Microcystic lymphatic malformations in Turner syndrome are due to somatic mosaicism of PIK3CA.

Turner syndrome (45,X) is caused by a complete or partial absence of a single X chromosome. Vascular malformations occur due to abnormal development of blood and/or lymphatic vessels. They arise from either somatic or germline pathogenic variants in the genes regulating growth and apoptosis of vascular channels. Aortic abnormalities are a common, known vascular anomaly of Turner syndrome. However, previous studies have described other vascular malformations as a rare feature of Turner syndrome and suggested that vascular abnormalities in individuals with Turner syndrome may be more generalized. In this study, we describe two individuals with co-occurrence of Turner syndrome and vascular malformations with a lymphatic component. In these individuals, genetic testing of the lesional tissue revealed a somatic pathogenic variant in PIK3CA-a known and common cause of lymphatic malformations. Based on this finding, we conclude that the vascular malformations presented here and likely those previously in the literature are not a rare part of the clinical spectrum of Turner syndrome, but rather a separate clinical entity that may or may not co-occur in individuals with Turner syndrome.

The discriminative role of PROX-1 immunohistochemistry between venous malformation and lymphatic malformation of the deep type with no visible diagnostic surface skin lesion.

BACKGROUND: Venous malformations (VMs) are distinguished from lymphatic malformations (LMs) when specific diagnostic skin lesions are present. In the deep type, this is difficult by clinico-radiologic evaluation alone. We aimed to investigate the usefulness of lymphatic vessel endothelial cell (LEC) markers for the differential diagnosis of the deep VMs and LMs. METHODS: A retrospective study was conducted based on the medical records of patients with VMs and LMs who underwent biopsy with both D2-40 and PROX-1 immunohistochemistry. We compared the initial clinico-radiological diagnosis with the final pathological diagnosis and identified which ones showed a difference. RESULTS: From 261 patients who had VMs and LMs, 111 remained after the exclusion of those who showed definite surface diagnostic features. After pathological diagnosis with the expressions of D2-40 and PROX-1, 38 of 111 (34.2%) patients' final diagnoses were changed. Among these 38 cases, diagnosis was not changed by D2-40 positivity alone, but changed by PROX-1 positivity alone (52.6%) or by both (47.4%). The diagnostic changes were more frequent in the deep category (43.7%) than in the superficial category. CONCLUSIONS: Identifying the expression of D2-40, and especially PROX-1, in the differential diagnosis of VMs and LMs may provide important treatment guidelines and understanding their natural course.

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.

Mesenteric and omental lymphatic malformations in children: seven-year surgical experience from two centers in China.

PURPOSE: To compare the clinical characteristics, surgical management and prognosis of mesenteric lymphatic malformations (ML) and omental lymphatic malformations (OL) in children. METHODS: This retrospective study included 148 ML patients and 53 OL patients who underwent surgical treatment at two centers between January 2016 and December 2022. Details about the patients' clinical characteristics, cyst characteristics, preoperative complications, surgical methods, and prognosis were retrieved and compared. RESULTS: No significant differences in sex ratio, prenatal diagnosis, or age of diagnosis were noted between ML and OL patients. Vomiting was more common in ML patients than in OL patients (46.6% vs. 22.6%, P = 0.002), but OL patients were more likely to be misdiagnosed (35.8% vs. 18.9%, P = 0.012). The size of the cysts in OL patients was significantly larger than that in ML patients (14.0 [4.0-30.0] vs. 10.0 [2.0-50.0] cm, P<0.001), and cysts with turbid fluid were more common in OL patients (38.0% vs. 20.6%, P<0.001). More OL patients than ML patients had preoperative hemorrhage or infection of cysts (41.5% vs. 31.8%, P<0.016). Cyst excision was performed in 137 (92.6%) ML patients and 51 (96.2%) OL patients, and the incidence of postoperative complications was lower (12.6% vs. 4.2%, P = 0.165) among OL patients. The main postoperative complications included adhesive ileus and recurrence of cysts. Additionally, more OL patients than ML patients were treated with laparoscopic surgery (69.8% vs. 39.2%, P<0.001). CONCLUSIONS: There were differences in clinical characteristics, cyst characteristics and preoperative complications between ML and OL patients. Cyst excision was the most common surgical method that was used to treat both ML and OL patients, and laparoscopic surgery could be a feasible surgical approach for treating OL patients with a good prognosis. TRIAL REGISTRATION: Retrospectively registered.

