Sirolimus for the Treatment of a Massive Capillary-Lymphatico-Venous Malformation: A Case Report

Targeted therapies for vascular malformations

Targeted medical therapies for the treatment of vascular malformations is an exciting and evolving area of research. As the identification of specific causative genetic mutations involved in vascular malformations becomes more accessible and inexpensive, the development of targeted therapies to address these genetic anomalies becomes all the more enticing. It is an excellent example of the potential of translational research where basic science discoveries are translated to clinical practise from 'bench to bedside'. In this mini-review we aim to synopsise some of the recent studies published in this area with specific focus on the paediatric population. We also aim to highlight the growing demand for future research in the field to elucidate further the optimum duration of treatments, strategies for discontinuation, potential for combination of therapies and the effects of prolonged use of these medications.

Response to sirolimus in capillary lymphatic venous malformations and associated syndromes: Impact on symptomatology, quality of life, and radiographic response

BACKGROUND

Capillary lymphatic venous malformations (CLVM) and associated syndromes, including Klippel-Trenaunay syndrome (KTS) and congenital lipomatous overgrowth, vascular malformation, epidermal nevi, skeletal, and spinal syndrome (CLOVES), are underrecognized disorders associated with high morbidity from chronic pain, recurrent infections, bleeding, and clotting complications. The rarity of these disorders and heterogeneity of clinical presentations make large-scale randomized clinical drug trials challenging. Identification of PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha [gene]) mutations in CLVM has made targeted medications, such as sirolimus, attractive treatment options. The aim of this study was to investigate the safety and efficacy of sirolimus therapy in CLVM.

PROCEDURE

A combined prospective and retrospective cohort of pediatric and young adult patients with CLVM treated with sirolimus was evaluated for disease response, including symptom improvement, quality of life (QOL), and radiologic response. Sirolimus dosing regimens and toxicities were also assessed.

RESULTS

Twenty-nine patients with CLVM, including KTS and CLOVES, were included. Ninety-three percent of patients reported improved QOL, and 86% had improvement in at least one symptom. Most significantly, improvement was noted in 100% of patients with bleeding and 89% with thrombotic complications with corresponding decreases in mean D-dimer (p = .008) and increases in mean fibrinogen (p = .016). No patients had progressive disease on sirolimus. Most common side effects included neutropenia, lymphopenia, infection, and aphthous ulcers/stomatitis. No toxicities were life-threatening, and none required long-term discontinuation of sirolimus.

CONCLUSION

Sirolimus appears to be effective at reducing complications and improving QOL in patients with CLVM and associated syndromes. In this patient cohort, sirolimus was well tolerated and resulted in few treatment-related toxicities.

Lymphatic malformations in children: retrospective review of surgical and interventional management

PURPOSE

Lymphatic malformations (LMs) are classified as macrocystic, microcystic or mixed. Treatment depends on their characteristics: surgery, sclerotherapy, both combined, systemic treatment or observation. This study aims to analyze the surgical and interventional management of LMs in children over the last two decades in our university hospital.

METHODS

Management of children born with LMs between 2000 and 2019 was reviewed. Parameters collected were: malformation characteristics, type of treatment, symptoms, imaging, timing of diagnosis and first treatment, number of interventions, recovery rate, complications and length of stay.

RESULTS

Files of 48 children were reviewed: 27 with macrocystic and 21 with microcystic LMs. There was no statistically significant difference in type of treatment except for combined treatment, more performed in microcystic LMs (p = 0.04). Symptoms, imaging, timing of diagnosis and first treatment, number of interventions and complications were not statistically significant. Overall, the number of surgeries was lower than sclerotherapies (p = 0.04). Recovery rate after surgery was higher in macrocystic LMs (p = 0.01). Complications and length of stay were not statistically significant.

CONCLUSION

A good rate of recovery was observed when surgery was performed, with no significant increase in complications and length of stay. A prospective study will be determinant to create a decisional algorithm for children with LMs.

