Immunohistochemical Expression of Lymphatic Endothelial Markers in Blue Rubber Bleb Nevus Syndrome.

INTRODUCTION: Blue rubber bleb nevus syndrome (BRBNS) is an uncommon vascular anomaly characterized by multifocal cutaneous, visceral, and other soft tissue or solid organ venous malformations. We observed that BRBNS lesions express immunohistochemical markers of lymphatic differentiation. METHODS: BRBNS histopathologic specimens assessed at our institution during the past 27 years were reviewed. Slides from 19 BRBNS lesions were selected from 14 patients (9 cutaneous, 9 gastrointestinal, and 1 hepatic). We recorded the involved anatomical compartments and presence/absence of thrombi or vascular smooth muscle. Immunohistochemical endothelial expression of PROX1 (nuclear) and D2-40 (membranous/cytoplasmic) was evaluated semi-quantitatively. RESULTS: Endothelial PROX1 immunopositivity was noted in all specimens; the majority (89.5%) demonstrated staining in more than 10% of cells. D2-40 immunopositivity was present in one-third (33%) of cutaneous lesions and only 1 gastrointestinal lesion. CONCLUSION: Endothelial cells in BRBNS almost always express 1 or more immunohistochemical markers of lymphatic differentiation.

Endothelial cell expression of mutant Map2k1 causes vascular malformations in mice.

Extracranial arteriovenous malformation (AVM) is a congenital vascular anomaly causing disfigurement, bleeding, ulceration, and pain. Most lesions are associated with somatic MAP2K1 activating mutations in endothelial cells (ECs). The purpose of this study was to determine if EC expression of mutant activated MAP2K1 is sufficient to produce vascular malformations in mice. We generated mice with a ROSA26 allele containing a lox-stop-lox gene trap (GT), Map2k1 cDNA with an activating p.K57N missense mutation, an internal ribosomal entry site, and green fluorescent protein cDNA (R26GT-Map2k1-GFP). We expressed mutant MAP2K1 and GFP in ECs of fetal and newborn mice using Tg-Cdh5Cre or Tg-Cdh5CreER alleles. Tg-Cdh5Cre+/-;R26GT-Map2k1-GFP/+ animals that express mutant MAP2K1 in ECs in utero developed diffuse vascular abnormalities and died by embryonic (E) day 16.5. Tg-Cdh5CreER+/-;R26GT-Map2k1-GFP/+ animals in which mutant MAP2K1 expression was induced in ECs by tamoxifen at postnatal (P) day 1 developed vascular malformations in the brain, ear, and intestines by P23. The lesions consisted of abnormal networks of blood vessels containing recombined and non-recombined ECs. In conclusion, expression of MAP2K1 p.K57N is sufficient to cause vascular malformations in mice. This model can be used to study the malformation process and for pre-clinical pharmacologic studies.

Kaposiform lymphangiomatosis: Diagnosis, pathogenesis, and treatment.

Kaposiform lymphangiomatosis (KLA) is a life-threatening rare disease that can cause substantial morbidity, mortality, and social burdens for patients and their families. Diagnosis often occurs long after initial symptoms, and there are few centers in the world with the expertise to diagnose and care for patients with the disease. KLA is a lymphatic anomaly and significant advancements have been made in understanding its pathogenesis and etiology since its first description in 2014. This review provides multidisciplinary, comprehensive, and state-of-the-art information on KLA patient presentation, diagnostic imaging, pathology, organ involvement, genetics, and pathogenesis. Finally, we describe current therapeutic approaches, important areas for research, and challenges faced by patients and their families. Further insights into the pathogenesis of KLA may advance our understanding of other vascular anomalies given that similar signaling pathways may be involved.

Congenital Disseminated Pyogenic Granuloma: Characterization of an Aggressive Multisystemic Disorder.