Pediatric mediastinal lymphatic malformation: misdiagnosis analysis and literature review.

OBJECTIVES: Mediastinal cystic lymphatic malformation (MCLM) in children is prone to misdiagnosis as cystic teratoma. We compared the clinical and radiologic features between the two diseases and performed a cross-comparison with previous research on adult cases. This study aims to identify characteristic pediatric manifestations to improve diagnostic accuracy. METHODS: A retrospective study of clinical and radiologic data was conducted on 12 MCLM and 20 cases of cystic teratomas confirmed by pathology or intervention biopsy. Clinical characters and radiology features (mass location and morphology, density, component, secondary complication) were recorded and compared. We reviewed clinical studies on MCLM published in the past decades, analyzing radiological differences and comparing pediatric MCLM cases at our hospital with those in the literature. RESULTS: Group comparison in pediatrics between MCLM and cystic teratomas: There were significant age differences (p = 0.036), shape (p = 0.003), CT difference value (p < 0.001), CT difference ratio (p < 0.001), calcification (p < 0.001), fat (p < 0.001), and typing (p < 0.001) between the two diseases. An analysis of literature data on MCLM cases involved 16 studies. CONCLUSION: The absence of internal fat or irregular morphology, along with a minimal CT difference value, may suggest the diagnosis of MCLM. In pediatric cases, anterior mediastinal diseases tend to extend toward the neck, and the presence of the thymus can complicate the component analysis, thereby increasing the risk of misdiagnosis. Clinical diagnosis and differential diagnosis of pediatric MCLM rely heavily on imaging evaluation.

Cerebrospinal fluid-lymphatic fistula in a child with generalized lymphatic anomaly treated with targeted blood patch - a rare case report and review of the literature.

Spontaneous intracranial hypotension may result in debilitating postural headaches and severe neurological symptoms due to secondary cerebellar sagging. The most common cause is the cerebrospinal fluid (CSF) leak within the spinal canal. Although previously reported in only a few cases, also paraspinal lymphatic malformations causing vertebral bone destruction may occasionally result in CSF leak to these pathological formations. Here, we present a case of a 9-year-old girl with generalized lymphatic anomaly (GLA) presenting with severe postural headache. Radiological imaging revealed a typical feature of cerebellar sagging. Myelography localized the CSF leakage into vertebral bodies of C7 and Th1, which both were partly involved in pathological paravertebral masses of known lymphatic anomaly, and from there along the right C8 nerve root sleeve into the anomaly. As the C8-nerve root could not be ligated due to the risk of significant neurological injury, we attempted image-guided targeted percutaneous epidural placement of a blood patch directly into the foramen at the affected level. The procedure resulted in obliteration of the fistula and regression of cerebellar sagging, with significant relief of symptoms. Although it is an extremely rare coincidence, patients with paraspinal lymphatic malformations may develop intraspinal CSF leak into these pathological formations. The present case report suggests that besides a direct surgical obliteration of the fistula and sacrificing the nerve root, a targeted percutaneous epidural blood patch may be a possible alternative in the case of a functionally important nerve root.

Fetal Cystic Lymphatic Malformations: Systematic Review on Pregnancy and Neonatal Outcomes.