No association of sirolimus with wound complications in children with vascular anomalies

INTRODUCTION

Sirolimus has demonstrated effectiveness as a treatment option for several types of vascular anomalies; however, it has a potential side effect of delayed surgical wound healing. The purpose of this study was to evaluate the association of sirolimus with postoperative complications in the pediatric vascular anomaly population.

METHODS

A retrospective cohort study was performed for children with a vascular anomaly who underwent excision or debulking of the anomaly from 2015 to 2020. Patient demographics, vascular anomaly characteristics, operative variables, sirolimus dosing information, and perioperative outcomes were collected. Univariate analysis was performed to compare outcomes based on the administration of sirolimus.

RESULTS

Forty-seven patients with vascular anomalies underwent 57 surgical procedures (36 without perioperative sirolimus, 21 with perioperative sirolimus). The median age at the time of surgery was seven years (IQR 1.7-14.0). The most common anomalies were lymphatic and venolymphatic malformations. Of the patients administered perioperative sirolimus, the median preoperative and postoperative sirolimus levels were comparable (preoperative 6.9 ng/mL (IQR 4.9-10.1), postoperative 6.5 ng/mL (IQR 4.7-9.4)). The rate of postoperative complications (sirolimus 19%, without sirolimus 11%; p = 0.45) and wound complications (sirolimus 14%, without sirolimus 6%; p = 0.26) were comparable between the cohorts.

CONCLUSION

Our results suggest sirolimus may not significantly increase perioperative complication rates in pediatric patients undergoing resection of their vascular anomaly.

LEVEL OF EVIDENCE

Level III.

Institutional Management of Abdominal Lymphatic Malformations: Evolution of Treatment Over a Decade

INTRODUCTION

Abdominal lymphatic malformations (LM) have been historically managed with surgical resection; however, sclerotherapy and sirolimus have emerged as effective therapies. The purpose of our study is to evaluate our institutional change in management and outcomes for abdominal LM over the past decade.

METHODS

A retrospective cohort study was performed for all children with an abdominal LM managed at our multidisciplinary Vascular Anomalies Center from 2011 to 2020. Patient demographics, symptoms, treatment, treatment response, and complications were analyzed with descriptive statistics.

RESULTS

Twenty-nine patients with abdominal LM were identified with a median age at treatment of 6 y (interquartile range 3-14). A majority of lesions were identified as macrocystic (n = 18, 62%). The most common intervention was surgery alone (n = 14, 48%) followed by sirolimus alone (n = 4, 14%), and sclerotherapy + sirolimus (n = 4, 14%). Five patients were observed due to lack of symptoms at presentation. Prior to 2017, 91% (10/11) of LM were treated with surgery alone. Following 2017, only 31% (4/13) were treated with surgery alone. Sixty-seven percent (16/24) of treated patients had >95% reduction in LM maximum diameter. A majority of patients (23/24) who received treatment had improvement or resolution of symptoms at median 9-mo follow-up. Only three patients had post-treatment complications, including a drain site infection, small bowel obstruction, and an aspiration event. Complications only occurred after sclerotherapy sessions.

CONCLUSIONS

Over the study period, our institution has transitioned to initial management of symptomatic abdominal LM with sclerotherapy and/or sirolimus with almost all treated patients having excellent or satisfactory treatment response. Post-treatment complications were rare.

How we approach the use of sirolimus and new agents: Medical therapy to treat vascular anomalies

Vascular anomalies (VAs) are a heterogeneous group of primarily congenital tumors and malformations. The International Society for the Study of Vascular Anomalies (ISSVA) has developed a standard classification of these disorders, creating a uniform approach to their diagnosis. Recent discoveries evaluating the genetic causes of VAs have revealed that they are due to mutations in cancer pathways, including the PI3K/AKT/mTOR and RAS/MAPK/MEK pathways. These discoveries have led to improved phenotype-genotype correlation and have expanded medical therapy for this group of unique disorders.

