Javier A. Couto

Mammalian target of rapamycin pathway mutations cause hemimegalencephaly and focal cortical dysplasia

Focal malformations of cortical development, including focal cortical dysplasia (FCD) and hemimegalencephaly (HME), are important causes of intractable childhood epilepsy. Using targeted and exome sequencing on DNA from resected brain samples and nonbrain samples from 53 patients with FCD or HME, we identified pathogenic germline and mosaic mutations in multiple PI3K/AKT pathway genes in 9 patients, and a likely pathogenic variant in 1 additional patient. Our data confirm the association of DEPDC5 with sporadic FCD but also implicate this gene for the first time in HME. Our findings suggest that modulation of the mammalian target of rapamycin pathway may hold promise for malformation‐associated epilepsy. Ann Neurol 2015;77:720–725

Endothelial Cells from Capillary Malformations Are Enriched for Somatic GNAQ Mutations.

Background: A somatic mutation in GNAQ (c.548G>A; p.R183Q), encoding G&agr;q, has been found in syndromic and sporadic capillary malformation tissue. However, the specific cell type containing the mutation is unknown. The purpose of this study was to determine which cells in capillary malformations have the GNAQ mutation. Methods: Human capillary malformation tissue was obtained from 13 patients during a clinically indicated procedure. Droplet digital polymerase chain reaction, capable of detecting mutant allelic frequencies as low as 0.1 percent, was used to quantify the abundance of GNAQ mutant cells in capillary malformation tissue. Six specimens were fractionated by fluorescence-activated cell sorting into hematopoietic, endothelial, perivascular, and stromal cells. The frequency of GNAQ mutant cells in these populations was quantified by droplet digital polymerase chain reaction. Results: Eight capillary malformations contained GNAQ p.R183Q mutant cells, two lesions had novel GNAQ mutations (p.R183L and p.R183G), and three capillary malformations did not have a detectable GNAQ p.R183 mutation. Mutant allelic frequencies ranged from 2 to 11 percent. Following fluorescence-activated cell sorting, the GNAQ mutation was found in the endothelial but not the platelet-derived growth factor receptor-&bgr;–positive cell population; mutant allelic frequencies were 3 to 43 percent. Conclusion: Endothelial cells in capillary malformations are enriched for GNAQ mutations and are likely responsible for the pathophysiology underlying capillary malformation.

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.

mTOR Pathway Mutations Cause Hemimegalencephaly and Focal Cortical Dysplasia

Focal malformations of cortical development, including focal cortical dysplasia (FCD) and hemimegalencephaly (HME), are important causes of intractable childhood epilepsy. Using targeted and exome sequencing on DNA from resected brain samples and nonbrain samples from 53 patients with FCD or HME, we identified pathogenic germline and mosaic mutations in multiple PI3K/AKT pathway genes in 9 patients, and a likely pathogenic variant in 1 additional patient. Our data confirm the association of DEPDC5 with sporadic FCD but also implicate this gene for the first time in HME. Our findings suggest that modulation of the mammalian target of rapamycin pathway may hold promise for malformation‐associated epilepsy. Ann Neurol 2015;77:720–725

Management of problematic infantile hemangioma using intralesional triamcinolone: Efficacy and safety in 100 infants

BACKGROUND Intralesional corticosteroid is one method used to limit the rapid growth of infantile hemangiomas. The purpose of this study was to determine the efficacy and safety of triamcinolone injection using a standardized protocol. METHODS The study comprised infants managed with intralesional corticosteroid between 2007 and 2013. Tumors ≤3 cm in diameter were injected with triamcinolone, not to exceed 3 mg/kg, and followed every 4-6 weeks to determine whether additional injections were indicated. Predictive variables were patient age and tumor location, depth, and size. Treatment response was defined as regression, stabilization, or failure. Rebound growth and drug morbidity were recorded. RESULTS Seventy-three females and 27 males had lesions located on the lip (29%), cheek (20%), nose (16%), periorbital area (13%), forehead (7%), scalp (4%), chin (2%), ear (2%), trunk (2%), extremity (2%), and neck (2%). Mean tumor size was 2.1 cm(2) (range 0.15-9.0). Treatment began at an average age of 11 weeks (range 3-30). The mean number of injections was 1.8 (range 1-5), and the average dose per injection was 1.6 mg/kg (range 0.76-2.66). All tumors responded: 63% regressed and 37% stabilized. Rebound growth affected 40% of tumors at a median of 3 weeks (IQR 3-4) following injection. Age, location, size, and depth did not affect treatment response (p = 0.7). None of the patients exhibited systemic side-effects and 2% had atrophy at the site of injection. CONCLUSION Intralesional triamcinolone is an effective treatment for small, localized proliferating infantile hemangiomas. Therapy is safe and infants are at minimal risk for systemic side-effects when low doses of corticosteroid are used.

