Magnetic resonance lymphangiography: Establishing normal.

BACKGROUND: Despite an increased interest in visualizing the lymphatic vessels with magnetic resonance lymphangiography (MRL), little literature is available describing their appearance in nonlymphedematous individuals. To determine lymphatic abnormalities, an understanding of how healthy lymphatic vessels appear and behave needs to be established. Therefore, in this study, MRL of individuals without a history of lymphatic disease was performed. METHODS: A total of 25 individuals (15 women) underwent MRL of their lower limbs using a 3.0 T Philips magnetic resonance imaging scanner (Philips Medical Systems). The first nine participants were recruited to establish the concentration of gadolinium-based contrast agent (GBCA) to administer, with the remainder imaged before and after interdigital forefoot GBCA injections at the optimized dose. Outcomes, including lymphatic vessel diameter, tortuosity, and frequency of drainage via particular drainage routes, were recorded. RESULTS: Healthy lymphatic vessels following the anteromedial pathway were routinely observed in post-contrast T1-weighted images (average tortuosity, 1.09 ± 0.03), with an average of 2.16 ± 0.93 lymphatic vessels with a diameter of 2.47 ± 0.50 mm crossing the anterior ankle. In six limbs, vessels following the anterolateral pathways were observed. No vessels traversing the posterior of the legs were seen. In a subset of 10 vessels, the lymphatic signal, measured at the ankle, peaked 29 minutes, 50 seconds ± 9 minutes, 29 seconds after GBCA administration. No lymphatic vessels were observed in T2-weighted images. CONCLUSIONS: Contrast-enhanced MRL reliably depicts the lymphatic vessels in the legs of healthy controls. Following interdigital contrast injection, anteromedial drainage appears dominant. Quantitative measures related to lymphatic vessel size, tortuosity, and drainage rate are readily obtainable and could be beneficial for detecting even subtle lymphatic impairment.

LymphActiv: A Digital Physical Activity Behavior Intervention for the Treatment of Lymphedema and Lipedema.

Background: Lymphedema and lipedema are debilitating conditions with no proven drug or surgical therapy. Effective treatment requires self-management through movement and compression to reduce limb volume and the incidence of cellulitis. The addition of personalized everyday physical activity (PA) could be transformative, increasing the therapy window to include all waking hours per week and enabling an increased dose of PA. Aim: This service evaluation aimed to determine the feasibility of LymphActiv as a treatment option for lymphedema and lipedema patients. Methods: This service evaluation followed an open observational cohort design, including 55 patients who participated in LymphActiv over 24 weeks. Patients wore an objective PA monitor and interacted with their data in an online dashboard, alongside remote mentor support. Primary outcomes were changes to PA, body weight, limb volume and quality of life. Clinical assessments occurred at baseline and after the 24-week program. Noncompleters were used as a quasi-control group for comparison. Results: Thirty-seven patients completed, of which 81% improved PA. On average, completers reduced their right and left lower limb volumes by -1.8% and -2.1%, respectively. Completers also experienced small average weight losses of -1.2 kg. Noncompleters experienced small average increases in each of these outcome measures. Discussion: These results establish the value of LymphActiv, providing benefit to patients who might otherwise have deteriorated. For services, this could lead to substantial cost-savings through reduced admissions, greater patient independence, and less need for community health care input. The next step is to undertake a randomized, controlled trial comparing the intervention with standard care.

Erythematous capillary-lymphatic malformations mimicking blood vascular anomalies.

