NRASQ61R mutation drives elevated angiopoietin-2 expression in human endothelial cells and a genetic mouse model

BACKGROUND

Angiopoietin-2 (Ang-2) is increased in the blood of patients with kaposiform lymphangiomatosis (KLA) and kaposiform hemangioendothelioma (KHE). While the genetic causes of KHE are not clear, a somatic activating NRASQ61R mutation has been found in the lesions of KLA patients.

PROCEDURE

Our study tested the hypothesis that the NRASQ61R mutation drives elevated Ang-2 expression in endothelial cells. Ang-2 was measured in human endothelial progenitor cells (EPC) expressing NRASQ61R and a genetic mouse model with endothelial targeted NRASQ61R. To determine the signaling pathways driving Ang-2, NRASQ61R EPC were treated with signaling pathway inhibitors.

RESULTS

Ang-2 levels were increased in EPC expressing NRASQ61R compared to NRASWT by Western blot analysis of cell lysates and ELISA of the cell culture media. Ang-2 levels were elevated in the blood of NRASQ61R mutant mice. NRASQ61R mutant mice also had reduced platelet counts and splenomegaly with hypervascular lesions, like some KLA patients. mTOR inhibitor rapamycin attenuated Ang-2 expression by NRASQ61R EPC. However, MEK1/2 inhibitor trametinib was more effective blocking increases in Ang-2.

CONCLUSIONS

Our studies show that the NRASQ61R mutation in endothelial cells induces Ang-2 expression in vitro and in vivo. In cultured human endothelial cells, NRASQ61R drives elevated Ang-2 through MAP kinase and mTOR-dependent signaling pathways.

Treatment practices and response in kaposiform hemangioendothelioma: A multicenter cohort study

BACKGROUND AND OBJECTIVES

Kaposiform hemangioendothelioma (KHE) and tufted angioma (TA) are rare vascular tumors in children historically associated with significant morbidity and mortality. This study was conducted to determine first-line therapy in the absence of available prospective clinical trials.

METHODS

Patients from 17 institutions diagnosed with KHE/TA between 2005 and 2020 with more than 6 months of follow-up were included. Response rates to sirolimus and vincristine were compared at 3 and 6 months. Durability of response and response to other treatment modalities were also evaluated.

RESULTS

Of 159 unique KHE/TA subjects, Kasabach-Merritt phenomenon (KMP) was present in 64 (40.3%), and only two patients were deceased (1.3%). Over 60% (n = 96) demonstrated treatment response at 3 months, and more than 70% (n = 114) by 6 months (no significant difference across groups). The vincristine group had higher radiologic response at 3 months compared to sirolimus (72.7% vs. 20%, p = .03), but there were no differences between these groups at 6 months. There were no differences in rates of recurrent or progressive disease between vincristine and sirolimus.

CONCLUSIONS

In this large, multicenter cohort of 159 patients with KHE/TA, rates of KMP were consistent with historical literature, but the mortality rate (1.3%) was much lower. Overall treatment response rates were high (>70%), and there was no significant difference in treatment response or durability of disease comparing sirolimus to vincristine. Our results support individualized treatment decision plans depending on clinical scenario and patient/physician preferences. Response criteria and response rates reported here will be useful for guiding future treatment protocols for vascular tumors.

Microcystic lymphatic malformations in Turner syndrome are due to somatic mosaicism of PIK3CA

Turner syndrome (45,X) is caused by a complete or partial absence of a single X chromosome. Vascular malformations occur due to abnormal development of blood and/or lymphatic vessels. They arise from either somatic or germline pathogenic variants in the genes regulating growth and apoptosis of vascular channels. Aortic abnormalities are a common, known vascular anomaly of Turner syndrome. However, previous studies have described other vascular malformations as a rare feature of Turner syndrome and suggested that vascular abnormalities in individuals with Turner syndrome may be more generalized. In this study, we describe two individuals with co-occurrence of Turner syndrome and vascular malformations with a lymphatic component. In these individuals, genetic testing of the lesional tissue revealed a somatic pathogenic variant in PIK3CA-a known and common cause of lymphatic malformations. Based on this finding, we conclude that the vascular malformations presented here and likely those previously in the literature are not a rare part of the clinical spectrum of Turner syndrome, but rather a separate clinical entity that may or may not co-occur in individuals with Turner syndrome.

Alpelisib for treatment of patients with PIK3CA-related overgrowth spectrum (PROS)

PURPOSE

PIK3CA-related overgrowth spectrum (PROS) encompasses several rare conditions resulting from activating variants in PIK3CA. Alpelisib, a PI3Kα-selective inhibitor, targets the underlying etiology of PROS, offering a novel therapeutic approach to current management strategies. This study evaluated the safety and efficacy of alpelisib in pediatric and adult patients with PROS.

METHODS

EPIK-P1 (NCT04285723) was a non-interventional, retrospective chart review of 57 patients with PROS (≥2 years) treated with alpelisib through compassionate use. Patients had severe/life-threatening PROS-related conditions and confirmed PIK3CA pathogenic variant. The primary end point assessed patient response to treatment at Week 24 (6 months).

RESULTS

Twenty-four weeks (6 months) after treatment initiation, 12 of 32 (37.5%) patients with complete case records included in the analysis of the primary end point experienced a ≥20% reduction in target lesion(s) volume. Additional clinical benefit independent from lesion volume reduction was observed across the full study population. Adverse events (AEs) and treatment-related AEs were experienced by 82.5% (47/57) and 38.6% (22/57) of patients, respectively; the most common treatment-related AEs were hyperglycemia (12.3%) and aphthous ulcer (10.5%). No deaths occurred.

CONCLUSION

EPIK-P1 provides real-world evidence of alpelisib effectiveness and safety in patients with PROS and confirms PI3Kα as a valid therapeutic target for PROS symptom management.

Universal DNA methylation age across mammalian tissues

Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylation Consortium, which encompass 59 tissue types across 185 mammalian species. These predictive models estimate mammalian tissue age with high accuracy (r > 0.96). Age deviations correlate with human mortality risk, mouse somatotropic axis mutations and caloric restriction. We identified specific cytosines with methylation levels that change with age across numerous species. These sites, highly enriched in polycomb repressive complex 2-binding locations, are near genes implicated in mammalian development, cancer, obesity and longevity. Our findings offer new evidence suggesting that aging is evolutionarily conserved and intertwined with developmental processes across all mammals.

