Childhood Vascular Tumors Research Articles

MEK inhibition reduced vascular tumor growth and coagulopathy in a mouse model with hyperactive GNAQ

Activating non-inherited mutations in the guanine nucleotide-binding protein G(q) subunit alpha (GNAQ) gene family have been identified in childhood vascular tumors. Patients experience extensive disfigurement, chronic pain and severe complications including a potentially lethal coagulopathy termed Kasabach-Merritt phenomenon. Animal models for this class of vascular tumors do not exist. This has severely hindered the discovery of the molecular consequences of GNAQ mutations in the vasculature and, in turn, the preclinical development of effective targeted therapies. Here we report a mouse model expressing hyperactive mutant GNAQ in endothelial cells. Mutant mice develop vascular and coagulopathy phenotypes similar to those seen in patients. Mechanistically, by transcriptomic analysis we demonstrate increased mitogen activated protein kinase signaling in the mutant endothelial cells. Targeting of this pathway with Trametinib suppresses the tumor growth by reducing vascular cell proliferation and permeability. Trametinib also prevents the development of coagulopathy and improves mouse survival.

Childhood Vascular Tumors.

Vascular tumors in pediatric patients are an important entity for the clinician to recognize and correctly diagnose. They may present at birth or develop at any point during infancy, childhood, or adolescence. Most are benign, but even benign lesions may have significant morbidity without proper intervention. Malignant vascular tumors are also rarely seen in the pediatric population, and may be associated with various syndromes.

Effects of propranolol therapy in Moroccan children with infantile hemangioma

Infantile hemangiomas are the most common childhood vascular tumors. Propranolol is a β-adrenergic blocker that has proven effective in the treatment of this tumor. Numerous studies around the world have been published, describing satisfactory responses in pediatric populations with a higher cure rate and fewer adverse effects than when using corticosteroids. The aim of this study was to evaluate the efficacy and adverse effects of propranolol in Moroccan pediatric patients diagnosed with infantile hemangioma who were treated with oral propranolol. A prospective study was conducted from May 2009 to May 2017 in the department of dermatology of a hospital in Casablanca. All the patients who had infantile hemangioma were included. The study comprised 121 patients with infantile hemangioma: 90 girls and 31 boys. The mean age was 6 months. The majority of hemangiomas were mixed (63%) and located on the face and neck. The treatment was well tolerated by all the patients. The dosage of propranolol was gradually increased from 1mg to 2mg/kg/day. We noted a decrease in coloration after 48hours. The healing period for ulcerated hemangiomas was 20 days. A decrease in size was noted after 1 month, while a decrease in palpebral obstruction occurred after 3 days. Treatment with propranolol in this group of Moroccan pediatric patients proved to be safe and effective at a dose of 2 mg/kg/day, reducing the size and coloration of the hemangioma. Treatment should be stopped at an appropriate time, which is determined primarily by the lesion regression rate after propranolol treatment.

GNA14 Somatic Mutation Causes Congenital and Sporadic Vascular Tumors by MAPK Activation

Vascular tumors are among the most common neoplasms in infants and children; 5%-10% of newborns present with or develop lesions within the first 3months of life. Most are benign infantile hemangiomas that typically regress by 5 years of age; other vascular tumors include congenital tufted angiomas (TAs), kaposiform hemangioendotheliomas (KHEs), and childhood lobular capillary hemangiomas (LCHs). Some of these lesions can become locally invasive and unresponsive to pharmacologic intervention, leading to significant complications. Recent investigation has revealed that activating mutations in HRAS, KRAS, NRAS, GNAQ, and GNA11 can cause certain types of rare childhood vascular tumors, and we have now identified causal recurrent somatic activating mutations in GNA14 by whole-exome and targeted sequencing. We found somatic activating GNA14 c.614A>T (p.Gln205Leu) mutations in one KHE, one TA, and one LCH and a GNA11 c.547C>T (p.Arg183Cys) mutation in two LCH lesions. We examined mutation pathobiology via expression of mutant GNA14 or GNA11 in primary human endothelial cells and melanocytes. GNA14 and GNA11 mutations induced changes in cellular morphology and rendered cells growth-factor independent by upregulating the MAPK pathway. Our findings identify GNA14 mutations as a cause of childhood vascular tumors, offer insight into mechanisms of oncogenic transformation by mutations affecting Gaq family members, and identify potential targets for therapeutic intervention.