OBJECTIVE: To describe the clinical, radiologic, and histopathologic features of "congenital disseminated pyogenic granuloma" involving various organs with high morbidity related to cerebral hemorrhagic involvement. STUDY DESIGN: We searched the database of the Vascular Anomalies Center at Boston Children's Hospital from 1999 to 2019 for patients diagnosed as having multiple vascular lesions, visceral vascular tumors, congenital hemangiomatosis, multiple pyogenic granulomas, or multiple vascular lesions without a definite diagnosis. A retrospective review of the medical records, photographs, histopathologic, and imaging studies was performed. Only patients with imaging studies and histopathologic diagnosis of pyogenic granuloma were included. RESULTS: Eight children (5 male, 3 female) had congenital multifocal cutaneous vascular tumors. Lesions also were found in the brain (n = 7), liver (n = 4), spleen (n = 3), muscles (n = 4), bone (n = 3), retroperitoneum (n = 3), and intestine/mesentery (n = 2). Less commonly affected were the spinal cord, lungs, kidneys, pancreas, and adrenal gland (n = 1 each). The mean follow-up period was 21.8 months. The cerebral and visceral lesions were hemorrhagic with severe neurologic sequelae. The histopathologic diagnosis was pyogenic granuloma with prominent areas of hemorrhage and necrosis. The endothelial cells had enlarged nuclei, pale cytoplasm and were immunopositive for CD31 and negative for D2-40 and glucose transporter 1. CONCLUSIONS: Congenital disseminated pyogenic granuloma is a distinct multisystemic aggressive disorder that primarily affects the skin, brain, visceral organs, and musculoskeletal system. Differentiation of this entity from other multiple cutaneous vascular lesions is critical because of possible cerebral hemorrhagic involvement.

High serum serotonin in sudden infant death syndrome.

Sudden infant death syndrome (SIDS), the leading cause of postneonatal infant mortality, likely comprises heterogeneous disorders with the common phenotype of sudden death without explanation upon postmortem investigation. Previously, we reported that ∼40% of SIDS deaths are associated with abnormalities in serotonin (5-hydroxytryptamine, 5-HT) in regions of the brainstem critical in homeostatic regulation. Here we tested the hypothesis that SIDS is associated with an alteration in serum 5-HT levels. Serum 5-HT, adjusted for postconceptional age, was significantly elevated (95%) in SIDS infants (n = 61) compared with autopsied controls (n = 15) [SIDS, 177.2 ± 15.1 (mean ± SE) ng/mL versus controls, 91.1 ± 30.6 ng/mL] (P = 0.014), as determined by ELISA. This increase was validated using high-performance liquid chromatography. Thirty-one percent (19/61) of SIDS cases had 5-HT levels greater than 2 SDs above the mean of the controls, thus defining a subset of SIDS cases with elevated 5-HT. There was no association between genotypes of the serotonin transporter promoter region polymorphism and serum 5-HT level. This study demonstrates that SIDS is associated with peripheral abnormalities in the 5-HT pathway. High serum 5-HT may serve as a potential forensic biomarker in autopsied infants with SIDS with serotonergic defects.

Fibroadipose Vascular Anomaly in the Upper Extremity: A Distinct Entity With Characteristic Clinical, Radiological, and Histopathological Findings.

PURPOSE: Fibroadipose vascular anomaly (FAVA) is an intramuscular vascular malformation that has been recently described as a distinct clinical entity. The clinical, radiological, and histopathological characteristics of FAVA in the upper extremity are reviewed. METHODS: This was a retrospective case series of upper-extremity FAVA lesions. RESULTS: We reviewed 19 patients with FAVA of the upper limb. Pain, stiffness, swelling, and flexion contractures were the most common presentations. Except for one lesion confined to the hand, all lesions either presented with or developed a contracture within 10 years. Ten patients underwent surgical debulking. Six required tendon transfer reconstruction and 3 necessitated a free functional muscle transfer. CONCLUSIONS: Fibroadipose vascular anomaly in the upper extremity requires an accurate diagnosis and may benefit from early referral to a multidisciplinary vascular anomaly center with experienced hand surgeons. Compression garments, propranolol, and sclerotherapy seem to be ineffective. Surgical resection focused on symptomatic regions with appropriate reconstruction may have benefit in salvage of limbs with compromised function. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Surgical Management of Fibroadipose Vascular Anomaly of the Lower Extremities.