Genomic profiling informs diagnoses and treatment in vascular anomalies

Vascular anomalies are malformations or tumors of the blood or lymphatic vasculature and can be life-threatening. Although molecularly targeted therapies can be life-saving, identification of the molecular etiology is often impeded by lack of accessibility to affected tissue samples, mosaicism or insufficient sequencing depth. In a cohort of 356 participants with vascular anomalies, including 104 with primary complex lymphatic anomalies (pCLAs), DNA from CD31+ cells isolated from lymphatic fluid or cell-free DNA from lymphatic fluid or plasma underwent ultra-deep sequencing thereby uncovering pathogenic somatic variants down to a variant allele fraction of 0.15%. A molecular diagnosis, including previously undescribed genetic causes, was obtained in 41% of participants with pCLAs and 72% of participants with other vascular malformations, leading to a new medical therapy for 63% (43/69) of participants and resulting in improvement in 63% (35/55) of participants on therapy. Taken together, these data support the development of liquid biopsy-based diagnostic techniques to identify previously undescribed genotype-phenotype associations and guide medical therapy in individuals with vascular anomalies.

Pathogenic variants in PIK3CA are associated with clinical phenotypes of kaposiform lymphangiomatosis, generalized lymphatic anomaly, and central conducting lymphatic anomaly

Complex lymphatic anomalies are debilitating conditions characterized by aberrant development of the lymphatic vasculature (lymphangiogenesis). Diagnosis is typically made by history, examination, radiology, and histologic findings. However, there is significant overlap between conditions, making accurate diagnosis difficult. Recently, genetic analysis has been offered as an additional diagnostic modality. Here, we describe four cases of complex lymphatic anomalies, all with PIK3CA variants but with varying clinical phenotypes. Identification of PIK3CA resulted in transition to a targeted inhibitor, alpelisib. These cases highlight the genetic overlap between phenotypically diverse lymphatic anomalies.

Kaposiform lymphangiomatosis: Diagnosis, pathogenesis, and treatment

Kaposiform lymphangiomatosis (KLA) is a life-threatening rare disease that can cause substantial morbidity, mortality, and social burdens for patients and their families. Diagnosis often occurs long after initial symptoms, and there are few centers in the world with the expertise to diagnose and care for patients with the disease. KLA is a lymphatic anomaly and significant advancements have been made in understanding its pathogenesis and etiology since its first description in 2014. This review provides multidisciplinary, comprehensive, and state-of-the-art information on KLA patient presentation, diagnostic imaging, pathology, organ involvement, genetics, and pathogenesis. Finally, we describe current therapeutic approaches, important areas for research, and challenges faced by patients and their families. Further insights into the pathogenesis of KLA may advance our understanding of other vascular anomalies given that similar signaling pathways may be involved.

Multifocal Kaposiform Hemangioendothelioma in a Newborn With Confirmatory Histopathology

Kaposiform hemangioendothelioma is classified as a locally aggressive vascular tumor of childhood resulting from abnormal angiogenesis and lymphangiogenesis. Most commonly, KHE presents as a single tissue mass, ranging from an erythematous papule to a violaceous indurated tumor. Definitive diagnosis requires tissue sampling with the demonstration of ill-defined nodules and fascicles of spindle-shaped D2-40 positive endothelial cells, forming slit-like vascular channels. This newborn presented with multifocal cutaneous Kaposiform hemangioendothelioma associated with Kasabach-Merritt phenomenon confirmed on histopathology with immunostaining.

Alternative Evaluation of the Right Axillary Lymphatic Pathway by Using Dynamic Contrast-enhanced MR Lymphangiography

The lymphatic system plays an integral part in fluid homeostasis. Disturbances in lymphatic pathways are congenital, posttraumatic, or posttreatment related, such as after Fontan palliation. Lymphatic pathway evaluation is challenging because of the difficulty in introducing contrast material into the lymphatics. Intranodal, intramesenteric, and intrahepatic dynamic contrast-enhanced MR lymphangiography (DCMRL) offer better visualization of major lymphatic pathways. However, these techniques exclude pathways outside the central conduction system, preventing the visualization of abnormalities and, thus, administration of treatment. The authors describe alternative imaging of an axillary pathway via DCMRL in a patient with a symptomatic chylous effusion not previously assessed with current techniques. Keywords: Lymphatic, MR-Dynamic Contrast Enhanced, Pediatrics, Thorax, Pleura Supplemental material is available for this article. © RSNA, 2022.

Cerebrospinal fluid leak in epidural venous malformations and blue rubber bleb nevus syndrome

OBJECTIVE

Clinical manifestations of blue rubber bleb nevus syndrome (BRBNS) and multifocal venous malformation (MVM) vary depending on the location of the lesions. The aim of this study was to assess the risk of developing CSF leaks in patients with epidural venous malformations (VMs).

METHODS

The authors retrospectively investigated the relationship between the development of a CSF leak and the presence of epidural VMs.

RESULTS

Nine patients (5 females) had epidural VMs and presentation that was confirmatory or suggestive of a CSF leak: 4 had BRBNS, 4 had MVMs, and 1 had a solitary VM. Of 66 patients with BRBNS, clinical and imaging features of CSF leak were noted in 3 (4.5%) with epidural VMs at the age of 11-44 years. A fourth patient had suggestive symptoms without imaging confirmation. An epidural blood patch was ineffective in 2 patients, both with more than one source of leakage, requiring surgical repair or decompression. Symptomatic downward displacement of the cerebellar tonsils was noted in 3 patients with MVM and 1 with a solitary VM; 3 required surgical decompression.

CONCLUSIONS

These findings suggest an increased risk of CSF leak in patients with epidural VM, including BRBNS, MVMs, and solitary VMs. Awareness of the association between epidural VM and CSF leakage may facilitate earlier diagnosis and therapeutic intervention.