Complex lymphatic malformations in pediatrics: a review of treatment options

INTRODUCTION

Lymphatic malformations (LMs) are low-flow lesions resulting from abnormalities in the development of lymphatics. The management of these lesions is complex and involve the collaboration of many specialties. The purpose of this review is to summarize current knowledge regarding the different therapeutic options used in complex lymphatic malformations, analyzing their indications, efficacy and complications.

EVIDENCE ACQUISITION

A search was made using the algorithm: "(lymphatic abnormality OR lymphatic malformation OR lymphangioma OR cystic hygroma) AND (extensive OR giant OR complex) AND (therapeutics OR treatment) AND (child OR children)". Of the 120 articles found, 53 were included.

EVIDENCE SYNTHESIS

Historically, surgery was the treatment of choice for this type of lesions. However, excision was often incomplete, associated with high rates of recurrence and severe complications. The use of sclerotherapy emerged as a minimal invasive option appropriate in selected cases as a single or adjuvant therapy. Inhibitors of the mammalian target of rapamycin, such as sirolimus, now play a central role in the treatment of complex malformations resistant to sclerotherapy, recurrent after surgery or more extensive malformations that affect vital structures. Other therapeutic options as sildenafil and laser ablation are also recognized as effective in selected cases.

CONCLUSIONS

Looking through the literature over the last decade authors realize that surgery had gradually been replaced by less invasive options such as sirolimus with or without adjuvant sclerotherapy. In conclusion, each treatment option seems to have its own indications and characteristics, which must be considered in therapeutic decision and individualized for each patient.

Indications and Limitations of Sirolimus in the Treatment of Vascular Anomalies-Insights From a Retrospective Case Series

BACKGROUND

Despite recent developments, the role of sirolimus in the heterogeneous spectrum of vascular anomalies is yet to be defined, in terms of indication, dosage, and therapy duration, recognizing both its potential and limitations.

METHODS

We retrospectively analyzed 16 children with vascular anomalies treated with sirolimus in two pediatric centers between 2014 and 2020 [male: n = 7, the median age at diagnosis: 4.6 months (range, 0-281.4)]. In addition, repetitive volumetric analyses of the vascular anomalies were performed when possible (11 cases).

RESULTS

Ten patients were diagnosed with vascular malformations and 6 with vascular tumors. The mean therapy duration was 27.2 months (range, 3.5-65). The mean sirolimus level was 8.52 ng/ml (range, 5.38-12.88). All patients except one with central conducting lymphatic anomaly responded to sirolimus, with the most noticeable volume reduction in the first 4-6 months. Additional administration of vincristine was needed in five patients with kaposiform hemangioendothelioma and yielded a response, even in cases, refractory to sirolimus monotherapy. As a single agent, sirolimus led to impressive improvement in a patient with another vascular tumor-advanced epithelioid hemangioendothelioma. Complicated vascular malformations required long-term sirolimus therapy. Side effects of sirolimus included mucositis and laboratory abnormalities. No major infectious episodes were recorded. An infant with COVID-19, diagnosed while on sirolimus therapy, presented with a mild course.

CONCLUSION

In the current series, we reported limitations of sirolimus as monotherapy, addressing the need to redefine its indications, and explore combination regimens and multimodal treatment strategies. Tools for objective evaluation of response trends over time could serve as a basis for the establishment of future therapeutic algorithms.

The Use of Sirolimus for Treatment of Orbital Lymphatic Malformations: A Systematic Review

PURPOSE

Orbital lymphatic malformations are rare congenital choristomas associated with pain, proptosis, exposure keratopathy, and vision loss. Current treatments of surgery, drainage, and sclerotherapy may have adverse effects including risk of damage to surrounding structures, swelling, and malformation persistence or recrudescence. Sirolimus, which inhibits mammalian target of rapamycin, a regulator of cell growth and vascular endothelial growth factor expression, has successfully treated systemic vascular malformations. However, its efficacy and safety have not yet been well established for orbital lymphatic malformations.