Therapeutic Effect of Propranolol in Mexican Patients with Infantile Hemangioma.

BackgroundInfantile hemangiomas are the most common childhood vascular tumors, occurring in 10 % of children aged less than 1 year. Propranolol, a β-adrenergic blocker mainly indicated for hypertension, has proven effective in treating these types of tumors.ObjectiveTo evaluate the efficacy and adverse effects of propranolol in Mexican pediatric patients diagnosed with infantile hemangioma, treated with an extemporaneously compounded solution of propranolol.MethodsAn open prospective observational study at the Children’s Hospital of the Californias in Tijuana, Mexico was performed on ambulatory pediatric patients between the ages of 3 and 12 months diagnosed with infantile hemangioma. Patients were treated with an oral solution of propranolol in doses ranging from 0.5 to 2.5 mg/kg/day. Children were monitored monthly by the physician in charge, at which time clinical and treatment data were collected.ResultsOver a period of 20 months, 31 patients were treated (36 % male and 64 % female).The majority of hemangiomas were superficial (55 %), located mainly on the face. Treatment had an average duration of 10.5 months. Ninety-six percent responded to the treatment, showing decreases in size and coloration of the hemangioma. Children who started therapy before 5 months of age had a significantly better response and shorter duration of treatment. The average therapeutic dose was 1.5 mg/kg/day. Five patients experienced mild adverse effects during the first month of therapy.ConclusionTreatment with propranolol in this group of Mexican pediatric patients proved to be safe and effective at an average dose of 1.5 mg/kg/day, reducing the size and coloration of hemangioma with a minimum incidence of adverse effects.

Beta-blockers for childhood vascular tumors.

Since 2008, beta-blockers have become first-line treatment for infantile hemangiomas, the most common tumor of infancy. Their role is also being explored in the treatment of other childhood vascular tumors. Recent research has demonstrated that propranolol is a more effective and safer treatment for infantile hemangiomas than previous therapeutic options. It is most effective when initiated during the tumor's proliferative phase. Other oral beta-blockers such as atenolol and nadolol are less studied, but may offer similar efficacy. Topical beta-blockers such as timolol appear to be effective in treating small, superficial infantile hemangiomas. Beta-blockers have shown variable results for the treatment of other vascular tumors of childhood, such as pyogenic granulomas, kaposiform hemangioendotheliomas, and tufted angiomas. Propranolol has revolutionized the treatment of infantile hemangiomas, and other beta-blockers provide promising alternatives. Unanswered questions remain about the optimal choice of agent, delivery mechanism, dosage, need for pretreatment evaluation or ongoing monitoring, and duration of therapy. The role of beta-blockers in treating other types of vascular tumors requires further study.

Beta blocker treatment for infantile hemangiomas

Infantile hemangiomas (IH) are common childhood vascular tumors. Treatment of IH has undergone rapid change in recent years. Since 2008, oral propranolol has been used to treat complicated IH and has proven superior to previously used therapies. More recently, the efficacy of other systemic beta blockers, specifically atenolol and nadolol, has been reported. In addition, topical timolol solution has been effective for treatment of smaller, more superficial IH. The purpose of this article is to review the current literature of beta-blocker therapy for IH.