OBJECTIVE: Evaluate pregnancy and neonatal outcomes with fetal cystic lymphatic malformations (LMs), excluding those arising from the posterior neck, to facilitate patient counseling. METHOD: A systematic review was performed in accordance with PRISMA guidance. Case series and case reports published between 2000 and 2022 were included. RESULTS: Sixty-five studies (96 fetuses) met the inclusion criteria. The average gestational age at diagnosis was 25.5 weeks with the commonest location being the anterior neck (28%). All patients were diagnosed with LM using two-dimensional (2D) ultrasound. Prenatal progression in LM size, presence of intralesional bleeding, or fetal hydrops occurred in 70% (41/59), 9% (5/59), and 3% (2/59), respectively. Chromosomal and structural abnormalities were reported in 4% (2/52) and 2% (2/96), respectively. Overall livebirth rate was 94% (79/84); 12/96 resulted in termination and 5/84 in in utero demise. The average gestational age of delivery was 37.7 weeks. Exactly 19% (15/79) had a vaginal birth, of which shoulder dystocia occurred in one infant. Ex utero intrapartum treatment (EXIT) procedure was performed in 13% (10/79). Postnatal treatment commonly involved surgical excision 38% (30/79), sclerotherapy in 21.5% (17/79), or combination of both in 11.4% (9/79). Of those with reported follow-up, 4 died within 1 year, 1 developed heart failure at 2 years of life, and the remaining 44 had normal developmental outcomes. CONCLUSION: Fetal cystic LMs, excluding those in the posterior neck, are not commonly associated with chromosomal, or additional structural abnormalities. They usually increase in size before delivery with only a minority developing complications. The good developmental outcome was reported in all survivors.

Lymphatic System Development and Function.

PURPOSE OF REVIEW: This review delves into recent advancements in understanding generalized and organ-specific lymphatic development. It emphasizes the distinct characteristics and critical anomalies that can impair lymphatic function. By exploring developmental mechanisms, the review seeks to illuminate the profound impact of lymphatic malformations on overall health and disease progression. RECENT FINDINGS: The introduction of genome sequencing, single-cell transcriptomic analysis, and advanced imaging technologies has significantly enhanced our ability to identify and characterize developmental defects within the lymphatic system. As a result, a wide range of lymphatic anomalies have been uncovered, spanning from congenital abnormalities present at birth to conditions that can become life-threatening in adulthood. Additionally, recent research highlights the heterogeneity of lymphatics, revealing organ-specific developmental pathways, unique molecular markers, and specialized physiological functions specific to each organ. A deeper understanding of the unique characteristics of lymphatic cell populations in an organ-specific context is essential for guiding future research into lymphatic disease processes. An integrated approach to translational research could revolutionize personalized medicine, where treatments are precisely tailored to individual lymphatic profiles, enhancing effectiveness and minimizing side effects.

Surgery versus sclerotherapy versus combined therapy in head and neck lymphatic malformations in the pediatric population: systematic review and meta-analysis.

PURPOSE: To systematically review current literature on the treatment of lymphatic malformations (LMs) of the head and neck to guide treatment strategy. METHODS AND MATERIALS: A systematic review and meta-analysis of literature until 16 November 2021 was performed on treatments of LMs in the head and neck. RESULTS: Out of 9044 articles, 54 studies were eligible for inclusion with 26 studies providing detailed participant data. A total number of 1573 patients with a mean age of 21.22 months were analysed. Comparative meta-analysis did not reveal significant differences two proportions of volume reduction (≥ 50% and 100%) between sclerotherapy and surgical treatment. Regression demonstrated that positive predictors for volume reduction were surgery 17 (95% CI 0.26-34; p = 0.047) and treatment of macrocystic lesions 19 (95% CI 5.5-32; p = 0.006). Treatment of mixed lesions also demonstrated a trend towards achieving a greater volume reduction (p = 0.052). A higher de Serres stage of the lesion had a negative effect on the amount of volume reduction - 3.7 (95% CI - 7.0 to - 0.35; p = 0.030). CONCLUSION: This comprehensive meta-analysis demonstrated no significant difference in volume reduction between various treatment modalities at study level. However, individual patient data indicated that surgery and larger cyst types are associated with a significant higher percentage of volume reduction, whereas a higher de Serres stage negatively impacted the amount of volume reduction. These findings can be used for patient counseling and treatment planning based on cyst type and de Serres stage. However volume reduction constitutes just one objective within a more complex treatment spectrum.

Complications of pediatric macrocystic lymphatic malformations of the head and neck: a survival analysis of treated and untreated patients.