BACKGROUND: Fibroadipose vascular anomaly (FAVA) is a recently-defined vascular malformation often involving the extremities and presenting in childhood. Patients may present to orthopaedic surgeons with pain, swelling, joint contractures, and leg length discrepancy. There is no established therapy or treatment paradigm. We report on outcomes following surgical excision for patients with this condition. METHODS: Between 2007 and 2016, all 35 patients that underwent excision of lower-extremity FAVA were retrospectively reviewed using a combination of medical records, radiologic findings, and telemedicine reviews. RESULTS: Mean age at initial presentation was 12.3±6.8 years. Mean follow-up from time of definitive diagnosis at our institution was 66 months (range: 12 to 161 mo). Mean follow-up after surgery was 35 months (range: 6 to 138 mo). Females were affected more than males (71% vs. 29%). The most common location of FAVA was in the calf (49%), followed by the thigh (40%). The most commonly involved muscle was gastrocnemius (29%), followed by the quadriceps (26%). At latest follow-up after surgery, there was an improvement in the proportion of patients with pain at rest (63% vs. 29%), pain with activity (100% vs. 60%), as well as analgesia use (94% vs. 37%). Fourteen patients (40%) had symptomatic residual disease or recurrence of FAVA requiring further treatment. Six patients (17%) required further surgery and 6 (17%) required further interventional radiologic procedures. Three patients (9%) required eventual amputation for intractable pain and loss of function. Lesions with direct nerve involvement were associated with persistent neuropathic symptoms at latest follow-up (P=0.002) as well as symptomatic residual disease and/or recurrence requiring further treatment (P=0.01). Seventeen patients (49%) had 19 preoperative joint contractures. Eighteen of the 19 contractures (95%) had sustained improvement at latest follow-up. CONCLUSIONS: In carefully selected patients, surgical excision of FAVA results in improvement of symptoms. However, symptomatic residual disease and/or recurrence are not uncommon. Direct nerve involvement is associated with a worse outcome. LEVEL OF EVIDENCE: Level IV-case series.

Intramuscular fast-flow vascular anomaly contains somatic MAP2K1 and KRAS mutations.

BACKGROUND: The term "intramuscular hemangioma capillary type" (IHCT) refers to a fast-flow vascular lesion that is classified as a tumor, although its phenotype overlaps with arteriovenous malformation (AVM). The purpose of this study was to identify somatic mutations in IHCT. METHODS: Affected tissue specimens were obtained during a clinically indicated procedure. The diagnosis of IHCT was based on history, physical examination, imaging and histopathology. Because somatic mutations in cancer-associated genes can cause vascular malformations, we sequenced exons from 446 cancer-related genes in DNA from 7 IHCT specimens. We then performed mutation-specific droplet digital PCR (ddPCR) to independently test for the presence of a somatic mutation found by sequencing and to screen one additional IHCT sample. RESULTS: We detected somatic mutations in 6 of 8 IHCT specimens. Four specimens had a mutation in MAP2K1 (p.Q58_E62del, p.P105_I107delinsL, p.Q56P) and 2 specimens had mutations in KRAS (p.K5E and p.G12D, p.G12D and p.Q22R). Mutant allele frequencies detected by sequencing and confirmed by ddPCR ranged from 2 to 15%. CONCLUSIONS: IHCT lesions are phenotypically similar to AVMs and contain the same somatic MAP2K1 or KRAS mutations, suggesting that IHCT is on the AVM spectrum. We propose calling this lesion "intramuscular fast-flow vascular anomaly."

Somatic Activating Mutations in GNAQ and GNA11 Are Associated with Congenital Hemangioma.

Congenital hemangioma is a rare vascular tumor that forms in utero. Postnatally, the tumor either involutes quickly (i.e., rapidly involuting congenital hemangioma [RICH]) or partially regresses and stabilizes (i.e., non-involuting congenital hemangioma [NICH]). We hypothesized that congenital hemangiomas arise due to somatic mutation and performed massively parallel mRNA sequencing on affected tissue from eight participants. We identified mutually exclusive, mosaic missense mutations that alter glutamine at amino acid 209 (Glu209) in GNAQ or GNA11 in all tested samples, at variant allele frequencies (VAF) ranging from 3% to 33%. We verified the presence of the mutations in genomic DNA using a combination of molecular inversion probe sequencing (MIP-seq) and digital droplet PCR (ddPCR). The Glu209 GNAQ and GNA11 missense variants we identified are common in uveal melanoma and have been shown to constitutively activate MAPK and/or YAP signaling. When we screened additional archival formalin-fixed paraffin-embedded (FFPE) congenital cutaneous and hepatic hemangiomas, 4/8 had GNAQ or GNA11 Glu209 variants. The same GNAQ or GNA11 mutation is found in both NICH and RICH, so other factors must account for these tumors' different postnatal behaviors.

A somatic activating NRAS variant associated with kaposiform lymphangiomatosis.