METHODS

Systematic review and analysis of relevant published literature were performed. PubMed, Embase, and World of Science searches were conducted for studies involving sirolimus treatment of orbital lymphatic malformations through July 2019.

RESULTS

Nine case series and reports with 10 total patients who received sirolimus for treatment of orbital lymphatic malformations were included. The age at sirolimus initiation ranged from 1 week to 23 years. The malformation was lymphatic in 6 patients, lymphaticovenous in 3 patients, and lymphatic-arteriovenous in 1 patient. Six patients underwent ineffective prior therapy including sclerotherapy, surgery, or medical therapy. Initial sirolimus dosage ranged from 0.05 mg/kg twice a day to 1 mg twice a day, and duration ranged from 6 months to 53 months. Seven patients had partial response, and 3 patients, all of whom had a microcystic malformation component, experienced complete response. Adverse effects included mild reversible leukopenia, hypertriglyceridemia, hypercholesterolemia, and transaminitis with adverse effects denied or not specified for 6 patients.

CONCLUSIONS

Sirolimus may be a safe and effective treatment for orbital lymphatic malformations, especially microcystic 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.

Cell Populations Expressing Stemness-Associated Markers in Vascular Anomalies

Treatment of vascular anomalies (VAs) is mostly empirical and, in many instances unsatisfactory, as the pathogeneses of these heterogeneous conditions remain largely unknown. There is emerging evidence of the presence of cell populations expressing stemness-associated markers within many types of vascular tumors and vascular malformations. The presence of these populations in VAs is supported, in part, by the observed clinical effect of the mTOR inhibitor, sirolimus, that regulates differentiation of embryonic stem cells (ESCs). The discovery of the central role of the renin-angiotensin system (RAS) in regulating stem cells in infantile hemangioma (IH) provides a plausible explanation for its spontaneous and accelerated involution induced by β-blockers and ACE inhibitors. Recent work on targeting IH stem cells by inhibiting the transcription factor SOX18 using the stereoisomer R(+) propranolol, independent of β-adrenergic blockade, opens up exciting opportunities for novel treatment of IH without the β-adrenergic blockade-related side effects. Gene mutations have been identified in several VAs, involving mainly the PI3K/AKT/mTOR and/or the Ras/RAF/MEK/ERK pathways. Existing cancer therapies that target these pathways engenders the exciting possibility of repurposing these agents for challenging VAs, with early results demonstrating clinical efficacy. However, there are several shortcomings with this approach, including the treatment cost, side effects, emergence of treatment resistance and unknown long-term effects in young patients. The presence of populations expressing stemness-associated markers, including transcription factors involved in the generation of induced pluripotent stem cells (iPSCs), in different types of VAs, suggests the possible role of stem cell pathways in their pathogenesis. Components of the RAS are expressed by cell populations expressing stemness-associated markers in different types of VAs. The gene mutations affecting the PI3K/AKT/mTOR and/or the Ras/RAF/MEK/ERK pathways interact with different components of the RAS, which may influence cell populations expressing stemness-associated markers within VAs. The potential of targeting these populations by manipulating the RAS using repurposed, low-cost and commonly available oral medications, warrants further investigation. This review presents the accumulating evidence demonstrating the presence of stemness-associated markers in VAs, their expression of the RAS, and their interaction with gene mutations affecting the PI3K/AKT/mTOR and/or the Ras/RAF/MEK/ERK pathways, in the pathogenesis of VAs.

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.

