare diseases, which are two characteristics applying to vascular anomalies (VA).

OBJECTIVES

The aim of this work was to quantify off-label drug use in VA and assess its safety.

METHODS

A review was conducted to extract a list of drugs used in VA management. A drug was considered to have significant safety concerns if a black box warning was present or if a serious adverse drug reaction (SADR) was reported in at least 1% of the patients (SADR is defined as a noxious and unintended response to a drug that occurs at any dose and results in hospitalization, prolongation of existing hospitalization, congenital malformation, persistent or significant disability or incapacity, life-threatening condition, or death). The labelling status and safety of each drug was assessed based on the product monograph, Micromedex, and the FDA data.

RESULTS

We found that 98.9% of the inventoried drugs were used off-label or unlicensed for VA management. Only the oral solution of propranolol hydrochloride (Hemangeol®) for the treatment of infantile hemangiomas is approved. Significant safety issues concerned 73% of the drugs and were more frequent among systemic than locally delivered drugs.

CONCLUSIONS

Off-label drug use in VA is the rule and not the exception. Significant safety concerns are common. It is necessary to carefully weigh risk and benefits for every patient when using systemic and local treatments carrying safety concerns. Patients should be openly informed and involved in the decision-making process.

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

OBJECTIVE

Lymphatic malformations (LM) are common congenital vascular lesions, most often diagnosed at birth. They deform local anatomy and can be life-threatening if they compress the aerodigestive tract or other vital structures. Significant progress has been made in the treatment of LMs in the past 20 years. We conducted a systematic review of the literature on the management of LMs.

METHODS

On September 21, 2020, we searched PubMed/MEDLINE for studies published from 2000 to 2020 reporting outcomes of invasive and pharmacologic treatment of LMs.

RESULTS

A total of 251 studies met the eligibility criteria. Surgery has continued to be a mainstay in the management of LMs, especially in the treatment of microcystic and mixed lesions. Sclerotherapy has emerged as a first-line treatment of macrocystic LMs and as an adjunctive therapy used in combination with surgery for other lesions. Sirolimus, a strong inhibitor of mTOR (mechanistic target of rapamycin), has shown tremendous promise in the treatment of LMs, as both an oral and a topical agent. Recent investigations have shown the potential of targeted small molecule modulators of cellular pathways in the treatment of LMs.

CONCLUSIONS

Multiple invasive and pharmacologic therapies have been shown to be effective in the treatment of LMs. Future research should focus on rigorous, prospective comparisons of these treatment modalities.

Recent Progress in Lymphangioma

Lymphangioma is a common type of congenital vascular disease in children with a broad spectrum of clinical manifestations. The current classification of lymphangioma by International Society for the Study of Vascular Anomalies is largely based on the clinical manifestations and complications and is not sufficient for selection of therapeutic strategies and prognosis prediction. The clinical management and outcome of lymphangioma largely depend on the clinical classification and the location of the disease, ranging from spontaneous regression with no treatment to severe sequelae even with comprehensive treatment. Recently, rapid progression has been made toward elucidating the molecular pathology of lymphangioma and the development of treatments. Several signaling pathways have been revealed to be involved in the progression and development of lymphangioma, and specific inhibitors targeting these pathways have been investigated for clinical applications and clinical trials. Some drugs already currently in clinical use for other diseases were found to be effective for lymphangioma, although the mechanisms underlying the anti-tumor effects remain unclear. Molecular classification based on molecular pathology and investigation of the molecular mechanisms of current clinical drugs is the next step toward developing more effective individualized treatment of children with lymphangioma with reduced side effects.

Venous malformations: Coagulopathy control and treatment methods

Venous malformations (VMs) are ectatic channels which arise as a result of vascular dysmorphogenesis, commonly caused by activating mutations in the endothelial tyrosine kinase receptor (TIE2)/phosphatidylinositol 3-kinase (PI3Kinase) pathway. With a prevalence of 1% in the general population, and a diverse clinical presentation depending on site, size and tissue involvement, their treatment requires a personalised and multidisciplinary approach. Larger lesions are complicated by local intravascular coagulopathy (LIC) causing haemorrhagic and/or thrombotic complications which can progress to disseminated intravascular coagulopathy (DIC).