PURPOSE: Kaposiform lymphangiomatosis (KLA) is a rare, frequently aggressive, systemic disorder of the lymphatic vasculature, occurring primarily in children. Even with multimodal treatments, KLA has a poor prognosis and high mortality rate secondary to coagulopathy, effusions, and systemic involvement. We hypothesized that, as has recently been found for other vascular anomalies, KLA may be caused by somatic mosaic variants affecting vascular development. METHODS: We performed exome sequencing of tumor samples from five individuals with KLA, along with samples from uninvolved control tissue in three of the five. We used digital polymerase chain reaction (dPCR) to validate the exome findings and to screen KLA samples from six other individuals. RESULTS: We identified a somatic activating NRAS variant (c.182 A>G, p.Q61R) in lesional tissue from 10/11 individuals, at levels ranging from 1% to 28%, that was absent from the tested control tissues. CONCLUSION: The activating NRAS p.Q61R variant is a known "hotspot" variant, frequently identified in several types of human cancer, especially melanoma. KLA, therefore, joins a growing group of vascular malformations and tumors caused by somatic activating variants in the RAS/PI3K/mTOR signaling pathways. This discovery will expand treatment options for these high-risk patients as there is potential for use of targeted RAS pathway inhibitors.

A somatic MAP3K3 mutation is associated with verrucous venous malformation.

Verrucous venous malformation (VVM), also called "verrucous hemangioma," is a non-hereditary, congenital, vascular anomaly comprised of aberrant clusters of malformed dermal venule-like channels underlying hyperkeratotic skin. We tested the hypothesis that VVM lesions arise as a consequence of a somatic mutation. We performed whole-exome sequencing (WES) on VVM tissue from six unrelated individuals and looked for somatic mutations affecting the same gene in specimens from multiple persons. We observed mosaicism for a missense mutation (NM_002401.3, c.1323C>G; NP_002392, p.Iso441Met) in mitogen-activated protein kinase kinase kinase 3 (MAP3K3) in three of six individuals. We confirmed the presence of this mutation via droplet digital PCR (ddPCR) in the three subjects and found the mutation in three additional specimens from another four participants. Mutant allele frequencies ranged from 6% to 19% in affected tissue. We did not observe this mutant allele in unaffected tissue or in affected tissue from individuals with other types of vascular anomalies. Studies using global and conditional Map3k3 knockout mice have previously implicated MAP3K3 in vascular development. MAP3K3 dysfunction probably causes VVM in humans.

Recurrent EML4-NTRK3 fusions in infantile fibrosarcoma and congenital mesoblastic nephroma suggest a revised testing strategy.

Infantile fibrosarcoma and congenital mesoblastic nephroma are tumors of infancy traditionally associated with the ETV6-NTRK3 gene fusion. However, a number of case reports have identified variant fusions in these tumors. In order to assess the frequency of variant NTRK3 fusions, and in particular whether the recently identified EML4-NTRK3 fusion is recurrent, 63 archival cases of infantile fibrosarcoma, congenital mesoblastic nephroma, mammary analog secretory carcinoma and secretory breast carcinoma (tumor types that are known to carry recurrent ETV6-NTRK3 fusions) were tested with NTRK3 break-apart FISH, EML4-NTRK3 dual fusion FISH, and targeted RNA sequencing. The EML4-NTRK3 fusion was identified in two cases of infantile fibrosarcoma (one of which was previously described), and in one case of congenital mesoblastic nephroma, demonstrating that the EML4-NTRK3 fusion is a recurrent genetic event in these related tumors. The growing spectrum of gene fusions associated with infantile fibrosarcoma and congenital mesoblastic nephroma along with the recent availability of targeted therapies directed toward inhibition of NTRK signaling argue for alternate testing strategies beyond ETV6 break-apart FISH. The use of either NTRK3 FISH or next-generation sequencing will expand the number of cases in which an oncogenic fusion is identified and facilitate optimal diagnosis and treatment for patients.

Fibrous hamartoma of infancy: a clinicopathologic study of 145 cases, including 2 with sarcomatous features.