Classification des anomalies vasculaires superficielles

All superficial vascular abnormalities are not angiomas even though this term continues - incorrectly - to be used. Because the suffix "oma" implies a tumor, it is necessary to differentiate true vascular tumors, such as infantile hemangioma, from vascular malformations. From a hemodynamic perspective, there are two types of vascular malformations: slow- and fast-flow. In addition to the functioning of the impaired or severely damaged vessels, we discuss slow-flow capillary, venous, or lymphatic malformations and rapid flow arterial and arteriovenous malformations. All combinations are possible. There are several types of childhood vascular tumors with different courses and different prognoses. Infantile hemangioma is by far the most frequent (8 to 10 children/100). The diverse other vascular tumors in children are sufficiently rare that they are described as orphan diseases. Since the end of the last century, a simple endothelial marker, GLUT-1, is available. This immunophenotype is present in all cases of infantile hemangioma at every stage and is negative in other tumors. Kasabach-Merritt syndrome and its accompanying severe thrombocytopenia never complicate childhood hemangioma, contrary to what has been said for nearly 60 years. When it is present, the tumor is either a tufted angioma or kaposiform hemangioendothelioma, and the GLUT1 marker can distinguish them from infantile hemangioma if the histologic diagnosis is uncertain (GLUT 1 is negative in both the latter cases). There are a wide variety of rare vascular tumors; many of them are benign, isolated, or limited; some are locally aggressive and recur after excision. A small number are low-grade malignant lesions with a risk of multivessel expansion, metastasis, and sometimes a fatal outcome. Major progress has been made in the imaging of these vascular abnormalities. Magnetic resonance imaging (MRI) in particular has revolutionized the non-invasive and especially the non-irradiating exploration of many of them. It provides information about the extent of the lesion and allows an etiological approach in many cases. Moreover, neuroradiologic evaluation of vascular cerebromeningeal lesions benefits not only from the now-standard diagnostic neurologic imaging methods of CT and MRI, but also from various advances in the techniques of functional imaging. Accordingly, for Sturge-Weber syndrome, functional imaging provides hope for an early prognosis, in particular cognitive, when these techniques are more widely used (SPECT, PET, especially the new advanced sequences of perfusion in MRI-DTI). Chronic - indeed lifelong - coagulation abnormalities, with phases of aggravation, occur in approximately half of the patients with venous malformations of the trunk and limbs, and more rarely in neck and face sites. This is not without consequences, but also not without therapeutic solutions: screening for it is therefore essential (measurement of dimer and fibrinogen levels). The discovery of gene mutations at the origin of some familial vascular malformations provides complementary data for the current classification of vascular abnormalities. It suggests that targeted therapy may be possible but probably not for quite a bit longer.

Kaposiform hemangioendothelioma of the mediastinum in a 7-month-old boy: a case report

Kaposiform hemangioendothelioma is an aggressive vascular proliferation that has been recognized as a separate entity from other childhood vascular tumors. The authors present an unusual case of hemangioendothelioma arising in the mediastinum of a 7-month-old male infant with acute respiratory distress and Kasabach-Merritt syndrome. This patient with life-threatening lesion showed a dramatic response to interferon alfa-2a. This case had many histologic and clinical features consistent with kaposiform hemangioendothelioma.

Papillary intralymphatic angioendothelioma (PILA): a report of twelve cases of a distinctive vascular tumor with phenotypic features of lymphatic vessels.

Six childhood vascular tumors were designated as "malignant endovascular papillary angioendothelioma" by Dabska in 1969. Since then, a few reports of similar cases were published, often called "Dabska tumors." Twelve similar cases were identified in review of vascular tumors from the authors' institutions. There were five men and seven women, including seven adults. Patient ages ranged from 8 to 59 years (mean, 30 years). The tumors occurred in the dermis or subcutis of the buttocks or thigh (n = 6), thumb or hand (n = 3), abdomen (n = 2), and heel (n = 1). The tumor sizes ranged from 1 to more than 40 cm (mean, 7.0 cm). The unifying feature of all cases was distinctive intravascular growth of well-differentiated endothelial cells presenting as a matchstick columnar configuration, sometimes with a large production of matrix that was positive for collagen type IV. In half the cases, these intravascular proliferations had an associated actin-positive pericytic proliferation. There was minimal cytologic atypia and rare to absent mitotic activity. Two cases had an adjacent lymphangioma, and two additional cases had clusters of lymphatic vessels adjacent to the tumor. All but two of the cases showed varying degrees of stromal or intraluminal lymphocytes. Occasional epithelioid endothelial cells were seen, but no cases had features typical of epithelioid, spindle cell, or retiform hemangioendothelioma. Tumor cells were positive for vimentin, von Willebrand factor, CD31, and focally for CD34 and were negative for keratins, epithelial membrane antigen, S-100 protein, and desmin. Vascular endothelial cell growth factor receptor type 3, a recently introduced marker for lymphatic endothelia, was positive in all eight cases that were studied, supporting a lymphatic phenotype. Follow-up in 8 of the 12 cases showed no evidence of recurrences, metastases, or residual disease during follow-ups ranging from 1 to 17 years (mean, 9 years). Based on the proliferative borderline features and the lymphatic phenotype, we propose to designate these tumors as papillary intralymphatic angioendothelioma. Additional cases with extensive follow-up should be studied to rule out variants with malignant potential.