Expanding the clinical phenotype of FGFR1 internal tandem duplication.

Closed spinal dysraphism (SD) is a type of neural tube defect originating during early embryonic development whereby the neural tissue of the spinal defect remains covered by skin, often coinciding with markers of cutaneous stigmata. It is hypothesized that these events are caused by multifactorial processes, including genetic and environmental causes. We present an infant with a unique congenital midline lesion associated with a closed SD. Through comprehensive molecular profiling of the intraspinal lesion and contiguous skin lesion, an internal tandem duplication (ITD) of the kinase domain of the fibroblast growth factor receptor 1 (FGFR1) gene was found. This ITD variant is somatic mosaic in nature as supported by a diminished variant allele frequency in the lesional tissue and by its absence in peripheral blood. FGFR1 ITD results in constitutive activation of the receptor tyrosine kinase to promote cell growth, differentiation, and survival through RAS/MAPK signaling. Identification of FGFR1 ITD outside of central nervous system tumors is exceedingly rare, and this report broadens the phenotypic spectrum of somatic mosaic FGFR1-related disease.

Syringocystadenocarcinoma Papilliferum in a Fifteen-Year-Old Girl: A Case Report and Review of the Literature.

Syringocystadenocarcinoma papilliferum (SCACP) is a rare malignant neoplasm arising from adnexal tissues and is the malignant complement to the benign neoplasm syringocystadenoma papilliferum (SCAP). SCACP lesions appear as raised nodules or inflammatory plaques and can be associated with SCAP or nevus sebaceous. There have been fewer than 100 described cases of this neoplasm in the literature, and all previously published cases have been described in adults, with the majority occurring in the elderly. We present a case of an adolescent female with a syringocystadenocarcinoma papilliferum arising from a large thigh mass harboring an in-frame alteration in MAP2K1 along with a brief review of the literature.

Early postnatal proliferation of rapidly involuting congenital hemangioma.

Congenital hemangiomas (CH) are benign vascular tumors characterized by being fully developed at birth and following a variable postnatal course. We present the case of a newborn with a CH who experienced proliferation before developing an ulceration followed by rapid involution. This case expands the clinical spectrum of CH, highlighting the variable course of this vascular tumor.

KRIT1-positive hyperkeratotic cutaneous capillary venous malformation.

Cerebral cavernous malformations (CCM) may present in sporadic or familial forms, with different cutaneous manifestations including deep blue nodules, capillary malformations, and hyperkeratotic cutaneous capillary venous malformations (HCCVM). We report the case of an infant with a KRIT1-positive HCCVM associated with familial CCM. Moreover, histopathology showed positive immunohistochemical stain with GLUT1, further expanding the differential diagnosis of GLUT1-positive vascular anomalies.

Clinical and radiological characteristics of patients with retroperitoneal infantile hemangiomas.

BACKGROUND: Infantile hemangiomas (IHs) are the most common tumors of infancy. The objective was to identify clinical and radiological patterns in patients with retroperitoneal IHs. METHODS: We reviewed patients from our Vascular Anomalies Center database with IHs and abdominal imaging presenting from 1999 to 2017 to identify retroperitoneal involvement. RESULTS: Eleven patients (10 females, one male) with retroperitoneal IHs were found. Cutaneous IHs were present in eight patients (five segmental (45%), three multifocal (27%)) and absent in 1 (9%). Segmental hemangiomas involved the face in 2/5 (40%) and lower body in 3/5 (60%). The most common symptoms were dyspnea (n = 4), hematochezia (n = 3), and/or ulceration (n = 2). Three patients were asymptomatic. Involved retroperitoneal organs included the duodenum (n = 4), pancreas (n = 3), and adrenal glands (n = 1). Non-retroperitoneal organ involvement included the liver (n = 5), non-duodenal small intestine (n = 4), and large intestine (n = 3). Perivascular retroperitoneal hemangiomas were seen in 6/11 patients (55%), most commonly surrounding the aorta (n = 5), iliac vessels (n = 2), and/or inferior vena cava (n = 2). Three of 11 patients (27%) had LUMBAR based on a segmental, sacral hemangioma with tethered cord or anorectal malformation. Follow-up information was available in 6/11 patients (55%): 5 symptomatically improved with treatment (propranolol, corticosteroids, and/or vincristine), while one succumbed from extensive hepatic involvement. CONCLUSION: Retroperitoneal IHs are rare and tend to involve organs or surround vessels. Associated cutaneous IHs, if present, lack anatomical predilection and may be segmental or multifocal.

