Extracranial vascular malformations (hemangiomas and vascular malformations) in children and adolescents - diagnosis, clinic, and therapy

Mural Cells Initiate Endothelial-to-Mesenchymal Transition in Adjacent Endothelial Cells in Extracranial AVMs

Extracranial arteriovenous malformations (eAVMs) are complex vascular lesions characterized by anomalous arteriovenous connections, vascular instability, and disruptions in endothelial cell (EC)-to-mural cell (MC) interactions. This study sought to determine whether eAVM-MCs could induce endothelial-to-mesenchymal transition (EndMT), a process known to disrupt vascular integrity, in the eAVM microenvironment. eAVM and paired control tissues were analyzed using RT-PCR for EC (CD31, CD34, and CDH5) and EndMT-specific markers (SNAI1, SNAI2, ACTA2/α-SMA, N-cadherin/CDH2, VIM). Immunohistochemistry (IHC) was also performed to analyze MC- (PDGFR-β and α-SMA), EC (CD31, CD34, and CDH5), and EndMT-specific markers (CDH2 and SNAI1) in sequential paraffin-embedded sections of eAVM patient biopsies and in adjacent normal tissue biopsies from the same patients. Furthermore, eAVM-MCs and MCs from normal paired tissues (NMCs) were then isolated from fresh human surgical samples using flow cytometry and co-cultured with normal human umbilical vein vascular endothelial cells (HUVECs), followed by analysis of CD31 by immunofluorescence. RT-PCR analysis did not show a significant difference in the expression of EC markers between eAVM tissues and controls, whereas expression of EndMT-specific markers was upregulated in eAVM tissues compared to controls. IHC of eAVMs and paired control tissues demonstrated regions of significant perivascular eAVM-MC expansion (PDGFR-β+, and α-SMA+) surrounding dilated, morphologically abnormal vessels. These regions contained endothelium undergoing EndMT as evidenced by loss of CD31, CD34, and CDH5 expression and upregulation of the EndMT-associated genes CDH2 and SNAI1. Isolated eAVM-MCs induced loss of CD31 in HUVECs when grown in co-culture, while NMCs did not. This study suggests that the eAVM endothelium surrounded by expanded eAVM-MCs undergoes EndMT, potentially leading to the formation of dilated and fragile vessels, and implicates the eAVM-MCs in EndMT initiation and eAVM pathology.

Percutaneous injection of sclerosant agents as an effective treatment for cystic malformations of the head and neck

PURPOSE

To evaluate the clinical and aesthetic outcome of percutaneous injection of sclerosant agents to treat head and neck cystic malformations (HNCM) and to assess their recurrence rate based on histology and site.

METHODS

Fifty-four subjects (mean age 46 years) with HNCM treated by percutaneous injection of sclerosant agents between January and December 2017 were included. Imaging and clinical data before and after the procedure were collected. Quality of Life Index, Pain Visual Analogue Scale, and Aesthetic Scale scores were measured to assess clinical and aesthetic outcomes. A size reduction of ≥ 70% assessed through the visual scale was considered significant.

RESULTS

Of the 54 HNCM, there were 26 (48%) lymphatic malformations (LM), 13 (24%) salivary epithelial duct cysts of the parotid gland, 12 (22%) salivary mucoceles, and 3 (5%) branchial cysts. A significant size reduction and a satisfactory clinical-aesthetic outcome were observed in all types of LM. The number of reinterventions was significantly associated with the number of lesions (p < 0.001). The lowest number of interventions was observed in macrocystic lymphatic malformations (average of 1.2 interventions). All salivary epithelial duct cysts showed a significant reduction in size, a satisfactory clinical-aesthetic outcome, and an average of 1.16 interventions per patient. Mucoceles had a worse response, with only 3/14 patients showing a satisfactory and long-lasting clinical outcome (average of 1.16 interventions). Treatment of branchial cysts showed the worst outcome with a limited clinical response (3/3).

CONCLUSION

Percutaneous injection of sclerosant agents may be considered as a first-line treatment for LM and salivary epithelial duct cysts.

Prevalence and clinical features of orbital vascular anomalies in children

PURPOSE

To report the prevalence, clinical characteristics, and natural history of orbital vascular anomalies diagnosed among children over a 50-year period.

METHODS

The medical records of all patients <19 years diagnosed with any form of an orbital vascular anomaly (OVA) at Mayo Clinic, Rochester, Minnesota from January 1 1966, through December 31 2015, were retrospectively reviewed.

RESULTS

A total of 109 children were diagnosed with OVA during the 50-year period, of which 24 were from Olmsted County, MN, yielding a birth prevalence of 1 in 4,305 live births. The median age at diagnosis for the 109 patients was 1.2 years (range, 0-17.9 years) and 67 (61.5%) were female. Common presenting symptoms included proptosis in 80 (73.4%) patients, abnormalities in skin color in 45 (41.3%) patients, and pain in 18 (16.5%) patients. There were 55 (50.5%) vascular malformations [50 (91%) low-flow lymphatic malformations, 3 (5.5%) high-flow arteriovenous malformations, and 2 (3.5%) low-flow venous malformations] and 54 (49.5%) vascular tumors [53 (98%) capillary hemangiomas and 1 (2%) kaposiform hemangioendothelioma]. During a mean follow-up of 5.95 years (range 0-27.7 years), amblyopia and/or strabismus were diagnosed in 46 (43.4%) patients.