Superficial erythematous cutaneous vascular malformations are assumed to be blood vascular in origin, but cutaneous lymphatic malformations can contain blood and appear red. Management may be different and so an accurate diagnosis is important. Cutaneous malformations were investigated through 2D histology and 3D whole-mount histology. Two lesions were clinically considered as port-wine birthmarks and another 3 lesions as erythematous telangiectasias. The aims were (i) to demonstrate that cutaneous erythematous malformations including telangiectasia can represent a lymphatic phenotype, (ii) to determine if lesions represent expanded but otherwise normal or malformed lymphatics, and (iii) to determine if the presence of erythrocytes explained the red color. Microscopy revealed all lesions as lymphatic structures. Port-wine birthmarks proved to be cystic lesions, with nonuniform lymphatic marker expression and a disconnected lymphatic network suggesting a lymphatic malformation. Erythematous telangiectasias represented expanded but nonmalformed lymphatics. Blood within lymphatics appeared to explain the color. Blood-lymphatic shunts could be detected in the erythematous telangiectasia. In conclusion, erythematous cutaneous capillary lesions may be lymphatic in origin but clinically indistinguishable from blood vascular malformations. Biopsy is advised for correct phenotyping and management. Erythrocytes are the likely explanation for color accessing lymphatics through lympho-venous shunts.

Self-care treatment for lymphoedema of lymphatic filariasis using integrative medicine.

BACKGROUND: Lymphatic filariasis (LF) is a neglected tropical disease presenting mainly as lymphoedema (elephantiasis). At present, LF is not effectively treated. Integrative medicine (IM) treatment for lymphoedema uses a combination of Indian traditional medicine, Ayurveda, alongside yoga exercises, compression therapy, antibiotics and antifungal treatments, providing a useful combination where resources are limited and different practices are in use. OBJECTIVES: To assess the effectiveness of the IM in the existing clinical practice of lower-limb lymphoedema management and to determine whether the treatment outcomes align with the World Health Organization (WHO) global goal of LF management. METHODS: Institutional data from electronic medical records of all 1698 patients with LF between 2010 and 2019 were retrospectively analysed using pre- and post-treatment comparisons and the National Institute for Health and Care Excellence guidelines for clinical audit. The primary treatment outcomes evaluated were limb volume, bacterial entry points (BEEPs), episodes of cellulitis, and health-related quality of life (HRQoL). Secondary outcomes included the influence of the patient's sex, duration of illness, education and employment status on volume reduction. Multiple regression analysis, t-test, χ2-test, analysis of variance, Mann-Whitney U-test and the Kruskal-Wallis test were used to assess the association between IM and patients' treatment outcomes. RESULTS: Limb volume reduced by 24.5% [95% confidence interval (CI) 22.47-26.61; n = 1660] following an intensive supervised care period (mean 14.84 days, n = 1660). Limb volume further reduced by 1.42% (95% CI 0.76-2.07; n = 1259) at the first follow-up visit (mean 81.45 days), and by 2.3% between the first and second follow-up visits (mean 231.32 days) (95% CI 1.26-3.34; n = 796). BEEPs were reduced upon follow-up; excoriations (78.4%) and intertrigo (26.7%) were reduced at discharge and further improvements was achieved at the follow-up visits. In total, 4% of patients exhibited new BEEPs at the first follow-up [eczema (3.9%), folliculitis (6.5%), excoriations (11.9%) and intertrigo (15.4%); 4 of 7 BEEPs were recorded]. HRQoL, measured using the disease-specific Lymphatic Filariasis Specific Quality of Life Questionnaire, showed an average score of 73.9 on admission, which increased by 17.8 at the first follow-up and 18.6 at the second follow-up. No patients developed new cellulitis episodes at the first follow-up, and only five patients (5.3%) developed new episodes of cellulitis at the second follow-up. CONCLUSIONS: IM for lower-limb lymphoedema successfully reduces limb volume and episodes of cellulitis, and also reduces BEEPs, leading to improved HRQoL. IM aligns with the LF treatment goals of the WHO and is a low-cost, predominantly self-care management protocol. IM has the potential to change care models and improve the lives of patients with lymphoedema.

Image registration and subtraction in dynamic magnetic resonance lymphangiography (MRL) of the legs.