Facial Infiltrating Lipomatosis Contains Somatic PIK3CA Mutations in Multiple Tissues.

72 Figure 1. Histologic analysis with haematoxylin-eosin (H+E). In M+PRP groıp, all epidermal layers were clearly organized and the junction between epidermis and dermis was shown in obviously. Neoangiogenesis was seen in dermal layer (arrows). And inflammatory cells were realized in endovascular area of dermal and hypodermal layers (arrowhead). Also, connective tissue was more organized compare than the other groups of epidermal and dermal area (double arrowheads figure L,M).

Management of Vascular Anomalies and Related Conditions Using Suction-Assisted Tissue Removal.

Summary: Vascular anomalies and related conditions cause overgrowth of tissues. The purpose of this study was to determine the efficacy and safety of liposuction techniques for pediatric overgrowth diseases. Patients treated between 2007 and 2015 who had follow-up were reviewed. Seventeen patients were included; the median age was 12.7 years. The causes of overgrowth included infiltrating lipomatosis (n = 7), capillary malformation (n = 6), hemihypertrophy (n = 1), infantile hemangioma (n = 1), lipedema (n = 1), and macrocephaly-capillary malformation (n = 1). Forty-seven percent had enlargement of an extremity, 41 percent had facial hypertrophy, and 12 percent had expansion of the trunk. All subjects had a reduction in the size of the overgrown area and improved quality of life. Suction-assisted tissue removal is an effective technique for reducing the volume of the subcutaneous compartment for patients with pediatric overgrowth diseases. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Somatic PIK3CA mutations are present in multiple tissues of facial infiltrating lipomatosis

BackgroundFacial infiltrating lipomatosis (FIL) is a congenital disorder that causes overgrowth of one side of the face. The purpose of this study was to determine whether PIK3CA mutations are present in tissues outside of the subcutaneous adipose.MethodsFIL tissues from three patients were dissected to enrich for cells from skin, subcutaneous tissue, orbicularis oris muscle, buccal fat, zygomatic bone, and mucosal neuroma. Endothelial cells within the affected tissue also were enriched using CD31 microbeads. Laser capture microdissection on formalin-fixed paraffin-embedded histologic sections was performed to collect specific cell types. DNA was extracted from each tissue and cell type, and measured for the abundance of mutant PIK3CA alleles using droplet digital PCR.ResultsWe detected mutant PIK3CA alleles in every tissue and cell type tested from each overgrown face; frequencies ranged from 1.5 to 53%. There were fewer mutant endothelial cells compared with nonendothelial cells, and the stromal cell compartment had the highest frequency of mutant cells in each tissue.ConclusionsPIK3CA mutations are not restricted to a single tissue or cell type in FIL. Overgrowth in this condition is likely due to the mutation arising in a cell that contributes to several different facial structures during embryogenesis.

Nodular Foot Myxedema Masquerading as Lymphedema.

Summary: Lymphedema results from abnormal development or injury to the lymphatic system. One-fourth of patients with lower extremity enlargement are erroneously labeled with “lymphedema.” We describe a patient with hypothyroidism who developed soft-tissue overgrowth of her foot. She was referred to our Lymphedema Program for management of “lymphedema” and overgrown toes. The patient’s lymphoscintigram showed normal lymphatic function in her extremities, and she was diagnosed with myxedema by histopathology. Nodular localized myxedema should be included in the differential diagnosis of lymphedema.

Facial wound closure in children using a 7-0 absorbable suture dressing.

BackgroundManagement of pediatric facial wounds is more challenging compared to adults. Suture removal is difficult, and children are less likely to protect the suture line postoperatively. The purpose of this study was to determine the efficacy of a facial wound closure regimen designed to ensure the best possible outcome in the pediatric population. MethodsChildren 12 years or younger who had a skin lesion resected from the face between 2007 and 2013 were investigated. Patients who had their wound closed using 7-0 absorbable suture, glue, and tape were studied. Predictive variables included patient age, indication for the procedure, size of the excised lesion, and location of the repair. Outcome measures were infection, wound dehiscence, and scar appearance. ResultsTwo-hundred sixty-one children were included (151 girls, 110 boys). The mean (SD) age was 4.0 years (3.3 y). Types of lesions that were excised were nevus (24.9%), cyst (22.2%), vascular anomaly (19.5%), pilomatrixoma (13.8%), accessory tragus (11.9%), scar (4.6%), or other (3.1%). The mean (SD) area of the resected specimen was 2.2 cm2 (3.9 cm2). The complication rate was 0.8% (infection, n = 1; dehiscence, n = 1). Four patients had an unfavorable appearing scar that widened (1.5%). DiscussionA facial wound closure regimen using small absorbable sutures, glue, and tape optimizes outcomes in the pediatric population. Suture removal is not required, complications are rare, and scar appearance is excellent.