OBJECTIVE: To compare events of recurrent swelling between treated and untreated patients with macrocystic lymphatic malformations of the head and neck not involving the airway. The frequency and timing of emergency department (ED) visits related to the event were analysed to provide data on efficacy and ideal timing of treatment. METHODS: A 5-year retrospective review of a hospital database was conducted reviewing 35 patients (15 female, 20 male; mean age 3.9 years) with macrocystic lymphatic malformations of the head and neck not involving the airway. Patients treated with oral medications were excluded. A survival analysis was performed comparing the incidence of recurrent swelling of the malformation. A Cox regression analysis was conducted using age, gender, diameter of lymphatic malformation at presentation, and echogenicity on US as covariates. Fisher's test and mean comparisons were performed to correlate the populations baselines and the number and frequency of ED visits between the 2 groups. RESULTS: Thirteen patients underwent sclerotherapy soon after initial presentation and 22 elected for observation. The two baseline populations differed at presentation with the treatment group being younger (1.4 ± 2.4 vs. 5.4 ± 6.3 years, p = 0.03) and with larger lesions (5.7 ± 2.7 vs. 4.0 ± 1.7 cm p = 0.03). Mean follow-up time was 2.7 years. Survival analysis showed 1 or multiple recurrences affected 16 patients in the untreated group and 3 patients in the treated group. (p = 0.04). Age, gender, diameter of the lesion at presentation and increased echogenicity on US were not predictive factors of recurrence. Although the probability of visiting the ED at least once did not differ between the two groups (p = 0.42), patients from the non-treatment group were more likely to visit the ED more than once (p = 0.03). CONCLUSIONS: Sclerotherapy treatment may reduce the chance of recurrent swelling or an event after initial presentation to the ED.

Vascular Anomalies Care in the United States: A Cross-Sectional National Survey.

OBJECTIVE: To characterize the current distribution, composition, and practice patterns of multidisciplinary vascular anomalies (VAs) teams in the US. STUDY DESIGN: This is a cross-sectional survey of children's hospitals in the US offering VAs care. We approached 142 children's hospitals that provided care for VAs via email. The survey evaluated VA clinic location, medical staffing, research participation, and treatments offered. The survey was administered between October 2021 and July 2022. RESULTS: Participants from 95 eligible hospitals responded to the survey (response rate = 67%). Large areas of the Midwest and Northwest US had no available multidisciplinary VA teams or clinics. Most respondents worked at academic centers (89%), with 66% at a freestanding children's hospital, and 56% reported having a multidisciplinary clinic. Most common physician participants in clinic included hematology-oncology (91%), interventional radiology (87%), dermatology (85%), plastic surgery (81%), and otolaryngology (74%). Only 38% of programs included medical geneticists. Smaller hospitals had fewer medical and ancillary staff and offered fewer therapeutic options. Research was available at most larger institutions (69%) but less commonly at smaller hospitals (34%). CONCLUSIONS: Major portions of the US lack multidisciplinary VA care. Furthermore, VA programs vary in composition and geneticists are absent from the majority of programs. These findings should inform efforts to address disparate access and develop standards of care for multidisciplinary VA care in the US.

Perinatal presentations of non-immune hydrops fetalis due to recessive PIEZO1 disease: A challenging fetal diagnosis.

Hydrops fetalis is a rare disorder associated with significant perinatal complications and a high perinatal mortality of at least 50%. Nonimmune hydrops fetalis (NIHF) is more frequent and results from a wide variety of etiologies. One cause of NIHF is lymphatic malformation 6 (LMPHM6) due to biallelic loss-of-function (LoF) variants in PIEZO1. Most individuals are diagnosed postnatally and only few clinical data are available on fetal presentations. We report six novel biallelic predicted LoF variants in PIEZO1 identified by exome sequencing in six fetuses and one deceased neonate from four unrelated families affected with LMPHM6. During the pregnancy, most cases are revealed by isolated NIHF at second trimester of gestation. At post-mortem examination ascites, pleural effusions and telengectasies can guide the etiological diagnosis. We aim to further describe the perinatal presentation of this condition which could be underdiagnosed.