Imaging assessment and treatment of soft-tissue venous malformations: Retrospective case series study of 126 cases

Venous malformations (VMs) are common slow-flow vascular malformations, which affect almost anywhere of the body. From January 2010 to October 2019, 126 patients with VMs who had complete imaging and follow-up data were enrolled into this study, including 75 males. The initial treatment age ranged from 5 to 72 years. The role of imaging results on the choice of treatment measures and the application were summarized. In this study, we retrospectively analyzed the imaging examinations, treatment measures, and follow-up results of the patients with VMs in our clinic. In this series, imaging examinations included ultrasound, magnetic resonance imaging, computed tomography (CT) scan and enhanced scan, percutaneous sinus angiography and three-dimensional CT imaging, plain film, CT venography, CT angiography, and digital subtraction angiography. Treatment measures included surgical excision (n = 20), sclerotherapy (n = 86, including absolute ethanol [n = 75], polidocanol [n = 8], and pingyangmycin [n = 3]), and combination treatment with intralesional copper wire retention and sclerotherapy(n = 20). After treatment, most of the lesions shrunk obviously or disappeared, and the symptoms were largely relieved. Comprehensive and accurate imaging assessment of VMs is necessary for selecting appropriate treatment. Individual strategy and sequential treatment can achieve effective results and avoid potential complications.

Benign vascular anomalies: A transition from morphological to etiological classification

The International Society for the Study of Vascular Anomalies (ISSVA) devised a multidisciplinary etiopathogenesis based approach to classify benign vascular anomalies into tumors and malformations. This classification scheme has major therapeutic and prognostic implications as treatment modalities differ for both the categories. Inappropriate usage of the term "hemangioma" for etiopathogenetically distinct entities is commonly seen in clinical practice leading to delivery of incorrect treatment to the patients. We aimed to study the histomorphological and immunohistochemical features of benign vascular anomalies for their precise histopathological classification. A total of 48 cases diagnosed over a period of 3.5 years were reviewed and reclassified into vascular tumors and malformations based on ISSVA classification and prototypical histopathological features. Biopsies were reviewed based on 5 histopathological criteria viz. endothelial morphology, mitotic activity, intralesional nerve bundles, intralesional inflammation, and prominent vessel type. A panel of GLUT-1, WT-1, and Ki-67 was performed in each case. Seven cases of infantile hemangioma, 4 cases each of non-involuting congenital hemangioma and pyogenic granuloma, and 33 cases of vascular malformations were diagnosed. Endothelial cell morphology (p < 0.001), mitotic activity (p < 0.001), and intralesional nerve bundles (p < 0.001) were found to be statistically significant in differentiating hemangioma from malformations. GLUT-1 (p < 0.001) and Ki-67 labeling index (p < 0.001) were useful to distinguish infantile hemangioma from vascular malformations. To conclude, the ISSVA classification of benign vascular anomalies can be reliably done on histopathology. However, every case must be interpreted in the light of clinical and radiological features.

Propranolol for the Treatment of Lymphatic Malformations in a Neonate - A Case Report and Review of Literature

Lymphatic malformations in neonates often manifest as a chylothorax, and although rare, morbidity and mortality can be significant. First-line treatment with medium-chain triglyceride-enriched formulas, or enteric rest with total parenteral nutrition, are not always successful. We describe the case of a premature neonate with trisomy 21 who presented with bilateral pleural effusions and a pericardial effusion that worsened with the initiation of enteral nutrition. Clinical improvement was not seen until the initiation of treatment with oral propranolol at a maximum dosage of 0.5 mg/kg/day divided every 8 hours with extubation 8 days after propranolol initiation. Two case reports have described the use of propranolol in similar patients receiving 2 mg/kg/day; however, our experience is the first to report treatment success at a much lower dose. A review of the literature for alternative medication treatments uncovered numerous case reports and series documenting variable results with incongruent definitions of treatment success in a diverse patient population. The rarity of this disease state makes accrual of patients difficult and more robust treatment data unlikely. Therefore, selection of the optimal adjunctive treatment must be based on individual patient and disease state characteristics as well as safety and efficacy profile of the medication.