Multicompartment Dynamic Contrast Magnetic Resonance Lymphangiography in Diagnosis of Complicated Lymphatic Anomaly

Background: To describe the dynamic contrast magnetic resonance lymphangiography (DCMRL) findings of three patients with complicated lymphatic anomaly (CLA) and protein losing enteropathy. We further discuss the importance of a multicompartment (intrahepatic [IH], intramesenteric [IM], and intranodal [IN]) DCMRL in delineating central lymphatic flow pathologies. Methods and Results: This is a retrospective study of three patients-one adult and two children who individually underwent the three-compartment DCMRL, namely IN-DCMRL, IH-DCMRL, and IM-DCMCRL. Findings from the results of the DCMRL for these three patients were obtained from the medical records and compared. Using the multicompartment imaging modalities, chylous fluid leakage into the peritoneum was observed using IM-DCMRL and IH-DCMRL but not IN-DCMRL for one of the patients in the case series. In contrast, leakage of chyle into the mediastinum was noted using IN-DCMRL but not IH-DCMRL and IM-DCMRL on another patient in this case series. Conclusion: Owing to the variability in outlining lymphatic flow pathologies, multicompartment imaging gives a more global picture of individual conduction disorders, has the potential to improve clinical assessment, and in some cases leads to a diagnosis of the abnormality and thus provides a better understanding of lymphatic flow anomalies in patients with CLAs.

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.

Kaposiform Lymphangiomatosis: Pathologic Aspects in 43 Patients

Kaposiform lymphangiomatosis is an uncommon generalized lymphatic anomaly with distinctive clinical, radiologic, histopathologic, and molecular findings. Herein, we document the pathology in 43 patients evaluated by the Boston Children's Hospital Vascular Anomalies Center from 1999 to 2020. The most frequent presentations were respiratory difficulty, hemostatic abnormalities, and a soft tissue mass. Imaging commonly revealed involvement of some combination of mediastinal, pulmonary, pleural, and pericardial compartments and most often included spleen and skeleton. Histopathology was characterized by dilated, redundant, and abnormally configured lymphatic channels typically accompanied by dispersed clusters of variably canalized, and often hemosiderotic, spindled lymphatic endothelial cells that were immunopositive for D2-40, PROX1, and CD31. An activating lesional NRAS variant was documented in 9 of 10 patients. The clinical course was typically aggressive, marked by hemorrhage, thrombocytopenia, diminished fibrinogen levels, and a mortality rate of 21%.

Pathogenic variants in MDFIC cause recessive central conducting lymphatic anomaly with lymphedema

Central conducting lymphatic anomaly (CCLA), characterized by the dysfunction of core collecting lymphatic vessels including the thoracic duct and cisterna chyli, and presenting as chylothorax, pleural effusions, chylous ascites, and lymphedema, is a severe disorder often resulting in fetal or perinatal demise. Although pathogenic variants in RAS/mitogen activated protein kinase (MAPK) signaling pathway components have been documented in some patients with CCLA, the genetic etiology of the disorder remains uncharacterized in most cases. Here, we identified biallelic pathogenic variants in MDFIC, encoding the MyoD family inhibitor domain containing protein, in seven individuals with CCLA from six independent families. Clinical manifestations of affected fetuses and children included nonimmune hydrops fetalis (NIHF), pleural and pericardial effusions, and lymphedema. Generation of a mouse model of human MDFIC truncation variants revealed that homozygous mutant mice died perinatally exhibiting chylothorax. The lymphatic vasculature of homozygous Mdfic mutant mice was profoundly mispatterned and exhibited major defects in lymphatic vessel valve development. Mechanistically, we determined that MDFIC controls collective cell migration, an important early event during the formation of lymphatic vessel valves, by regulating integrin β₁ activation and the interaction between lymphatic endothelial cells and their surrounding extracellular matrix. Our work identifies MDFIC variants underlying human lymphatic disease and reveals a crucial, previously unrecognized role for MDFIC in the lymphatic vasculature. Ultimately, understanding the genetic and mechanistic basis of CCLA will facilitate the development and implementation of new therapeutic approaches to effectively treat this complex disease.

Parkes Weber syndrome with lymphedema caused by a somatic KRAS variant

Parkes Weber syndrome is a vascular malformation overgrowth condition typically involving the legs. Its main features are diffuse arteriovenous fistulas and enlargement of the limb. The condition has been associated with pathogenic germline variants in RASA1 and EPHB4. We report two individuals with Parkes Weber syndrome of the leg and primary lymphedema containing a somatic KRAS variant (NM_004985.5:c.35G > A; p.Gly12Asp). KRAS variants, which cause somatic intracranial and extracranial arteriovenous malformations, also result in Parkes Weber syndrome with lymphatic malformations.

Respiratory Failure in Noonan Syndrome Treated by Microsurgical Thoracic Duct-Venous Anastomosis

Noonan Syndrome is a disorder characterized by central and peripheral lymphatic conducting anomalies, leading to chylothorax, chylous ascites, and metabolic derangement. Novel imaging modalities including dynamic contrast magnetic resonance lymphangiography (DCMRL) and intranodal lymphangiography have allowed for increased visualization of lymphatic pathology. We describe the first study of a 61-year-old male with Noonan syndrome who developed severe pulmonary insufficiency and chylothoraces. DCMRL and intranodal lymphangiography demonstrated central thoracic duct (TD) occlusion. The patient's condition significantly improved following microsurgical TD-venous anastomosis assisted by TD catherization for imaging guidance, resulting in decompression of the lymphatic system and resolution of the pulmonary symptoms.

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.