METHODS

We performed a literature review using a PubMed® search and identified 15 articles to include. References of these texts were examined to further expand the literature review.Principle findings: Several treatment options have been explored, including compression, sclerotherapy, laser therapy, cryoablation and surgery in addition to the management of LIC with low-molecular-weight-heparin (LMWH) and other anticoagulants. Targeted molecular therapies acting on the phosphatidylinositol 3-kinase (PI3Kinase)/Protein Kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway are newly emerging.

CONCLUSION

Despite a wealth of literature, larger, multi-centric, randomised and prospective trails are required to offer further clarification on the therapeutic management of coagulopathy control and to provide symptomatic benefit to patients with VMs. There should be efforts to provide long term follow up and to use standardised risk stratification tools and quality of life (QOL) questionnaires to aid comparison of agents and treatment protocols.

Coagulation issues in vascular anomalies

Vascular anomalies, comprised of vascular tumors and malformations, are frequently associated with coagulopathy. Recognition of and familiarity with these vascular anomaly-associated hematologic abnormalities prior to surgery or interventional procedures is essential for pre-operative pre-operative planning. Complicated coagulopathies present within the framework of either Kasabach-Merritt phenomenon (KMP) or localized intravascular coagulopathy (LIC), and their management benefits from the expertise of a hematologist for optimal intra- and peri‑operative care. Furthermore, with the recent broadening of understanding of vascular anomalies and the addition of new classification sub-groups, distinctions of these two classic coagulopathy phenotypes have been recognized. This review summarizes the main features of these coagulopathies, described according to their vascular anomaly type, highlighting clinical aspects relevant to surgical management.

New and Emerging Targeted Therapies for Vascular Malformations

Vascular malformations are inborn errors of vascular morphogenesis and consist of localized networks of abnormal blood and/or lymphatic vessels with weak endothelial cell proliferation. They have historically been managed by surgery and sclerotherapy. Extensive insight into the genetic origin and molecular mechanism of development has been accumulated over the last 20 years. Since the discovery of the first somatic mutations in a vascular anomaly 10 years ago, it is now recognized that they are perhaps all caused by inherited or somatic mutations in genes that hyperactivate two major intracellular signaling pathways: the RAS/MAPK/ERK and/or the phosphatidylinositol 3 kinase (PIK3)/protein kinase B/mammalian target of rapamycin (mTOR) pathway. Several targeted molecular inhibitors of these pathways have been developed, mostly for the treatment of cancers that harbor mutations in the same pathways. The mTOR inhibitor sirolimus is the most studied compound for the treatment of venous, lymphatic, and complex malformations. Disease responses of vascular malformations to sirolimus have now been reported in several studies in terms of clinical changes, quality of life, functional and radiological outcomes, and safety. Other targeted treatment strategies, such as the PIK3CA inhibitor alpelisib for PIK3CA-mutated vascular malformations, are also emerging. Repurposing of cancer drugs has become a major focus in this rapidly evolving field.

Venous malformations

Venous malformations include a spectrum of slow-flow malformations that together are the most common forms of vascular anomalies. Care of these patients requires a multi-disciplinary approach. Goals of care are to ameliorate symptoms and to preserve function. Use of therapeutic compression garments remains the mainstay of therapy. There are new and promising therapies over the last few years that will be invaluable tools for optimal care of this complex patient population. Advances in medical therapy through inhibition of the mTOR/PI3K/AKT pathway with Sirolimus and more proximal targeted drugs along with advances in sclerotherapy techniques are promising for the long-term improvement and amelioration of symptoms in patients with venous malformations.

Lymphatic malformations

Lymphatic malformations are low-flow vascular malformations that arise due to errors in vascular development. Lymphatic malformations are benign and usually noted at birth or in the first few years of life. Lymphatic mass lesions are composed of varying size of cysts; this article focuses on discussion of cystic lymphatic malformations. Lymphatic malformations can occur throughout the body especially in lymphatic rich areas such as the cervical and axillary locations as well as the groin, trunk, retroperitoneum, extremities, abdominal or thoracic cavities. Treatment options vary based upon size of cysts and location. A multimodal and interdisciplinary approach is essential to care for patients with lymphatic malformations. Management options include observation, pharmacotherapy, sclerotherapy, and surgical procedures.