Lymphaticovenous bypass of the thoracic duct for the treatment of chylous leak in central conducting lymphatic anomalies.

BACKGROUND: Central conducting lymphatic anomalies (CCLA) may cause chylous leaks and protein-losing enteropathy (PLE) owing to dysfunction of the central lymphatic channels. Most of the treatment strategies for these conditions are palliative and provide transient improvement. METHODS: We treated 14 patients with intractable chylous leak and/or PLE using a novel technique of lymphaticovenous bypass of the terminal portion of the thoracic duct. Chylous leaks occurred in multiple different anatomic sites. All patients had CCLA and failure of thoracic duct emptying demonstrated by preoperative intranodal lymphangiography. RESULTS: Five patients had complete resolution of symptoms, and two patients had partial improvement. There were no major complications. Of 5 patients with PLE, only one improved after lymphaticovenous bypass. Repeat traditional lymphangiography was performed in 4 patients who did not improve, demonstrating patency of the bypass in all cases with persistent sluggish drainage. One patient had repeat MR lymphangiography that did not show the thoracic duct well. CONCLUSIONS: Bypass of the terminal thoracic duct is a novel procedure that offers improvement and a chance of cure for some patients with devastating manifestations of CCLA who lack other effective therapeutic options. LEVEL OF EVIDENCE: IV.

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.

Endovascular Treatment of Congenital Arterioportal Fistulas.

PURPOSE: To characterize anatomy of congenital arterioportal fistulas (CAPF) and correlate this with technique and outcomes of transcatheter embolization (TCE). MATERIALS AND METHODS: Retrospective review was conducted of children with CAPF that underwent TCE in a 10-year period. Medical records, imaging and procedure details were reviewed. TCE was performed via transarterial (n = 5), portal (n = 5) or patent ductus venosus (n = 1) approach. Embolic agents used were coils (n = 10), Onyx (n = 1) and Amplatzer septal occluder (n = 1). RESULTS: A total of 7 patients were included (4 female). Median age at treatment was 4 months (2 month-3 year). Most common symptoms were GI bleeding (n = 4), anemia (n = 4) and ascites (n = 3). Hepatopetal flow was seen in all on pre-procedure sonography. On angiography, a simple lesion, with direct fistulous connections, from hepatic arterial (HA) branches to portal venous (PV) system was seen in 3. A complex lesion with multiple connections was identified in 4. In simple lesions, cessation of shunting was achieved in 1 procedure, with embolization of afferent vessels. In complex lesions, multiple procedures were required in 3 of 4 patients. All 4 with complex connections required embolization of the aneurysmal PV segment. There were no major complications. Two minor complications were noted: localized biliary leak in 1 and femoral pseudoaneurysm in 1. There was resolution of symptoms in 6. CONCLUSIONS: TCE is effective as primary treatment of CAPF. Patients with simple arteriovenous connections can be treated with embolization of afferent vessels, but children with multiple complex connections usually require embolization of the dilated PV segment.

Internal venous anomalies in patients with a genital venous malformation.

BACKGROUND: Cutaneous venous malformation (VM) can be associated with internal vascular anomalies. Our objective was to investigate the frequency of internal vascular anomalies in patients with an isolated genital venous malformation to assess the utility of screening for internal findings. METHODS: We retrospectively reviewed our Vascular Anomalies Center database for patients with a focal genital venous malformation presenting between 1999 and 2016. Abdominal and pelvic imaging reports were reviewed for internal vascular anomalies. Endoscopy reports were also reviewed when available. RESULTS: A focal genital venous malformation was found in 22 patients (14 female, 8 male). Ten (45%) had a venous malformation of at least one internal structure, most commonly the pelvic floor (n = 6), colon (n = 5), urethra (n = 4), and/or bladder (n = 3). Eight experienced hematuria, hematochezia, and/or rectorrhagia secondary to their internal venous malformation. In patients with internal venous malformations, the mean age of symptom presentation was 7.3 years (range 1-22 years). Two patients had malformed inferior mesenteric and portal veins visible using ultrasonography and magnetic resonance imaging. They required surgical intervention to prevent thrombosis and decrease urogenital and gastrointestinal bleeding. CONCLUSION: Nearly half of our patients with a focal genital venous malformation had internal venous anomalies. Physicians should suspect urogenital or gastrointestinal venous malformations in patients with a focal genital venous malformation, especially if they develop hematuria, hematochezia, or rectorrhagia. Significant mesenteric venous trunk anomalies can also occur. Because these require surgical intervention, early recognition is important. We recommend that all patients with a focal genital venous malformation undergo abdominal and pelvic ultrasound to evaluate for internal venous anomalies.