EPIK-P2: A prospective phase 2, double-blind, randomized, placebo-controlled study of alpelisib in pediatric and adult patients (Pts) with PIK3CA-related overgrowth spectrum (PROS)

TPS3160

Background: Somatic gain-of-function mutations in the PIK3CA gene, encoding the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) catalytic α subunit (p110α), can result in PI3K pathway hyperactivation. PROS is an umbrella term for rare, phenotypically varied, but overlapping features driven by PIK3CA mutations. Disease onset is often congenital or in early childhood; presentation ranges widely from localized overgrowth to pleiotropic, severe overgrowth. Complications depend on anatomical site and extent of overgrowth. Management of PROS currently involves symptomatic treatment of its manifestations; an unmet need exists for targeted, systemic therapies. Alpelisib, a PI3Kα inhibitor, has demonstrated encouraging clinical observations and a promising safety profile; after 6 mo of treatment, pediatric and adult pts with PROS experienced improvements in symptoms without requiring surgery. A low rate of side effects was observed (Venot Q, et al. Nature. 2018;558:540-6). Methods: EPIK-P2 is a prospective, phase 2, multicenter study with an upfront 16-week, randomized, double-blind, placebo-controlled period. Key eligibility criteria include male or female ≥6 yr of age with PROS and symptomatic and/or progressive overgrowth; ≥1 PROS-related measurable lesion confirmed by a Blinded Independent Review Committee (BIRC) and documented somatic PIK3CA mutation. Pts with isolated cases of macrodactyly, epidermal nevus/nevi, or macrocephaly in absence of other PROS-related lesions; previous treatment with PI3K inhibitor(s); or debulking surgery within 3 mo are not eligible. Approximately 138 pts will be enrolled into 2 groups comprising adult (age ≥18 yr) and pediatric (ages 6-17 yr) pts. Pts will be randomized 2:1 to daily oral alpelisib or matching placebo; adults will receive 125 mg and pediatric pts 50 mg. After 16 weeks, pts randomized to placebo will switch to alpelisib in a blinded fashion; pts receiving alpelisib will continue alpelisib. Treatment will continue for up to 5 yr. The primary objective is to demonstrate the efficacy of alpelisib by the proportion of pts randomized to alpelisib with a response at Week 24 in each group. Response is defined as ≥20% volume reduction in the symptomatic target lesion(s) per BIRC. The key secondary objective is to demonstrate efficacy of alpelisib vs placebo based on the proportion of pts in each group with response at Week 16. Other secondary outcomes include safety and tolerability, duration of response, overall clinical response rates, changes in symptoms and comorbidities, patient-reported outcomes, pharmacokinetics, and healthcare utilization. An exploratory group of pts (n = 12) ages 2-5 yr will be later enrolled once a starting dose of alpelisib is confirmed in these pts. Enrollment of 150 pts is anticipated. Clinical trial information: NCT04589650.

The Clinical Spectrum of PTEN Hamartoma Tumor Syndrome: Exploring the Value of Thyroid Surveillance

INTRODUCTION

Phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) comprises a collection of clinical features characterized by constitutional variants in PTEN. Several guidelines recommend thyroid screening, beginning at the pediatric age at the time of PHTS diagnosis; however, the benefits of early surveillance has not been well defined.

METHODS

We conducted a retrospective investigation of patients followed up at the Children's Hospital of Philadelphia with a diagnosis of PHTS between January 2003 and June 2019. In total, 81 patients younger than 19 years were identified.

RESULTS

The most common clinical feature at presentation was macrocephaly (85.1%), followed by impaired development (42.0%), skin/oral lesions (30.9%), and autism spectrum disorder (27.2%). A total of 58 of 81 patients underwent thyroid surveillance, with 30 patients (51.7%) found to have a nodule(s). Ultimately, 16 patients underwent thyroidectomy, with 7.4% (6/81) diagnosed with thyroid cancer. All thyroid cancer patients were older than 10 years at diagnosis, and all displayed low-invasive behavior. Of the patients younger than 10 years at the time of thyroid ultrasound (US) surveillance, 71.4% (15/21) had a normal US. The remaining 6 patients had thyroid nodules, including 4 undergoing thyroid surgery with benign histology.

DISCUSSION/CONCLUSION

Patients with macrocephaly, impaired cognitive development and thyroid nodules, and/or early-onset gastrointestinal polyps should undergo constitutional testing for PHTS. There does not appear to be a clinical advantage to initiating thyroid US surveillance before 10 years of age. In PHTS patients with a normal physical examination, thyroid US surveillance can be delayed until 10 years of age.

Diffuse Venous Malformations of the Upper Extremity (Bockenheimer Disease): Diagnosis and Management

BACKGROUND

Diffuse venous malformations that involve all tissues in the upper limb and ipsilateral chest wall are known as "phlebectasia of Bockenheimer." The authors describe their experience with management of this uncommon vascular anomaly.

METHODS

The authors' Vascular Anomalies Center registry comprised 18,766 patients over a 40-year period. This review identified 2036 patients with venous malformations of the extremities (10.8 percent), of whom only 80 (0.43 percent) had Bockenheimer disease. The authors retrospectively analyzed patient characteristics, diagnostics, treatments, and complications.

RESULTS

The venous malformation was first noted at birth or within the first few years of life with slow and gradual progression. Pain was related to engorgement of the limb. Thromboses and phleboliths were common, but diffuse intravascular coagulopathy occurred in only 12 patients (15 percent). Skeletal involvement was demonstrated as lytic lesions, cortical scalloping, osteopenia, and pathologic fractures. Management included compression garments (100 percent), sclerotherapy (27.5 percent), and resection of symptomatic areas in 35 percent of patients. Adjunctive pharmacologic medication was given in 7.5 percent. Following resection, 17 patients (60 percent) had one or more complications: hematoma, wound dehiscence, flap loss, contracture, and psychosis. There were no deaths. Symptoms improved in all patients with useful functional outcomes.

CONCLUSIONS

The decision to pursue compression, sclerotherapy, pharmacologic treatment, or resection alone or in combination was made by an interdisciplinary team. Although extensive venous malformations cannot be completely ablated, debulking of symptomatic regions, resection of neuromas, and noninvasive treatments improve the quality of life. Despite the bulk and weight of the arm, forearm, and hand, and the ominous appearance on magnetic resonance imaging, these patients remain functional.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Kaposiform lymphangiomatosis effectively treated with MEK inhibition

Kaposiform lymphangiomatosis (KLA) is a rare lymphatic anomaly primarily affecting the mediastinum with high mortality rate. We present a patient with KLA and significant disease burden harboring a somatic point mutation in the Casitas B lineage lymphoma (CBL) gene. She was treated with MEK inhibition with complete resolution of symptoms, near-complete resolution of lymphatic fluid burden, and remodeling of her lymphatic system. While patients with KLA have been reported to harbor mutations in NRAS, here we report for the first time a causative mutation in the CBL gene in a patient with KLA, successfully treated with Ras pathway inhibition.