The Impact of Adjuvant Sirolimus Therapy in the Surgical Management of Scrotal Slow-Flow Vascular Malformations

OBJECTIVE

To describe the effects of oral sirolimus administered before and after surgical resection of slow-flow vascular malformations of the scrotum in pediatric patients.

METHODS

Retrospective review of 3 patients presenting with complex lymphatic-venous malformations of the scrotum who received adjuvant oral sirolimus 3 months before and 3 months after surgical resection. Demographic data, clinical course, imaging findings, and management strategies were reviewed for each patient.

RESULTS

In each of the 3 patients, there was a significant volume reduction of the lesion within the 3 months after initial dose of sirolimus. Scarce lymphatic leakage during and after surgery was reported, associated with an adequate wound healing. Two years after the last postsurgical dose of sirolimus, all patients remain asymptomatic without any lymphatic leakage or lesion recurrence.

CONCLUSION

Combined lymphatic-venous vascular malformations of the male genitalia are rare but associated with high morbidity and challenging treatment options. Pre- and postsurgical adjuvant treatment with oral sirolimus seems to be a promising therapeutic option that provides reduction of the lesion size before surgery and improvement of postsurgical recovery and wound healing.

Immunologic Effects of Sirolimus in Patients With Vascular Anomalies

Emerging data have suggested that sirolimus may be a treatment option for complicated vascular anomalies (VAs). The present study aimed to investigate the immunologic effects of sirolimus treatment for 6 months in patients with VAs. Blood samples obtained from the patients enrolled in 2 multicenter studies to investigate the efficacy of sirolimus for VAs before and after sirolimus treatment for 6 months were used. Data for total white blood cell count, absolute lymphocyte count, serum immunoglobulins (Igs) levels (IgG, IgA, IgM), lymphocyte proliferation assays with mitogens including phytohemagglutinin and concanavalin A, and flow cytometric analysis of lymphocyte subsets were evaluated. A total of 18 patients with VAs receiving sirolimus treatment were included in the study. Comparisons of white blood cell, absolute lymphocyte count, IgG, IgA, IgM, and reaction rates of phytohemagglutinin and concanavalin A revealed no significant differences before and after treatment. No significant differences were observed in the absolute counts of lymphocyte subtypes before and after treatment, except for regulatory T-cell counts, which were significantly decreased after treatment. Severe infections were not observed during sirolimus treatment. The immunologic parameters assessed in the present study were hardly affected by sirolimus treatment for 6 months in patients with VAs.

Complex Lymphatic Anomalies and Therapeutic Options

Complex lymphatic anomalies include a variety of disorders with overlapping clinical, histological and imaging features. The often-confusing nomenclature used for lymphatic anomalies limits timely diagnosis and treatment. The updated 2018 classification of the International Society for the Study of Vascular Anomalies divides lymphatic anomalies into several subsets.¹ Newer imaging techniques including intranodal and magnetic resonance lymphangiography have improved our understanding of anatomy and function of the lymphatic system. Advances in medical, interventional, and surgical treatments have opened a realm of new therapeutic options for patients with complex lymphatic disorders.

Risk factors for hemorrhage of brain arteriovenous malformation

Patients with brain arteriovenous malformation (bAVM) are at risk of intracranial hemorrhage (ICH). Overall, bAVM accounts for 25% of hemorrhagic strokes in adults <50 years of age. The treatment of unruptured bAVMs has become controversial, because the natural history of these patients may be less morbid than invasive therapies. Available treatments include observation, surgical resection, endovascular embolization, stereotactic radiosurgery, or combination thereof. Knowing the risk factors for bAVM hemorrhage is crucial for selecting appropriate therapeutic strategies. In this review, we discussed several biological risk factors, which may contribute to bAVM hemorrhage.