Misdiagnosis of plexiform neurofibroma as venous malformation in pediatric patients.

BACKGROUND: The aim of this study was to identify Magnetic Resonance Imaging (MRI) characteristics that reliably distinguish deep plexiform neurofibromas (PNFs) from venous malformations (VMs). METHODS: A database search was conducted for patients that were referred with a vascular anomaly but had a neurofibroma instead. Clinical and imaging features of patients with venous malformations as the most common referral diagnosis were compared to those with PNFs. The imaging features of deep PNFs recorded were: anatomical location, size, morphology, margins, signal intensity and post-contrast enhancement pattern. RESULTS: Ten patients with PNFs were identified. Five patients had adequate imaging. These five patients were included in our study. There were 3 female and 2 male patients ranging in age from 10 months to 21 years. Deep PNFs were located in the cervicofacial region (N.=3), lower extremity (N.=1) and back/flank region (N.=1). The most common clinical features of all these patients were palpable mass (N.=5) and pain (N.=4). The MRI features that distinguished VMs from deep PNFs were the serpiginous morphology, relatively intermediate T-2 signal intensity and peculiar enhancement pattern without fluid-fluid levels or phleboliths and nerve root involvement. The target sign can be regularly found in PNFs, but may be also present in VMs and other vascular lesions. CONCLUSIONS: Target signs, a typical sign of PNFs may be absent and can also be found in vascular anomalies, leading to confusion in diagnosis. PNFs can be reliably distinguished from VMs on MRI based on the above mentioned features.

LDL Receptor-Related Protein-1 (LRP1) Regulates Cholesterol Accumulation in Macrophages.

Within the circulation, cholesterol is transported by lipoprotein particles and is taken up by cells when these particles associate with cellular receptors. In macrophages, excessive lipoprotein particle uptake leads to foam cell formation, which is an early event in the development of atherosclerosis. Currently, mechanisms responsible for foam cell formation are incompletely understood. To date, several macrophage receptors have been identified that contribute to the uptake of modified forms of lipoproteins leading to foam cell formation, but the in vivo contribution of the LDL receptor-related protein 1 (LRP1) to this process is not known [corrected]. To investigate the role of LRP1 in cholesterol accumulation in macrophages, we generated mice with a selective deletion of LRP1 in macrophages on an LDL receptor (LDLR)-deficient background (macLRP1-/-). After feeding mice a high fat diet for 11 weeks, peritoneal macrophages isolated from Lrp+/+ mice contained significantly higher levels of total cholesterol than those from macLRP1-/- mice. Further analysis revealed that this was due to increased levels of cholesterol esters. Interestingly, macLRP1-/- mice displayed elevated plasma cholesterol and triglyceride levels resulting from accumulation of large, triglyceride-rich lipoprotein particles in the circulation. This increase did not result from an increase in hepatic VLDL biosynthesis, but rather results from a defect in catabolism of triglyceride-rich lipoprotein particles in macLRP1-/- mice. These studies reveal an important in vivo contribution of macrophage LRP1 to cholesterol homeostasis.

Percutaneous coil embolization of massive pelvic pseudoaneurysm in an infant.

Iatrogenic pseudoaneurysm formation is an uncommon but potentially serious complication of cardiac catheterization. This case report describes diagnosis and treatment of a large left external iliac artery pseudoaneurysm in a 3-month-old boy following cardiac catheterization and aortic balloon dilatation for aortic coarctation. A 4-cm pulsatile mass in the left hemipelvis was discovered on MRI performed 6 weeks later for possible tethered spinal cord. Sonography and angiography showed a large pseudoaneurysm of the left external iliac artery just distal to the iliac bifurcation with no flow in the external iliac artery distal to the pseudoaneurysm. Percutaneous US-guided thrombin injection was performed twice, with partial recanalization after each treatment. The residual portion of the pseudoaneurysm was then successfully embolized with percutaneous coils deployed under US and fluoroscopic guidance.

Macrophage LRP1 suppresses neo-intima formation during vascular remodeling by modulating the TGF-ß signaling pathway.