Overgrowth syndromes and new therapies

Overgrowth syndromes represent a diverse group of disorders with overlapping features. Interdisciplinary management by a team of experts in vascular anomalies is crucial for establishing the correct diagnosis and optimizing outcomes for these patients. Unique management considerations include increased risk for thrombosis and in some cases, cancer. In recent years, research has demonstrated that these disorders are primarily caused by somatic mutations in growth pathways, particularly the PI3K-mTOR pathway. This improved understanding had led to promising new therapies for this group of patients.

Kaposiform lymphangiomatosis treated with multimodal therapy improves coagulopathy and reduces blood angiopoietin-2 levels

Kaposiform lymphangiomatosis (KLA) is a rare, life-threatening congenital lymphatic malformation. Diagnosis is often delayed due to complex indistinct symptoms. Blood angiopoietin-2 (ANG2) levels are elevated in KLA and may be useful as a biomarker to monitor disease status. We report a 7-year-old male child with easy bruising, inguinal swelling, and consumptive coagulopathy, diagnosed with KLA. A multimodal treatment regimen of prednisone, sirolimus, vincristine, and adjunctive zoledronate was used. Plasma ANG2 levels were highly elevated at diagnosis but decreased during treatment. The patient showed significant clinical improvement over a 38-month period and normalization of ANG2 levels correlated with resolution of the coagulopathy.

Management of infantile hemangiomas during the COVID pandemic

The COVID-19 pandemic has caused significant shifts in patient care including a steep decline in ambulatory visits and a marked increase in the use of telemedicine. Infantile hemangiomas (IH) can require urgent evaluation and risk stratification to determine which infants need treatment and which can be managed with continued observation. For those requiring treatment, prompt initiation decreases morbidity and improves long-term outcomes. The Hemangioma Investigator Group has created consensus recommendations for management of IH via telemedicine. FDA/EMA-approved monitoring guidelines, clinical practice guidelines, and relevant, up-to-date publications regarding initiation and monitoring of beta-blocker therapy were used to inform the recommendations. Clinical decision-making guidelines about when telehealth is an appropriate alternative to in-office visits, including medication initiation, dosage changes, and ongoing evaluation, are included. The importance of communication with caregivers in the context of telemedicine is discussed, and online resources for both hemangioma education and propranolol therapy are provided.

Constitutively active PIK3CA mutations are expressed by lymphatic and vascular endothelial cells in capillary lymphatic venous malformation

Capillary lymphatic venous malformations (CLVM) are complex vascular anomalies characterized by aberrant and enlarged lymphatic and blood vessels. CLVM appear during fetal development and enlarge after birth, causing life-long complications such as coagulopathy, pulmonary embolism, chronic pain, and disfigurement. Treatment includes surgical debulking, amputation, and recurrent sclerotherapy. Somatic, mosaic mutations in the 110-kD catalytic α-subunit of phosphoinositide-3-kinase (PIK3CA) gene have been previously identified in affected tissues from CLVM patients; however, the cell population harboring the mutation is still unknown. In this study, we hypothesized that endothelial cells (EC) carry the PIK3CA mutations and play a major role in the cellular origin of CLVM. We isolated EC from the lesions of seven patients with CLVM and identified PIK3CA hotspot mutations. The CLVM EC exhibited constitutive phosphorylation of the PI3K effector AKT as well as hyperproliferation and increased resistance to cell death compared to normal EC. Inhibitors of PIK3CA (BYL719) and AKT (ARQ092) attenuated the proliferation of CLVM EC in a dose-dependent manner. A xenograft model of CLVM was developed by injecting patient-derived EC into the flanks of immunocompromised mice. CLVM EC formed lesions with enlarged lymphatic and vascular channels, recapitulating the patient histology. EC subpopulations were further obtained by both immunomagnetic separation into lymphatic EC (LEC) and vascular EC (VEC) and generation of clonal populations. By sequencing these subpopulations, we determined that both LEC and VEC from the same patient express the PIK3CA mutation, exhibit increased AKT activation and can form lymphatic or vascular lesions in mouse.

Sirolimus for the treatment of juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibroma (JNA) is a pathologically benign yet locally aggressive and destructive tumor that develops in the choana and nasopharynx. Historical treatment of JNA has included embolization, surgical resection, and radiation. Here, we describe three patients who received therapy with the mTOR inhibitor sirolimus with improvement in clinical symptoms, imaging, and overall well-being.

Clinical characterization and long-term outcomes in pediatric epithelioid hemangioendothelioma

There is a paucity of information about the clinical characteristics and long-term outcomes of pediatric epithelioid hemangioendothelioma (EHE), a rare vascular neoplasm commonly presenting in adulthood. In our case series of 24 patients with EHE aged 2-26 years, the majority presented with multi-organ disease. Progression was seen in 63% of patients with a mean time to progression of 18.4 months (range: 0-72). Three patients treated with sirolimus achieved stable disease or partial response for >2.5 years. Longitudinal prospective pediatric studies are needed to develop standardized approaches to surgical and medical management.

A Primer on a Comprehensive Genetic Approach to Vascular Anomalies

The field of vascular anomalies has grown tremendously in the last few decades with the identification of key molecular pathways and genetic mutations that drive the formation and progression of vascular anomalies. Understanding these pathways is critical for the classification of vascular anomalies, patient care, and development of novel therapeutics. The goal of this review is to provide a basic understanding of the classification of vascular anomalies and knowledge of their underlying molecular pathways. Here we provide an organizational framework for phenotype/genotype correlation and subsequent development of a diagnostic and treatment roadmap. With the increasing importance of genetics in the diagnosis and treatment of vascular anomalies, we highlight the importance of clinical geneticists as part of a comprehensive multidisciplinary vascular anomalies team.

Multidisciplinary guidelines for initial evaluation of complicated lymphatic anomalies-expert opinion consensus

OBJECTIVE

Complicated lymphatic anomalies (CLAs) are chronic, progressive, and debilitating conditions that share clinical features, yet key elements for optimal evaluation and management have not been established. We aimed to formulate expert opinion consensus-based guidelines for comprehensive evaluation of CLAs.