CONCLUSIONS

Capillary hemangiomas and low-flow lymphatic malformations comprise most of the orbital vascular anomalies in this cohort of children. Amblyopia and strabismus are common sequelae, highlighting the importance of early diagnosis and appropriate management.

Cystic hygroma of the neck - case report

Cystic hygromas (CHs) are benign congenital malformations of the lymphatic system mainly diagnosed in small children aged less than two years old. They may give a multitude of local, sometimes severe complications. The most used method of treatment is surgical removal. In this paper, we present the case of a CH of a 13-year-old boy, localized in the right lateral region of the neck, diagnosed through magnetic resonance imaging (MRI), with excellent results of the surgical treatment.

Stemness-Associated Markers Are Expressed in Extracranial Arteriovenous Malformation

Objectives: Arteriovenous malformation (AVM) consists of a nidus with poorly formed low-resistance vessels in place of a functional capillary network. The role of somatic mutations in embryonic stem cells (ESCs) and vascular anomalies and the presence of primitive populations in vascular anomalies led us to investigate the presence of a primitive population in extracranial AVM.

Methods: Extracranial AVM tissue samples from 12 patients were stained for stemness-associated markers OCT4, SOX2, NANOG, KLF4, and c-MYC using immunohistochemical staining. In situ hybridization (ISH) was performed on six tissue samples to determine transcript expression. Western blotting and RT-qPCR were performed on two AVM-derived primary cell lines to determine protein and transcript expression of these markers, respectively. Immunofluorescence staining was performed on two tissue samples to investigate marker co-localization.

Results: Immunohistochemical staining demonstrated the expression of OCT4, SOX2, KLF4, and c-MYC on the endothelium and media of lesional vessels and cells within the stroma of the nidus in all 12 AVM tissue samples. ISH and RT-qPCR confirmed transcript expression of all five markers. Western blotting showed protein expression of all markers except NANOG. Immunofluorescence staining demonstrated an OCT4+/SOX2+/KLF4+/c-MYC+ population within the endothelium and media of the lesional vessels and cells within the stroma of the AVM nidus.

Conclusions: Our findings may suggest the presence of a primitive population within the AVM nidus. Further investigation may lead to novel therapeutic targeting of this population.

Subcutaneous hemangioma on nasal dorsum: a case report

INTRODUCTION

Hemangioma is a benign tumor made up of blood vessels and typically occurs as a slightly elevated purplish or reddish area of skin. Hemangioma is mostly found superficially; subcutaneous hemangioma in the nasal dorsum is rare.

CASE PRESENTATION

In West Nusa Tenggara Regional Hospital, the authors found two cases of subcutaneous hemangioma in patients of very different ages. The first patient was a 2-year-old Sasak girl, and the other was a 40-year-old Sasak man. The pediatric patient was treated with an elliptical approach, whereas the adult patient was treated with lateral rhinotomy extended by an elliptical approach to remove the hemangioma and ligate the feeding arteries. After surgery, the adult patient was followed up for 5 months, whereas the pediatric patient was followed up for 3 months. The results for both patients were good, with minimal scar formation.

CONCLUSION

Despite the limitations of technology and human resources in a remote area of Indonesia, the surgical approach used in these cases produced good outcomes for both patients.

Arteriovenous Malformations: Syndrome Identification and Vascular Management

PURPOSE OF REVIEW

Vascular malformations represent a poorly understood set of conditions that create considerable diagnostic and therapeutic confusion. Historically, extensive surgical resections yielded poor results. More recently, the treatment paradigm has shifted to endovascular therapy such that embolization and sclerotherapy are now considered the first line of treatment. Although there is still a role for traditional surgical techniques, it is now most commonly integrated with endovascular therapies in a hybrid fashion. The goal of this review is to provide a greater understanding of the diagnosis and treatment of vascular malformations.

RECENT FINDINGS

Vascular malformations can be high-flow (arteriovenous shunting) or low-flow (venous or lymphatic). Clinical presentation and treatment is different for each. Treatment of high-flow lesions must be directed at reducing or eliminating the nidus, usually via super-selective catheterization and embolization. Low-flow lesions are usually treated by direct injection of sclerosing agents under fluoroscopic or ultrasound guidance. The cornerstone of managing patients with vascular malformations is making the proper diagnosis, which is often challenging. Even after a diagnosis is made, therapy itself may be challenging and generate frustration among patients and providers. Frequently, the treatment of vascular malformations is characterized by only slow and incremental improvements without complete lesion eradication. By combining a thorough understanding of the vascular malformation disease process with an array of endovascular techniques, vascular interventionalists may contribute greatly to the care of these patients.