Efficacy of systemic sirolimus in the treatment of generalized lymphatic anomaly and Gorham-Stout disease

BACKGROUND

Generalized lymphatic anomaly (GLA) and Gorham-Stout disease (GSD) are rare complicated lymphatic malformations that occur in multiple body sites and are associated with significant morbidity and mortality. Treatment options have been limited, and conventional medical therapies have been generally ineffective. Emerging data suggest a role for sirolimus as a treatment option for complex lymphatic anomalies.

PROCEDURE

Disease response was evaluated by radiologic imaging, quality of life (QOL), and clinical status assessments in children and young adults with GLA and GSD from a multicenter systematic retrospective review of patients treated with oral sirolimus and the prospective phase 2 clinical trial assessing the efficacy and safety of sirolimus in complicated vascular anomalies (NCT00975819). Sirolimus dosing regimens and toxicities were also assessed.

RESULTS

Eighteen children and young adults with GLA (n = 13) or GSD (n = 5) received oral sirolimus. Fifteen patients (83%) had improvement in one or more aspects of their disease (QOL 78%, clinical status 72%, imaging 28%). No patients with bone involvement had progression of bone disease, and the majority had symptom or functional improvement on sirolimus. Improvement of pleural and pericardial effusion(s) occurred in 72% and 50% of affected patients; no effusions worsened on treatment.

CONCLUSIONS

Sirolimus appears effective at stabilizing or reducing signs/symptoms of disease in patients with GLA and GSD. Functional impairment and/or QOL improved in the majority of individuals with GLA and GSD with sirolimus treatment.

Molecular changes associated with vascular malformations

Vascular anomalies are typically classified into two major categories, vascular tumors and vascular malformations. Most vascular malformations are caused sporadically by somatic mosaic gene mutations, and genetic analyses have advanced our understanding of the biomolecular mechanisms involved in their pathogenesis. Culprit gene mutations typically involve two major signaling pathways; the RAS/MAPK/ERK pathway is typically involved in fast-flow arteriovenous malformations, whereas the PI3K/AKT/mTOR pathway is typically mutated in slow-flow venous and lymphatic malformations. These findings suggest new therapeutic approaches to vascular malformations, focusing on targeting the etiologic mutated pathways. This review summarizes the currently available literature reflecting the updated International Society for Study of Vascular Anomalies classification system with emphasis on potential therapeutic targets that will provide vascular surgeons with an updated perspective on the etiologic basis of vascular malformations, allowing improved multidisciplinary collaboration.

Overgrowth syndrome in neonates: a rare case series with a review of the literature

We present here two-term neonates presenting with right lower limb hypertrophy, a port-wine stain, acral abnormalities and clubfeet. These neonates had overlapping features of Klippel Trenaunay syndrome and congenital lipomatous overgrowth, vascular malformation, epidermal nevi and scoliosis/skeletal abnormalities. Such overgrowth syndrome has not been previously described in the literature. Both the neonates are doing well and are under regular follow-up.

Treatment of Lymphatic Malformations with the mTOR Inhibitor Sirolimus: A Systematic Review

BACKGROUND

Extensive lymphatic malformations are low-flow vascular malformations that can cause devastating complications. Treatment of these malformations is challenging. This systematic review presents current use of sirolimus in patients with extensive lymphatic malformations.

METHODS

MEDLINE and Google scholar search was conducted for studies on sirolimus treatment of lymphatic malformations up to July 2017. Search items included "lymphatic malformation," "lymphangioma," "cystic hygroma," "vascular malformation," "low-flow malformation," "sirolimus," "rapamycin," and "mTOR inhibitor."

RESULTS

Twenty studies, including 71 patients receiving sirolimus, were included into this review. Forty-five patients had lymphatic malformations, eight patients venolymphatic malformations, and 19 patients capillary-lymphatico-venous malformations. Sirolimus led to a partial remission of disease in 60 patients, three patients had a progressive disease, and the outcome of eight patients was not reported. Dosing, target trough level, and duration of treatment differed between the studies. Common adverse effects were hyperlipidemia and neutropenia.

