Jeremy A. Goss

Somatic MAP2K1 Mutations Are Associated with Extracranial Arteriovenous Malformation

Arteriovenous malformation (AVM) is a fast-flow, congenital vascular anomaly that may arise anywhere in the body. AVMs typically progress, causing destruction of surrounding tissue and, sometimes, cardiac overload. AVMs are difficult to control; they often re-expand after embolization or resection, and pharmacologic therapy is unavailable. We studied extracranial AVMs in order to identify their biological basis. We performed whole-exome sequencing (WES) and whole-genome sequencing (WGS) on AVM tissue from affected individuals. Endothelial cells were separated from non-endothelial cells by immune-affinity purification. We used droplet digital PCR (ddPCR) to confirm mutations found by WES and WGS, to determine whether mutant alleles were enriched in endothelial or non-endothelial cells, and to screen additional AVM specimens. In seven of ten specimens, WES and WGS detected and ddPCR confirmed somatic mutations in mitogen activated protein kinase kinase 1 (MAP2K1), the gene that encodes MAP-extracellular signal-regulated kinase 1 (MEK1). Mutant alleles were enriched in endothelial cells and were not present in blood or saliva. 9 of 15 additional AVM specimens contained mutant MAP2K1 alleles. Mutations were missense or small in-frame deletions that affect amino acid residues within or adjacent to the proteins negative regulatory domain. Several of these mutations have been found in cancers and shown to increase MEK1 activity. In summary, somatic mutations in MAP2K1 are a common cause of extracranial AVM. The likely mechanism is endothelial cell dysfunction due to increased MEK1 activity. MEK1 inhibitors, which are approved to treat several forms of cancer, are potential therapeutic agents for individuals with extracranial AVM.

Higher Dosages of BMP-2 in Alveolar Cleft Repair Result in Higher Rates of Postoperative Nasal Stenosis.

CONCLUSIONS: Here we demonstrate that BMP/DBM is equivalent at 6-9 months to iliac crest grafts, in terms of bone fill within the alveolar cleft site and overall regenerated bone density. These CBCT data contradict the conclusions that are drawn from occlusal radiographs alone; complete bony reconstitution as measured by the Bergland scale on 2D radiographs is unlikely to correlate with true obliteration of the cleft site, as the postoperative CBCT images at 6-9 months show significant bone gaps within the space. This study is the first to apply 3D imaging to understand bone regeneration in the context of secondary alveolar cleft repair. Higher Dosages of BMP-2 in Alveolar Cleft Repair Result in Higher Rates of Postoperative Nasal Stenosis

Diagnosis and Staging of Lymphedema

Lymphedema often is confused with other causes of extremity edema and enlargement. Understanding the risk factors and physical examination signs of lymphedema can enable the health care practitioner to accurately diagnose patients ∼90% of the time. Confirmatory diagnosis of the disease is made using lymphoscintigraphy. It is important to correctly diagnose patients with lymphedema so that they can be managed appropriately.

Abstract 85: Somatic MAP2K1 Mutations in Arteriovenous Malformation Constitutively Activate the RAS/MAPK Pathway

tissue growth factor (CTGF) and myofibroblast alpha smooth muscle actin (α-SMA) protein production by Western blot as well as immunofluorescence and validated at the mRNA level by Quantitative PCR. Activation of the TGF-β pathway was determined by measuring the TGF-β receptor 1 (ALK5) and phosphorylated Smad2/3 levels by using Western blot and immunofluorescence. Luciferase assay was used to measure nAG protein’s capacity to inhibit the thee TGF-β isomers. Cell migration was assessed using a scratch assay and finally colocalization of nAG protein with TGFβ receptor 1 was evaluated using confocal microscopy.

Abstract: Primary Lymphedema of the Upper Extremity

Suday, Sptem er 0, 2018 RESULTS: The vascular volume in the VEGF and PDGF-treated group (164 mm3) was significantly higher compared to the control group (88 mm3, p=0,003) and the untreated contralateral sides (36 mm3, p=0,016). The inner cortex showed significantly more bone remodeling in the VEGF and PDGF treated group compared to the control group (Bone Formation Rate: 557 μm3/ μm3/ jaar versus 403 μm3/μm3/jaar, p=0,013). Compared to the untreated contralateral side the VEGF-group showed no significant difference (Bone Formation Rate: 557 μm3/μm3/jaar versus 80 μm3/μm3/ jaar, p=0,109). The Sanderson’s rapid bone stains showed significant higher numbers for osteoblasts in the inner cortex (224) compared to the control group (119, p=0.007), osteoid surface (45mm2 versus 26mm2, p=0.015) and eroded surface (11mm2 versus 5mm2, p=0.015), but not for osteoclast number (7 versus 7, p=0.800).

Association between extremity kaposiform hemangioendothelioma and lymphedema

Kaposiform hemangioendotheliomas are pediatric vascular tumors that do not metastasize. We present a patient with a thigh kaposiform hemangioendothelioma successfully treated using a systemic corticosteroid during infancy who was diagnosed with lymphedema in the extremity 9 years later. The observation that extremity kaposiform hemangioendothelioma could possibly be associated with lymphedema has implications for the care of patients with kaposiform hemangioendothelioma.