Successful palliative resection of giant epimyocardial lymphatic malformation with 14 years of follow-up: a case report.

BACKGROUND: Primary tumors of the heart are a rare phenomenon. Lymphatic malformations are congenital anomalies of the lymphatic system that tend to grow progressively. Lymphatic malformations are typically found in the cervical and axillary regions and found on pediatric patients. We report a 40-year-old woman with giant epimyocardial lymphatic malformation. CASE PRESENTATION: A 40-year-old woman was assessed due to suspected traumatic cardiac tamponade. Computed tomography of the heart and cardiac magnetic resonance imaging were compatible with either a large pericardial hemangioma or angiosarcoma. The tumor infiltrated deeply into the myocardium and could only be partially resected. Histopathological diagnosis was a cardiac lymphatic malformation with micro- and macrocystic components. The patient has remained asymptomatic for fourteen years after the surgery. In the latest follow-up, her left ventricular function had remained normal and the maximum thickness of the residual tumor had regressed. CONCLUSIONS: Even when a complete removal of a cardiac lymphatic malformation is not possible, a debulking procedure can yield a good long-term result.

Detection of superficial lymphatic malformation with dermoscopy and reflectance confocal microscopy.

BACKGROUND: Superficial lymphatic malformation (SLM) is a congenital disorder of the lymphatic channels. It usually appears as clusters of vesicles filled with lymphatic fluid and blood on the skin that resemble frogspawn, making it difficult to distinguish from haemangiomas, angiokeratomas, and pyogenic granulomas. Although pathological results have diagnostic values, the significance of noninvasive examination in the diagnosis and differential diagnosis is also worth exploring. MATERIALS AND METHODS: A 24-year-old female presented with a history of multiple asymptomatic, pink lesions located on the chest since age 10. Histopathological examination was performed, and results informed the diagnosis of SLM. Lesions were detected by dermoscopy and reflectance confocal microscopy (RCM). RESULTS: Dermoscopy (polarized, 30×) revealed multiple yellowish-red lacunae in a light red background that were separated by pale septa and "hypopyon sign" was observed. RCM displayed a honeycomb pattern and multiple dark cavities in the upper dermal layers separated by thin septa with a few hypo-refractile cells at the periphery that demonstrated slow fluid flow via dynamic scanning. CONCLUSION: We described a case of SLM detected by dermoscopy and RCM. Dermoscopic and RCM features may provide a potentially powerful, noninvasive instrument for the recognition and differentiation of SLM.

Curettage and sclerotherapy technique: A hybrid approach to superficial lymphatic malformation.

OBJECTIVE: To describe the curettage and sclerotherapy technique, a hybrid approach to treatment for superficial lymphatic malformations. METHODS: A retrospective analysis of a lymphatic malformation data base was performed. Patients with superficial lymphatic malformation treated by curettage and sclerotherapy technique with bleomycin were included in this study. Safety and efficacy of the curettage and sclerotherapy technique with bleomycin were evaluated. RESULTS: Between September 2019 and October 2021, 10 consecutive patients (male/female ratio: 4:6; mean age, 10.9 years; range, 3-35 years) presented with superficial lymphatic malformations that were subsequently treated by curettage and sclerotherapy technique with bleomycin. All lesions were located on the trunk and extremities. Each patient received one treatment session and a mean follow-up of 12 months. We observed minor complications. No postoperative infections occurred in this series. No patient developed skin ulceration or necrosis. Scarring and recurrence occurred in one patient. Complete regression was confirmed for all 10 patients by photographic evaluation. CONCLUSION: A curettage and sclerotherapy technique is proposed to treat superficial lymphatic malformation in this study. This technique seems to be safe and highly effective.

Spectrum of lymphatic anomalies in patients with RASA1-related CM-AVM.