CONCLUSIONS

Available literature indicated that sirolimus therapy might be effective for lymphatic malformations. However, further randomized controlled studies are required to analyze the efficacy and long-term adverse events and to clarify the potential role for sirolimus in the management of lymphatic malformations.

A large retroperitoneal lymphatic malformation successfully treated with traditional Japanese Kampo medicine in combination with surgery

BACKGROUND

Current treatment options for lymphatic malformations (LMs) are multimodal. Recently, the effectiveness of treating LMs with Eppikajyutsuto (TJ-28) has been reported. TJ-28 is a kind of oral herbal medicine classified as the traditional Japanese Kampo medicine.

CASE PRESENTATION

A 12-year-old girl was admitted to our hospital for intermittent upper abdominal pain. Radiological examinations revealed a large (9.5 × 5.8 × 10.0 cm) retroperitoneal LM, which was suspected to adhering and stretching both pancreas head and duodenum. The large retroperitoneal tumor resection might induce involving complications because of the size and the location. Therefore, we used TJ-28 in order to diminish the tumor size before surgery. The patient received oral doses of 7.5 g/day (2.5 g × 3 times/day) of TJ-28. Six months after the medication, the tumor decreased markedly to 3.5 × 1.5 × 1.2 cm in size. Thereafter, the mass was sub-totally resected (95%) via a 3 cm trans-umbilical incision without any surgical complications.

CONCLUSIONS

We reported a case of successfully treated retroperitoneal LM with the combination treatment of TJ-28 and surgery. Based on our experience, this TJ-28 treatment option may be very useful in treating cases of LMs having surgical difficulties because of size and/or location.

Advances in the Medical Management of Vascular Anomalies

Vascular anomalies comprise a spectrum of diseases that are broadly classified as tumors and malformations. Diagnosis is often challenging, given a wide range of clinical presentations with overlapping signs and symptoms. Accurate diagnosis is critical to determine prognosis and to generate a management plan, which frequently involves multiple subspecialists during different phases of treatment. An updated classification system provides structure and clear, consistent terminology, allowing for improved diagnosis, provider communication, and collaboration. Historically, treatment of vascular anomalies was primarily surgical and medical therapies were limited or ineffective. Recent discoveries of pharmacologic agents effective in treating vascular anomalies have broadened our medical therapeutic options, limiting the need for unnecessary or high-risk procedures and improving patients' quality of life.

Developmental pharmacokinetics of sirolimus: Implications for precision dosing in neonates and infants with complicated vascular anomalies

BACKGROUND

Sirolimus has recently been shown to be efficacious and tolerable in pediatric patients with complicated vascular anomalies. Nevertheless, dosing information remains very limited especially for neonates and infants. The purpose of this study was to develop an age-appropriate sirolimus starting dosing regimen based on the developmental changes in drug elimination capacity using data collected in neonates and infants.

PROCEDURE

A recently developed sirolimus maturation model [Emoto et al. CPT Pharmacometrics Syst Pharmacol, 2016] was used to simulate clearance estimates using realistic age and weight covariates for age cohorts aged 0-24 months. Next, predose concentrations at steady state were generated for each age cohort of neonates and infants. Dose requirements to attain predefined target trough concentration ranges (10-15 and 5-10 ng/ml) were simulated across the different age groups. Starting doses were chosen to maximize the likelihood of achieving sirolimus-targeted concentrations.

RESULTS

The trajectory of simulated sirolimus clearances increased with age and was in agreement with the previous findings in the Phase 2 study. The proposed dosing regimens covered eight age cohorts and resulted in target attainment of more than 75-95% across selected regimens.

CONCLUSIONS

This study identified age-appropriate sirolimus dosing regimens for neonates and infants. The algorithm in combination with therapeutic drug management will facilitate sirolimus precision dosing in young children with vascular anomalies. A prospective evaluation is being planned.