Congenital Vascular Tumors

Vascular tumors are benign neoplasms, which result from proliferating endothelial cells. These lesions present during infancy or childhood, may affect any location, and exhibit postnatal growth. Local complications include bleeding, tissue destruction, and pain whereas systemic sequelae include thrombocytopenia, congestive heart failure, and death. Vascular tumors should be differentiated from vascular malformations, which present at birth, have a quiescent endothelium, and grow in proportion to the child. Together, vascular tumors and malformations comprise the field of vascular anomalies.

Primary Lymphedema of the Upper Extremities: Clinical and Lymphoscintigraphic Features in 23 Patients

BACKGROUND Primary idiopathic lymphedema is an uncommon condition that typically affects the lower extremities. Patients have a malformed lymphatic system that causes subcutaneous fluid and adipose deposition. Rarely, the disease also has been described in the upper extremities. The purpose of this study was to investigate a cohort of patients with primary arm lymphedema to better understand the disease. METHODS Patients evaluated in our Lymphedema Program between 2008 and 2018 were reviewed for individuals with upper extremity primary lymphedema. Gender, age of onset, morbidity, associated features, and management were identified. Transit of radiolabeled tracer and dermal backflow on lymphoscintigraphy were recorded. RESULTS Twenty-three patients of 234 individuals with primary lymphedema had upper extremity disease (9.8%). Eleven subjects were male. Age of onset was infancy (n = 15), adolescence (n = 5), or adulthood (n = 3). The disease affected the left arm (n = 11), right arm (n = 9), or both upper extremities (n = 3). Lymphoscintigraphy in 15 patients exhibited delayed transit of tracer and 2 illustrated dermal backflow. One-half of individuals also had primary lower extremity lymphedema (six unilateral and six bilateral). None of the patients in the cohort exhibited a family history of lymphedema. Two individuals had Turner syndrome. Morbidity included infection (n = 5), other lymphatic anomalies (n = 6), and lymphangiosarcoma (n = 1). CONCLUSIONS The upper extremities are a rare location for primary lymphedema and patients often also have lymphedema of the legs. Compared with that of the lower extremities, primary disease of the arm is more likely to be associated with systemic lymphatic dysfunction and has a lower risk of familial transmission.

Association of Somatic GNAQ Mutation With Capillary Malformations in a Case of Choroidal Hemangioma

Importance Choroidal hemangiomas are defined by a thickened choroid owing to vessel overgrowth, which may increase the intraocular pressure and lead to glaucoma. Choroidal hemangioma and glaucoma often co-occur in patients with Sturge-Weber syndrome, a rare neurocutaneous disorder characterized by capillary malformations. Objective To determine whether the mutation found in most capillary malformations, GNAQ R183Q (c.548G>A), was present in the choroidal hemangioma of a patient with Sturge-Weber syndrome. Design, Setting, and Participant Using laser-capture microdissection, choroidal blood vessels were isolated from paraffin-embedded tissue sections, and genomic DNA was extracted for mutational analysis. Choroidal sections were analyzed in parallel. A patient with choroidal hemangioma and Sturge-Weber syndrome who had undergone enucleation was analyzed in this study at Boston Children’s Hospital. Negative controls were choroidal tissue from an eye with retinoblastoma and unaffected lung tissue; brain tissue from a different patient with Sturge-Weber syndrome served as a positive control. Infantile hemangioma was analyzed as well. Data were analyzed in 2018. Main Outcomes and Measures The mutant allelic frequency of GNAQ R183 and GNAQ Q209L/H/P was determined by droplet digital polymerase chain reaction on isolated genomic DNA. The infantile hemangioma marker glucose transporter-1 was visualized by immunofluorescent staining of tissue sections. Results The GNAQ R183Q mutation was present in the patient’s choroidal vessels (21.1%) at a frequency similar to that found in brain tissue from a different patient with Sturge-Weber syndrome (25.1%). In contrast, choroidal vessels from a case of retinoblastoma were negative for the mutation (0.5%), as was lung tissue (0.2%). The patient’s choroidal tissue was negative for the 3 GNAQ mutations associated with congenital hemangioma and for the infantile hemangioma marker glucose transporter-1. Conclusions and Relevance The results suggest that a more accurate description for choroidal hemangioma in patients with Sturge-Weber syndrome is choroidal capillary malformation. This finding may explain why propranolol, used to treat infantile hemangiomas, has been largely ineffective in patients with choroidal hemangioma. Further studies are needed to corroborate this finding.

Resolution of Primary Lymphedema: A Case Report

Summary: Primary lymphedema is a rare, progressive disease that typically affects the lower extremity. The condition is not curable, and the limb enlarges over time because of subcutaneous fibroadipose deposition. We present a patient with clinical and radiographical evidence of resolution of primary lymphedema. This observation may provide greater insight into the pathophysiology of the disease.