STUDY DESIGN

Patient support groups dedicated to CLAs organized an international conference for vascular anomaly experts from 16 specialties to address the objective. Participants received a set of questions before the meeting and reviewed the literature. Data extracted from international lymphatic anomaly registries were presented and the group separated for panel discussions during the conference. The recommendations achieving consensus within the panel were presented to the entire audience. Open debate occurred until majority approval was achieved.

RESULTS

The expert group was composed of 52 physicians who defined the clinical elements required to evaluate and diagnose a CLA. The radiology panel established the preferred anatomical and functional imaging methods for diagnosis and the elements required to be described during interpretation. Two medical panels compiled the metabolic and hematologic tests at diagnosis and also recommended functional studies. The surgical group recommended precautions for biopsy and the pathology panel provided biopsy specimen processing guidelines.

CONCLUSIONS

Patients with CLAs require a comprehensive and targeted diagnostic plan for appropriate management, prevention of complications, and conservation of resources. As this population is managed by diverse medical and surgical specialties, we offer an expert multidisciplinary consensus-based opinion on the current literature and on data extracted from international lymphatic anomaly registries.

Practical Genetic and Biologic Therapeutic Considerations in Vascular Anomalies

Vascular anomalies are classified as either tumors or malformations based on clinical findings rendered through radiologic evaluation, physical exam, and histologic interpretation. These findings comprise the phenotype of the disorder. Recently, advances in the molecular genetics of vascular anomalies have shed light on the genotype of these disorders. These phenotype/genotype characterizations will provide a more precise classification of vascular anomalies and identify potential therapeutic targets for expanded treatment options in the future. In this chapter, we will review the phenotype/genotype characterizations and the possible therapeutic pathways for targeted pharmacologic therapy.

Signaling pathways and inhibitors of cells from patients with kaposiform lymphangiomatosis

BACKGROUND

Kaposiform lymphangiomatosis (KLA) is a rare lymphatic anomaly with significant morbidity and mortality. KLA is characterized by diffuse multifocal lesions comprised of focal areas of "kaposiform" spindled cells accompanying malformed lymphatic channels. The goal of this study was to identify activated signaling pathways in cells isolated from three KLA patients for the purpose of testing new therapies.

PROCEDURE

Cells were obtained from the lungs of one patient isolated at autopsy and the spleen of two patients removed in surgery due to disease complications. A protein kinase array was performed on the KLA cell lysates and normal lymphatic endothelial cells.

RESULTS

Higher activation of key signaling pathways in the KLA cells, including PRAS40, AKT1/2/3, and ERK-1/2, was identified by protein kinase array and confirmed by Western blot analysis. This indicated a role for highly activated PI3K-AKT and MAPK-ERK-1/2 signaling pathways in KLA cells. Cell proliferation studies assessed PI3K inhibitors (LY294002; BYL719), AKT inhibitor ARQ092, mTOR inhibitor rapamycin, and MAPK inhibitor U0126. These studies demonstrated that PI3K-AKT-mTOR and MAPK signaling are important mediators of KLA cell proliferation. BYL719 and rapamycin were more effective at inhibiting KLA cell proliferation than U0126.

CONCLUSIONS

Our studies using cells from KLA patient lesions demonstrate that these cells are highly proliferative and the PI3K-AKT-mTOR and MAPK pathways are promising therapeutic targets. Development and clinical trials of PI3K, AKT, and MAPK inhibitors for cancer treatment and the data in this study lend support for early clinical trials assessing the efficacy of these inhibitors in KLA patients.

Imaging findings in epithelioid hemangioendothelioma

PURPOSE-OBJECTIVE

Epithelioid hemangioendothelioma (EHE) is a rare vascular malignancy with varying biologic behavior. The purpose of this study was to identify imaging findings most characteristic of EHE.

METHODS

Retrospective review of clinical and imaging records in patients referred to our Vascular Anomalies Center over a 17 year period with biopsy proven EHE.

RESULTS

We evaluated 29 patients (17 F) with median age of 16 years (range 2-76 y). The most common presenting symptoms were pain (n = 13) and palpable mass (n = 7). 22 (70%) had multifocal disease. Most common sites of involvement were lung (n = 25), liver (n = 16), bone (n = 12), soft tissue (n = 3) and lymph nodes (n = 1). Of patients with single site disease, 3 had lung, 3 liver, and 1 had bone lesions. In 18/25 with lung disease, there were multiple nodules of varying sizes and characteristics. In 14/16 with hepatic disease there were multiple nodules with predominantly peripheral distribution. Subcapsular retraction was seen in 10/16 and a "lollipop" sign (hepatic or portal vein tapering at the edge of a well-defined hypoenhancing lesion) identified in 5/16. Of 12 osseous lesions, 11 were lytic, 8 involved vertebrae and 9 involved the axial skeleton.

CONCLUSION

EHE has varied imaging findings. The most common sites are lungs, liver, and bone, with multi-organ involvement seen in most. Lung disease is most commonly characterized by multiple nodules. Hepatic lesions demonstrate the most distinctive findings, with peripheral distribution, lack of early enhancement, subcapsular retraction and "lollipop" sign. Osseous lesions are commonly lytic and more prevalent in the axial skeleton.

Cancer Risk in Klippel-Trenaunay Syndrome

Background: Klippel-Trenaunay syndrome (KTS) is an overgrowth syndrome defined by capillary/venous/lymphatic malformations (CVLM) with soft tissue and/or bone hypertrophy. Whether KTS predisposes to cancer is not clear. Methods and Results: We surveyed members of the K-T Support Group (KTSG) and reviewed PubMed for "Klippel Trenaunay Syndrome" or "CVLM" and "cancer." Individuals with cancer were reviewed for confirmation of KTS, tumor type, location, and age at presentation. Of 223 KTSG respondents, 24 (10.8%) reported 26 malignancies or benign brain tumors (diagnosed from 6 months to 68 years of age, median 41 years), including 3 who were younger than 18 years (2 with Wilms tumor). Nine of twenty-six cancers were basal cell carcinomas (4% of respondents). From 475 articles, we identified 11 cancers or brain tumors in 10 individuals with KTS. Four of these were in children (Wilms tumor n = 2; rhabdomyosarcoma n = 1; serous borderline tumor n = 1). Tumors in adults included basal cell carcinoma (n = 1), squamous cell carcinoma of skin (n = 2), and angiosarcoma, Hodgkin disease, glioblastoma, malignant hemangiopericytoma in one patient each. Ulceration or lymphedema associated with VLM or capillary malformations were associated with some basal cell or squamous cell carcinomas and angiosarcomas. Conclusions: The risk of embryonal cancer other than Wilms tumor in children with KTS does not appear to be higher than in the general population. Wilms tumor incidence is under 5%, and routine surveillance is not indicated. In adults, particular attention should be paid to skin in the area of malformations. These conclusions may not apply to all overgrowth syndromes with vascular malformations.