BACKGROUND: Capillary malformation-arteriovenous malformation (CM-AVM) is characterized by multifocal fast-flow capillary malformations, sometimes with arteriovenous malformations/fistulas, skeletal/soft tissue overgrowth, telangiectasias, or Bier spots. Lymphatic abnormalities are infrequently reported. We describe seven patients with CM-AVM and lymphatic anomalies. METHODS: Following IRB approval, we identified patients with CM-AVM and lymphatic anomalies seen at the Vascular Anomalies Center at Boston Children's Hospital from 2003 to 2023. We retrospectively reviewed records for clinical, genetic, laboratory, and imaging findings. RESULTS: We found seven patients with CM-AVM and lymphatic abnormalities. Five patients were diagnosed prenatally: four with pleural effusions (including one suspected chylothorax) and one with ascites. Pleural effusions resolved after neonatal drainage in three patients and fetal thoracentesis in the fourth; however, fluid rapidly reaccumulated in this fetus causing hydrops. Ascites resolved after neonatal paracentesis, recurred at 2 months, and spontaneously resolved at 5 years; magnetic resonance lymphangiography for recurrence at age 19 years suggested a central conducting lymphatic anomaly (CCLA), and at age 20 years a right spermatic cord/scrotal lymphatic malformation (LM) was detected. Chylous pericardial effusion presented in a sixth patient at 2 months and disappeared after pericardiocentesis. A seventh patient was diagnosed with a left lower extremity LM at 16 months. Six patients underwent genetic testing, and all had RASA1 mutation. RASA1 variant was novel in three patients (c.1495delinsCTACC, c.434_451delinsA, c.2648del), previously reported in two (c.2603+1G>A, c.475_476del), and unavailable in another. Median follow-up age was 5.8 years (4 months-20 years). CONCLUSION: CM-AVM may be associated with lymphatic anomalies, including pericardial/pleural effusions, ascites, CCLA, and LM.

Impact of puberty on procedure frequency for treatment of simple head and neck lymphatic and venous malformations.

OBJECTIVE: Puberty has been shown to accelerate growth of vascular malformations, including lymphatic (LM) and venous malformations (VM). This study aims to compare the number of procedures performed before and after puberty in patients with LM and VM to assess whether the onset of puberty results in higher treatment frequency. METHODS: A retrospective review of head and neck LM and VM patients who were evaluated between January 2009 and December 2019 was performed. Patient demographics, lesion characteristics, and procedural details were recorded. For the purposes of this study, 11 years or older in females and 12 years or older in males were the established cut-offs for the onset of puberty. RESULTS: After initial screening of 357 patients, 83 patients were included in the study based on inclusion criteria. There were 34 patients with LM (41 %) and 49 with VM (59 %). The mean age at diagnosis was 6.1 ± 10.9 years (LM: 4.2 ± 7.0, VM: 7.4 ± 12.9, p = 0.489). 68 patients underwent treatments, which included sclerotherapy, surgical excision, and/or laser. For all patients, the average number of lifetime treatments when initiated before puberty was 3.78 ± 2.81 and when initiated after puberty was 2.17 ± 1.37 (p = 0.022). Patients diagnosed pre-puberty were more likely to undergo treatments vs. those diagnosed after puberty (OR 10.00, 95 % CI: 2.61-38.28, p < 0.001). CONCLUSION: We found that the number of treatments was fewer in those who started treatment after puberty. This finding suggests that providers may elect to proceed with observation in asymptomatic patients, given that waiting until after the onset of puberty has not shown an increase in the procedural load on patients.

Sirolimus treatment for paediatric head and neck lymphatic malformations: a systematic review.

PURPOSE: This PRISMA-compliant systematic review aimed to assess risks and benefits of sirolimus treatment for paediatric lymphatic malformations by focusing not only on treatment efficacy but also on possible treatment-related adverse events, and treatment combinations with other techniques. METHODS: Search criteria were applied to MEDLINE, Embase, Web of Science, Scopus, Cochrane Library, and ClinicalTrials.gov databases and included all studies published up to March 2022 reporting paediatric lymphatic malformations treated with sirolimus. We selected all original studies that included treatment outcomes. After the removal of duplicates, selection of abstracts and full-text articles, and quality assessment, we reviewed eligible articles for patient demographics, lymphatic malformation type, size or stage, site, clinical response rates, sirolimus administration route and dose, related adverse events, follow-up time, and concurrent treatments. RESULTS: Among 153 unique citations, 19 studies were considered eligible, with reported treatment data for 97 paediatric patients. Most studies (n = 9) were case reports. Clinical response was described for 89 patients, in whom 94 mild-to-moderate adverse events were reported. The most frequently administered treatment regimen was oral sirolimus 0.8 mg/m2 twice a day, with the aim of achieving a blood concentration of 10-15 ng/mL. CONCLUSION: Despite promising results for sirolimus treatment in lymphatic malformation, the efficacy and safety profile of remains unclear due to the lack of high-quality studies. Systematic reporting of known side effects, especially in younger children, should assist clinicians in minimising treatment-associated risks. At the same time, we advocate for prospective multicentre studies with minimum reporting standards to facilitate improved candidate selection.