BACKGROUND: Vascular remodeling in response to alterations in blood flow has been shown to modulate the formation of neo-intima. This process results from a proliferative response of vascular smooth muscle cells and is influenced by macrophages, which potentiate the development of the intima. The LDL receptor-related protein 1 (LRP1) is a large endocytic and signaling receptor that recognizes a number of ligands including apoE-containing lipoproteins, proteases and protease-inhibitor complexes. Macrophage LRP1 is known to influence the development of atherosclerosis, but its role in vascular remodeling has not been investigated. METHODOLOGY/PRINCIPAL FINDINGS: To define the contribution of macrophage LRP1 to vascular remodeling, we generated macrophage specific LRP1-deficient mice (macLRP1-/-) on an LDL receptor (LDLr) knock-out background. Using a carotid ligation model, we detected a 2-fold increase in neointimal thickening and a 2-fold increase in the intima/media ratio in macLRP1-/- mice. Quantitative RT-PCR arrays of the remodeled vessel wall identified increases in mRNA levels of the TGF-ß2 gene as well as the Pdgfa gene in macLRP1-/- mice which could account for the alterations in vascular remodeling. Immunohistochemistry analysis revealed increased activation of the TGF-ß signaling pathway in macLRP1-/- mice. Further, we observed that LRP1 binds TGF-ß2 and macrophages lacking LRP1 accumulate twice as much TGF-ß2 in conditioned media. Finally, TNF-α modulation of the TGF-ß2 gene in macrophages is attenuated when LRP1 is expressed. Together, the data reveal that LRP1 modulates both the expression and protein levels of TGF-ß2 in macrophages. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate that macrophage LRP1 protects the vasculature by limiting remodeling events associated with flow. This appears to occur by the ability of macrophage LRP1 to reduce TGF-ß2 protein levels and to attenuate expression of the TGF-ß2 gene resulting in suppression of the TGF-ß signaling pathway.

LDL receptor-related protein 1: unique tissue-specific functions revealed by selective gene knockout studies.

The LDL receptor-related protein (originally called LRP, but now referred to as LRP1) is a large endocytic receptor that is widely expressed in several tissues. LRP1 is a member of the LDL receptor family that plays diverse roles in various biological processes including lipoprotein metabolism, degradation of proteases, activation of lysosomal enzymes, and cellular entry of bacterial toxins and viruses. Deletion of the LRP1 gene leads to lethality in mice, revealing a critical, but as of yet, undefined role in development. Tissue-specific gene deletion studies reveal an important contribution of LRP1 in the vasculature, central nervous system, macrophages, and adipocytes. Three important properties of LRP1 dictate its diverse role in physiology: 1) its ability to recognize more than 30 distinct ligands, 2) its ability to bind a large number of cytoplasmic adaptor proteins via determinants located on its cytoplasmic domain in a phosphorylation-specific manner, and 3) its ability to associate with and modulate the activity of other transmembrane receptors such as integrins and receptor tyrosine kinases.

Murine low-density lipoprotein receptor-related protein 1 (LRP) is required for phagocytosis of targets bearing LRP ligands but is not required for C1q-triggered enhancement of phagocytosis.

C1q and members of the defense collagen family are pattern recognition molecules that bind to pathogens and apoptotic cells and trigger a rapid enhancement of phagocytic activity. Candidate phagocytic cell receptors responsible for the enhancement of phagocytosis by defense collagens have been proposed but not yet discerned. Engagement of phagocyte surface-associated calreticulin in complex with the large endocytic receptor, low-density lipoprotein receptor-related protein 1 (LRP/CD91), by defense collagens has been suggested as one mechanism governing enhanced ingestion of C1q-coated apoptotic cells. To investigate this possibility, macrophages were derived from transgenic mice genetically deficient in LRP resulting from tissue-specific loxP/Cre recombination. LRP-deficient macrophages were impaired in their ability to ingest beads coated with an LRP ligand when compared with LRP-expressing macrophages, confirming for the first time that LRP participates in phagocytosis. When LRP-deficient and -expressing macrophages were plated on C1q-coated slides, they demonstrated equivalently enhanced phagocytosis of sheep RBC suboptimally opsonized with IgG or complement, compared with cells plated on control protein. In addition, LRP-deficient and -expressing macrophages ingested equivalent numbers of apoptotic Jurkat cells in the presence and absence of serum. Both LRP-deficient and -expressing macrophages ingested fewer apoptotic cells when incubated in the presence of C1q-deficient serum compared with normal mouse serum, and the addition of purified C1q reconstituted uptake to control serum levels. These studies demonstrate a direct contribution of LRP to phagocytosis and indicate that LRP is not required for the C1q-triggered enhancement of phagocytosis, suggesting that other, still undefined, receptor(s) exist to mediate this important innate immune function.