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.

Characterization of long-term outcomes for pediatric patients with epithelioid hemangioma

Epithelioid hemangioma (EH) is a rare benign vascular tumor that occurs in soft tissues and bone and presents between the third and sixth decades of life. Little is known about the clinical course and outcomes of pediatric EH. We report 11 patients diagnosed with EH at a median age of 14.4 years. One patient treated with interferon and one with sirolimus exhibited partial response for >2 years. Although a benign neoplasm, EH is difficult to manage without standard protocols and portends considerable morbidity. Our findings suggest medical management, particularly sirolimus, may benefit these patients; however, long-term follow-up is needed.

Guidance Document for Hepatic Hemangioma (Infantile and Congenital) Evaluation and Monitoring

OBJECTIVE

To define the types of hepatic hemangiomas using the updated International Society for the Study of Vascular Anomalies classification and to create a set of guidelines for their diagnostic evaluation and monitoring.

STUDY DESIGN

We used a rigorous, transparent consensus protocol defined by an approved methodology, with input from multiple pediatric experts in vascular anomalies from hematology-oncology, surgery, pathology, radiology, and gastroenterology.

RESULTS

In the first section, we define the subtypes of hepatic hemangiomas based on the clinical course, histology, and radiologic characteristics. We recommend against using the term "hemangioma" for any vascular malformations affecting the liver or any hypervascular tumors that are not characterized by the approved definitions. We recommend against using the term "hemangioendothelioma" for infantile or congenital hemangioma. The following 2 sections dedicated to infantile hepatic hemangioma and to congenital hepatic hemangioma individually describe these subtypes in further detail, including complications to be considered during monitoring and respectively recommended screening evaluations.

CONCLUSIONS

Although institutional variations may exist for specific clinical details, a clear understanding of the diagnosis of hepatic hemangiomas affecting children and the possible complications that require screening during the monitoring period should be standard. As children with hepatic hemangiomas are managed by different medical and surgical specialties, we offer an expert opinion multidisciplinary consensus based on current literature and on data extracted from the liver hemangioma registry.

Pulmonary thromboembolic events in patients with congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and spinal/skeletal abnormalities and Klippel-Trénaunay syndrome

OBJECTIVE

Patients with Klippel-Trénaunay syndrome (KTS) and congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and spinal/skeletal abnormalities (CLOVES) syndrome have central phlebectasia and enlarged persistent embryonic veins that are often incompetent and prone to thromboembolism. The purpose of the study was to determine the presence of phlebectasia and the incidence of symptomatic pulmonary embolism (PE).

METHODS

A retrospective review was conducted of patients referred to the Vascular Anomalies Center at our institution during a 21-year period who were diagnosed with KTS and CLOVES syndrome. Of these, the patients who had PE were screened for thromboembolic risk factors in addition to phlebectasia and the presence of persistent embryonic veins. Treatment outcomes following subsequent endovascular and medical therapies were reported.

RESULTS

A total of 12 KTS patients of 96 (12.5%) and 10 CLOVES syndrome patients of 110 (9%) suffered PE. Fourteen patients (64%) developed PE after surgery or sclerotherapy. All of the patients had abnormally dilated central or persistent embryonic veins; 20 patients were treated with anticoagulation (1 died at the time of presentation, and no information was available for 1) after PE, and 14 (66%) patients underwent subsequent endovascular treatment. Five patients developed recurrent PE despite anticoagulation. Two of the patients died of PE. No patients treated with endovascular closure of dilated veins had subsequent evidence of PE.

CONCLUSIONS

Patients with KTS and CLOVES syndrome are at high risk for PE, particularly in the postoperative period.

Combined mTOR and MEK inhibition is an effective therapy in a novel mouse model for angiosarcoma

Angiosarcoma is an aggressive malignancy of vascular origin that occurs de novo or in the context of previous cancer therapy. Despite multi-modal aggressive treatment including surgical resection, chemotherapy, and radiation, five-year overall survival remains poor at 35%. Due to its rarity, little is known about its molecular pathology and clinical trials have been extremely difficult to conduct. Development of animal models for rare diseases like angiosarcoma is critical to improve our understanding of tumorigenesis and to test novel treatment regimens. A genetically engineered mouse model for angiosarcoma was generated by conditional deletion of Trp53, Pten, and Ptpn12 in endothelial cells. Tumors arising from these mice recapitulate the histology and molecular pathology of the human disease including hyperactivation of the PI3K/mTOR and MAPK signaling pathways. Treatment of tumor-bearing mice with mTOR or MEK inhibitors effectively inactivated signaling and resulted in reduced proliferation and elevated apoptosis leading to tumor regression. The effect of treatment on tumor growth was transient and proliferation was restored after a period of dormancy. However, combined inhibition of mTOR and MEK resulted in profound tumor regression which was sustained for the duration of treatment. These results suggest that angiosarcoma may be effectively treated by this drug combination. 

Urine cell-free DNA is a biomarker for nephroblastomatosis or Wilms tumor in PIK3CA-related overgrowth spectrum (PROS)

Purpose

We set out to facilitate the molecular diagnosis of patients with PIK3CA-related overgrowth spectrum (PROS), a heterogeneous somatic disorder characterized by variable presentations of segmental overgrowth, vascular malformations, skin lesions, and nephroblastomatosis, rare precursor lesions to Wilms tumor (WT). Molecular diagnosis of PROS is challenging due to its mosaic nature, often requiring invasive biopsies.