Association between malformation type, location and functional deficits in lymphatic malformations of the head and neck in children.

PURPOSE: Lymphatic malformations (LM) are congenital malformations of the lymphatic system, mainly located in the head and neck area. They can be staged based on location according to de Serres and based on different morbidity items using the Cologne Disease Score (CDS), a clinical staging system. In many cases, functional impairment greatly affects the life of patients suffering from lymphatic malformations. The present study aims to analyze a cohort of pediatric patients with LM. METHODS: A retrospective analysis of 144 pediatric patients with head and neck LM was performed. Location, type of malformation (microcystic, macrocystic, mixed), scoring according to two different scoring systems and therapy were analyzed. Kruskal-Wallis test was used to analyze the difference in CDS between the patient groups and Dunn's test was used for post-hoc pairwise comparison. RESULTS: The average age at presentation was 6.1 years. The most common sites were neck (47%), cheek/parotid gland (26%), tongue (17%) and orbit (8%). Macrocystic malformations dominated the lateral neck, while microcystic malformations were predominantly localized in the tongue and floor of mouth. Macrocystic malformations (mean CDS 9.44) were associated with significantly better CDS than microcystic (mean CDS 7.11) and mixed (mean CDS 5.71) malformations (p < 0.001). LM in stage V according to de Serres had the lowest values (mean CDS: 4.26). The most common therapeutic procedures were conventional surgical (partial) resection, laser therapy and sclerotherapy with OK-432. CONCLUSIONS: There is an association between malformation type, location according to de Serres and CDS in children with LM of the head and neck. Patients with microcystic and mixed malformations in stage V had lowest CDS levels.

Clinical and Radiological Correlation of Low Flow Vascular Malformation Treated With Percutaneous Sclerotherapy.

Objective: To retrospectively correlate imaging findings post-sclerotherapy of low-flow vascular malformations with clinical outcome. Materials and Methods: We retrospectively evaluated 81 pediatric patients who had sclerotherapy in our department over a 14-year period. Patients with a diagnosis of low-flow vascular malformation, pre and post-treatment ultrasound (US) and clinical follow-up evaluation were included in the study. Exclusion criteria were coexisting high-flow vascular malformations, history of additional surgical or medical treatment to their malformation and large infiltrative lesions difficult to measure on US. Pre and post-treatment sonographic volumes of the malformation were assessed. Changes in volume were categorized into 6- increased volume, stable and volume decrease of 1-25%/26-50%/51-75%/75-100%. Clinical outcomes were categorized into 4 - worse, no change, improved and symptom free. In cases where pre-treatment MRI was available, the estimated malformation volumes in both modalities were correlated using Spearman's rank correlation. The change in sonographic volume was correlated with clinical outcome using Spearman's rank correlation. P-values < .05 were considered significant. Results: Twenty-nine patients were included in the study; 13 with venous malformation (VM), and 16 with lymphatic malformation (LM). Nineteen patients had both pre-treatment US and MRI, showing correlation in volume between the 2 modalities (P < .001). Post-treatment change in volume correlated with clinical outcome for combined venous and LMs (rho = .44, P = .02). No correlation was found when venous (rho = .48, P = .09) and lymphatic (rho = .33, P = .21) malformations were considered separately. Conclusion: Ultrasound can potentially be used as an objective tool in evaluating sclerotherapy treatment response of low-flow vascular malformations in the pediatric population.