Fibrous hamartoma of infancy is a rare soft tissue lesion of infants and young children with characteristic triphasic morphology, which typically occurs in the axilla and less commonly in other locations. We reviewed 145 cases of fibrous hamartoma of infancy from our consultation archives. Cases occurred in 106 males and 39 females (mean age-15 months; range-birth to 14 years), and involved both typical sites (eg, axilla/back/upper arm) (n=69) and unusual locations (n=76). Six were congenital. The tumors presented as subcutaneous masses and ranged from 0.4 to 17 cm (mean 3 cm). All displayed triphasic morphology, but varied widely in the relative percentages of fat, fibroblastic fascicles, and primitive mesenchyme. Hyalinized zones with cracking artifact, mimicking giant cell fibroblastoma, were present in a 44 (30%) of cases; however FISH for PDGFB gene rearrangement was negative in five tested cases. In addition to classical fibrous hamartoma of infancy, two lesions contained large sarcomatous-appearing foci with high cellularity, high nuclear grade, and brisk mitotic activity. One occurred in a 10-month-old female as a new mass in a congenital fibrous hamartoma of infancy; the other occurred as a leg mass in a 6-year-old male. ETV6 gene rearrangement was negative in the tumor from the 10-month-old female. Genomic microarray (OncoScan) showed normal molecular karyotype in eight tested cases, whereas the two tumors with sarcomatous features showed a hyperdiploid/near tetraploid molecular karyotype with copy neutral loss of heterozygosity of chromosomes 1p and 11p, and loss of 10p, chromosome 14, and a large portion of chromosome 22q (22q11.23q13.33), respectively. Follow-up (52 patients; range: 1-208 months, median: 8 months) showed only two local recurrences and no metastases. Extensive local disease in the 10-month-old female with sarcomatous-appearing fibrous hamartoma of infancy necessitated forequarter amputation. In summary, our study confirms the classic clinicopathologic features, including the triphasic morphologic appearance of most cases. In contrast to earlier studies, our series illustrates a broader histologic spectrum than previously appreciated, including its close resemblance to giant cell fibroblastoma in one quarter of cases and the rare presence of 'sarcomatous' areas, the latter providing evidence that these are complex neoplasms rather than hamartomas.

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.

Imaging features of kaposiform lymphangiomatosis.

BACKGROUND: Kaposiform lymphangiomatosis is a rare, aggressive lymphatic disorder. The imaging and presenting features of kaposiform lymphangiomatosis can overlap with those of central conducting lymphatic anomaly and generalized lymphatic anomaly. OBJECTIVE: To analyze the imaging findings of kaposiform lymphangiomatosis disorder and highlight features most suggestive of this diagnosis. MATERIALS AND METHODS: We retrospectively identified and characterized 20 children and young adults with histopathological diagnosis of kaposiform lymphangiomatosis and radiologic imaging referred to the vascular anomalies center between 1995 and 2015. RESULTS: The median age at onset was 6.5 years (range 3 months to 27 years). The most common presenting features were respiratory compromise (dyspnea, cough, chest pain; 55.5%), swelling/mass (25%), bleeding (15%) and fracture (5%). The thoracic cavity was involved in all patients; all patients had mediastinal involvement followed by lung parenchymal disease (90%) and pleural (85%) and pericardial (50%) effusions. The most common extra-thoracic sites of disease were the retroperitoneum (80%), bone (60%), abdominal viscera (55%) and muscles (45%). There was characteristic enhancing and infiltrative soft-tissue thickening in the mediastinum and retroperitoneum extending along the lymphatic distribution. CONCLUSION: Kaposiform lymphangiomatosis has overlapping imaging features with central conducting lymphatic anomaly and generalized lymphatic anomaly. Presence of mediastinal or retroperitoneal enhancing and infiltrative soft-tissue disease along the lymphatic distribution, hemorrhagic effusions and moderate thrombocytopenia (50-100,000/µl) should favor diagnosis of kaposiform lymphangiomatosis.

Somatic mosaic activating mutations in PIK3CA cause CLOVES syndrome.

Congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies (CLOVES) is a sporadically occurring, nonhereditary disorder characterized by asymmetric somatic hypertrophy and anomalies in multiple organs. We hypothesized that CLOVES syndrome would be caused by a somatic mutation arising during early embryonic development. Therefore, we employed massively parallel sequencing to search for somatic mosaic mutations in fresh, frozen, or fixed archival tissue from six affected individuals. We identified mutations in PIK3CA in all six individuals, and mutant allele frequencies ranged from 3% to 30% in affected tissue from multiple embryonic lineages. Interestingly, these same mutations have been identified in cancer cells, in which they increase phosphoinositide-3-kinase activity. We conclude that CLOVES is caused by postzygotic activating mutations in PIK3CA. The application of similar sequencing strategies will probably identify additional genetic causes for sporadically occurring, nonheritable malformations.

Lymphatic and other vascular malformative/overgrowth disorders are caused by somatic mutations in PIK3CA.