Methods

Digital droplet polymerase chain reaction was used to analyze tissues including urine, saliva, buccal cells, and blood, from eight patients with PROS. Further analyses were performed on plasma and urine cell-free DNA (cfDNA).

Results

PIK3CA variants were detected in plasma cfDNA at levels up to 0.5% in 50% of tested samples. In addition, high levels of PIK3CA variants in urine cfDNA correlated with a history of nephroblastomatosis compared to patients without renal involvement (p<0.05).

Conclusion

Digital droplet PCR is a sensitive molecular tool that enables low-level variant detection of PIK3CA in various tissue types, providing an alternative diagnostic method. Furthermore, urine cfDNA is a candidate biomarker for nephroblastomatosis in PROS, which may be useful to refine screening guidelines for tumor risk in these patients.

Vascular anomaly cases for the pediatric hematologist oncologists-An interdisciplinary review

Vascular anomalies (VAs) are classified as tumors or malformations depending on their clinical characteristics, pathological diagnosis, and genomic information. Diagnosis can be challenging because of the heterogeneity of clinical presentation; thus, the best diagnosis and care are provided by an interdisciplinary team of specialists. Over the past 10 years, an increasing number of pediatric hematologist/oncologists are caring for patients with VAs secondary to new medical therapy options and clinical trials. This paper focuses on complicated VA issues often seen by the pediatric hematologist/oncologist. The paper reviews clinical pearls on diagnosis, histology, radiology, and treatment options.

Sonographic screening for Wilms tumor in children with CLOVES syndrome

BACKGROUND

CLOVES syndrome is associated with somatic mosaic PIK3CA mutations and characterized by congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and skeletal anomalies. Wilms tumor (WT) is a malignant embryonal renal neoplasm associated with hemihypertrophy and certain overgrowth disorders. After identifying WT in a child with CLOVES, we questioned whether ultrasonographic screening was necessary in these patients.

METHODS

We retrospectively reviewed patients with CLOVES syndrome in our Vascular Anomalies Center at Boston Children's Hospital between 1998 and 2016 to identify those who developed WT. A PubMed literature search was also conducted to find other patients with both conditions.

RESULTS

A total of 122 patients with CLOVES syndrome were found in our database (mean age 7.7 years, range 0-53 years). Four patients developed WT; all were diagnosed by 2 years of age. The incidence of WT in our CLOVES patient population (3.3%) was significantly greater than the incidence of WT in the general population (1/10,000) (P < 0.001). Four additional patients with WT and CLOVES syndrome were identified in our literature review.

CONCLUSION

Patients with CLOVES syndrome have an increased risk of WT. Given the benefits of early detection and treatment, children with CLOVES syndrome should be considered for quarterly abdominal ultrasonography until age 7 years. Screening may be most beneficial for patients under 3 years of age.

Role of imaging in the diagnosis of parotid infantile hemangiomas

OBJECTIVES

To review the clinical presentation, imaging and follow-up of parotid infantile hemangiomas (IH).

METHODS

Over a 15-year period, all patients with a clinical diagnosis of parotid IH were evaluated. Imaging was available in 35. The medical records, photographs, and radiology studies of these patients were reviewed.

RESULTS

All patients presented at less than 4 months of age (M:F, 13:21). 19 (55)% of tumors were on the left and were bilateral in 2 patients. The majority (29 patients) presented due to localized swelling or palpable mass; the remainder had a cutaneous lesion, but no palpable mass at the time of presentation. The referring diagnosis was incomplete or incorrect in 9 patients (26%). The imaging studies all demonstrated a well-defined homogeneous mass, with no abnormality of the surrounding subcutaneous fat. Sonography showed a uniformly vascular lesion with pulsatile fast-flow seen on Doppler. On MRI, the lesion was hyperintense on T2-weighted images, isointense on T1, with intense enhancement post-contrast. Oral therapy (propranolol or corticosteroids) was prescribed in 15 (45%). Follow-up in 28 patients demonstrated stability of the lesion in 11, regression in size in 11 and complete involution in 6. After involution 2 patients underwent resection of residual tissue and/or excess skin.

CONCLUSIONS

Typical clinical presentation alone may be adequate to establish a diagnosis of parotid infantile hemangioma. However, in patients with no overlying cutaneous lesion, imaging can play a critical role in confirming the diagnosis. The sonographic findings are sufficiently characteristic to allow for a definitive diagnosis, obviating the need for further investigations. If diagnostic uncertainty remains or the full extent of the lesion cannot be appreciated, then MRI should be preferred over CT to avoid ionizing radiation.

Clinical case series of pediatric hepatic angiosarcoma

Hepatic angiosarcoma is a rare, aggressive, malignant neoplasm with fewer than 50 cases reported in children. Prognosis is poor, with a minority surviving beyond 2 years after diagnosis. We report eight cases of pediatric hepatic angiosarcoma, diagnosed at a mean age of 3 years. Seven were initially diagnosed with an infantile hepatic hemangioendothelioma (IHHE) or hemangioma and the eighth with a "vascular tumor." Two patients, who received liver transplant, survived. We suggest hepatic hemangiomas can rarely transform into angiosarcomas and a subset of IHHEs (Type II) are actually a low-grade form of angiosarcoma rather than a benign lesion.

Late sequelae and long-term outcomes of vascular anomalies

Vascular anomalies are classified as tumors and malformations depending on their clinical characteristics, pathological diagnosis and recent genomic information. Diagnosis can still be challenging because of the heterogeneity of clinical presentation. Thus, the best care is provided by an interdisciplinary team of specialists. An updated classification system has helped provide more consistent terminology with the addition of new diagnoses and genomic discovery. Historically, treatment of vascular anomalies was primarily surgical and or interventional with limited medical therapies. The field of vascular anomalies lacked prospective clinical trials in both medical treatments as well as surgical and interventional therapeutic options. Recent interdisciplinary collaboration has led to collaborative studies in which short- and long-term outcomes are being prospectively evaluated. Specifically, discoveries of pharmacologic agents effective in treating vascular anomalies have broadened our medical therapeutic options, which has led to innovative approaches in combined treatment of vascular anomalies and has stressed the need to prospectively assess long-term outcomes and sequelae for these patients which has been lacking in this field.