Percutaneous Treatment of Lymphatic Malformations

Lymphatic malformations are slow-flow vascular anomalies composed of dilated lymphatic channels and cysts of varying sizes. Percutaneous treatments, particularly sclerotherapy, play an important role in the treatment of these lesions, often obviating the need for surgical intervention. Owing to the complex nature of these lesions, a multidisciplinary approach should be used to guide diagnosis and management. This submission focuses on the workup and treatment of pediatric lymphatic malformations at our institution, with a focus on sclerotherapy. Therapeutic outcomes and the management of postprocedural complications are also discussed.

[What's new in pediatric dermatology?]

The years 2014-2015 have been rich in paediatric dermatology news in varied areas. Randomized controlled trials including children have been performed, especially in the fields of vascular anomalies, infectiology and immuno-allergology; new classifications and guidelines have been established; scientific research has made new discoveries, including the molecular basis of pediatric nevi and melanoma; epidemiologic works on risk factors have highlighted the need for dermatologists to be aware of prevention (sun prevention but also obesity); and finally, the many publications have taken into account psychological issues in children, such as quality of life, pain, observance or acceptance.

Initial Experience With Propranolol Treatment of Lymphatic Anomalies: A Case Series

Lymphatic malformations (LMs) are congenital lymphatic lesions that impose significant and costly morbidities on affected patients. Treatment options are limited due to incomplete understanding of LM pathobiology. Expression of an activated β2-adrenergic receptor has been described in LM tissue, suggesting that this pathway may contribute to the clinical manifestations of LM. We hypothesized that propranolol, a β-adrenergic receptor antagonist, might improve symptoms of patients with LMs and lymphatic anomalies. A retrospective chart review of patients treated with propranolol as an adjunct therapy was conducted; analyses included demographic characteristics, clinical features, and response to propranolol. Three patients with cystic and noncystic LMs displayed clinical improvement at a minimum dose of 0.7 mg/kg/d, whereas symptomatic relapses were observed when propranolol doses dropped below this threshold. Two patients with Klippel-Trenaunay syndrome demonstrated partial clinical responses with reduced edema. The fetus of a mother treated with propranolol from a gestational age of 35 weeks through delivery displayed arrested growth of a cervicofacial LM. Our retrospective review suggests that propranolol improved symptoms in a subset of patients with lymphatic anomalies. Propranolol treatment may also limit the growth of congenital LMs in utero.

Efficacy and Safety of Sirolimus in the Treatment of Complicated Vascular Anomalies

BACKGROUND AND OBJECTIVES

Complicated vascular anomalies have limited therapeutic options and cause significant morbidity and mortality. This Phase II trial enrolled patients with complicated vascular anomalies to determine the efficacy and safety of treatment with sirolimus for 12 courses; each course was defined as 28 days.

METHODS

Treatment consisted of a continuous dosing schedule of oral sirolimus starting at 0.8 mg/m(2) per dose twice daily, with pharmacokinetic-guided target serum trough levels of 10 to 15 ng/mL. The primary outcomes were responsiveness to sirolimus by the end of course 6 (evaluated according to functional impairment score, quality of life, and radiologic assessment) and the incidence of toxicities and/or infection-related deaths.

RESULTS

Sixty-one patients were enrolled; 57 patients were evaluable for efficacy at the end of course 6, and 53 were evaluable at the end of course 12. No patient had a complete response at the end of course 6 or 12 as anticipated. At the end of course 6, a total of 47 patients had a partial response, 3 patients had stable disease, and 7 patients had progressive disease. Two patients were taken off of study medicine secondary to persistent adverse effects. Grade 3 and higher toxicities attributable to sirolimus included blood/bone marrow toxicity in 27% of patients, gastrointestinal toxicity in 3%, and metabolic/laboratory toxicity in 3%. No toxicity-related deaths occurred.

CONCLUSIONS

Sirolimus was efficacious and well tolerated in these study patients with complicated vascular anomalies. Clinical activity was reported in the majority of the disorders.