OBJECTIVES: To test the hypothesis that somatic phosphatidylinositol-4,5-bisphospate 3-kinase, catalytic subunit alpha (PIK3CA) mutations would be found in patients with more common disorders including isolated lymphatic malformation (LM) and Klippel-Trenaunay syndrome (KTS). STUDY DESIGN: We used next generation sequencing, droplet digital polymerase chain reaction, and single molecule molecular inversion probes to search for somatic PIK3CA mutations in affected tissue from patients seen at Boston Children's Hospital who had an isolated LM (n = 17), KTS (n = 21), fibro-adipose vascular anomaly (n = 8), or congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies syndrome (n = 33), the disorder for which we first identified somatic PIK3CA mutations. We also screened 5 of the more common PIK3CA mutations in a second cohort of patients with LM (n = 31) from Seattle Children's Hospital. RESULTS: Most individuals from Boston Children's Hospital who had isolated LM (16/17) or LM as part of a syndrome, such as KTS (19/21), fibro-adipose vascular anomaly (5/8), and congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies syndrome (31/33) were somatic mosaic for PIK3CA mutations, with 5 specific PIK3CA mutations accounting for ∼ 80% of cases. Seventy-four percent of patients with LM from Seattle Children's Hospital also were somatic mosaic for 1 of 5 specific PIK3CA mutations. Many affected tissue specimens from both cohorts contained fewer than 10% mutant cells. CONCLUSIONS: Somatic PIK3CA mutations are the most common cause of isolated LMs and disorders in which LM is a component feature. Five PIK3CA mutations account for most cases. The search for causal mutations requires sampling of affected tissues and techniques that are capable of detecting low-level somatic mosaicism because the abundance of mutant cells in a malformed tissue can be low.

Impact of Screening for Hepatic Hemangiomas in Patients with Multiple Cutaneous Infantile Hemangiomas.

OBJECTIVES: Hepatic hemangiomas are often found in association with multiple cutaneous infantile hemangiomas. Screening abdominal ultrasonography has been recommended for patients with five or more cutaneous lesions. We sought to determine whether hemangiomas found through screening had improved clinical outcomes. METHODS: Patients entered into our hepatic hemangioma registry between 1995 and 2012 were reviewed. RESULTS: Seventy-two patients with multiple cutaneous and hepatic hemangiomas were identified; 43 (60%) were detected through screening. The median age at diagnosis was 41 days for screened patients and 53 days for those not screened. Screening detected 40 (93%) multifocal and 3 (7%) diffuse hemangiomas, compared to 18 (62%) and 11 (38%), respectively, in the nonscreened group. Patients identified by screening had lower incidences of congestive heart failure and hypothyroidism and were less likely to receive treatment for their hemangiomas. The mortality rate in the children not screened was 28% (n = 8). None of the patients found by screening died (p < 0.001). Multivariate analysis of treated patients demonstrated that screening was a significant predictor of reduced mortality (p = 0.04). CONCLUSION: Hepatic hemangiomas found through screening ultrasonography are less likely to develop serious clinical sequelae. Although the reasons for this may include detection of hemangiomas that are less likely to progress to symptomatic disease, it appears that it also allows for earlier intervention for more concerning (e.g. diffuse) subtypes. Screening may allow for closer surveillance and earlier treatment before life-threatening progression in a subset of infants with liver hemangiomas, preventing complications and reducing mortality.

R132C IDH1 mutations are found in spindle cell hemangiomas and not in other vascular tumors or malformations.

Spindle cell hemangioma (SCH) is a rare, benign vascular tumor of the dermis and subcutis. The lesions can be multifocal and are overrepresented in Maffucci syndrome, in which patients also have multiple enchondromas. Somatic mosaic R132C IDH1 hotspot mutations were recently identified in Maffucci syndrome. We evaluated the presence of mutations in solitary and multiple SCHs in patients without multiple enchondromas and tested a range of other vascular lesions that enter into the differential diagnosis. The R132C IDH1 mutation was identified by hydrolysis probes assay and confirmed by Sanger sequencing in 18 of 28 (64%) SCHs; of the 10 negative cases, 2 harbored a mutation in IDH2 (R172T and R172M) by Sanger sequencing. None of 154 other vascular malformations and tumors harbored an IDH1 R132C mutation, and R132H IDH1 mutations were absent in all 182 cases. All 16 SCHs examined by immunohistochemistry were negative for expression of HIF-1α. In conclusion, 20 of 28 (71%) SCHs harbored mutations in exon 4 of IDH1 or IDH2. Given that mutations were absent in 154 other vascular lesions, the mutation seems to be highly specific for SCH. The mutation does not induce expression of HIF-1α in SCH, and therefore the exact mechanism by which mutations in IDH1 or IDH2 lead to vascular tumorigenesis remains to be established.