Dynamic contrast-enhanced magnetic resonance lymphangiography (DCE-MRL) is regularly reported as unable to depict lymphatic vessels in healthy limbs. In this study, we aim to improve lymph vessel conspicuity with appropriate registration and subtraction of a reference baseline image. Five unaffected individuals and a single unilateral primary lymphoedema patient were recruited to undergo fat suppressed 3D T 1 weighted spoiled gradient echo imaging of the lower limbs at 3.0 T. Images were quality assessed by two physicians and a medical physicist following registration via one of six registration pipelines, and subtraction of the first post-contrast dynamic image (PC1). Wilcoxon non-parametric testing was performed to compare image quality ranking vs the unregistered images and inter-rater reliability estimated using intraclass correlation coefficient. Signal enhancement curves were also computed in lymphatic vessels for two participants. Subtraction images were considered to improve lymphatic visibility, and three registration pipelines significantly (p < 0.05) outranked those without registration. Those registered to PC1 with an affine and elastic approach were rated best quality (p = 0.006). Moderate inter-rater reliability was observed (intraclass correlation coefficient = 0.71) and signal enhancement behaviour appears affected by registration when motion is evident across the DCE-MRL series. We therefore conclude that lymphatic vessel visibility in DCE-MRL images can be improved with registration and baseline subtraction.

Case Report: Progressive central conducting lymphatic abnormalities in the RASopathies. Two case reports, including successful treatment by MEK inhibition.

The RASopathies are a group of genetic conditions resulting from mutations within the RAS/mitogen-activated protein kinase (RAS-MAPK) pathway. Lymphatic abnormalities are commonly associated with these conditions, however central conducting lymphatic abnormalities (CCLA) have only recently been described. CCLAs may be progressive and can result in devastating systemic sequelae, such as recurrent chylothoraces, chylopericardium and chylous ascites which can cause significant morbidity and even mortality. Improvements in imaging modalities of the central lymphatics have enhanced our understanding of these complex abnormalities. Management is challenging and have mainly consisted of diuretics and invasive mechanical drainages. We describe two adult males with Noonan syndrome with a severe and progressive CCLA. In one patient we report the therapeutic role of targeted molecular therapy with the MEK inhibitor 'Trametinib', which has resulted in dramatic, and sustained, clinical improvement. The successful use of MEK inhibition highlights the importance of understanding the molecular cause of lymphatic abnormalities and utilising targeted therapies to improve quality of life and potentially life expectancy.

Investigation of clinical characteristics and genome associations in the 'UK Lipoedema' cohort.

Lipoedema is a chronic adipose tissue disorder mainly affecting women, causing excess subcutaneous fat deposition on the lower limbs with pain and tenderness. There is often a family history of lipoedema, suggesting a genetic origin, but the contribution of genetics is currently unclear. A tightly phenotyped cohort of 200 lipoedema patients was recruited from two UK specialist clinics. Objective clinical characteristics and measures of quality of life data were obtained. In an attempt to understand the genetic architecture of the disease better, genome-wide single nucleotide polymorphism (SNP) genotype data were obtained, and a genome wide association study (GWAS) was performed on 130 of the recruits. The analysis revealed genetic loci suggestively associated with the lipoedema phenotype, with further support provided by an independent cohort taken from the 100,000 Genomes Project. The top SNP rs1409440 (ORmeta ≈ 2.01, Pmeta ≈ 4 x 10-6) is located upstream of LHFPL6, which is thought to be involved with lipoma formation. Exactly how this relates to lipoedema is not yet understood. This first GWAS of a UK lipoedema cohort has identified genetic regions of suggestive association with the disease. Further replication of these findings in different populations is warranted.

Janus-faced EPHB4-associated disorders: novel pathogenic variants and unreported intrafamilial overlapping phenotypes.

PURPOSE: Several clinical phenotypes including fetal hydrops, central conducting lymphatic anomaly or capillary malformations with arteriovenous malformations 2 (CM-AVM2) have been associated with EPHB4 (Ephrin type B receptor 4) variants, demanding new approaches for deciphering pathogenesis of novel variants of uncertain significance (VUS) identified in EPHB4, and for the identification of differentiated disease mechanisms at the molecular level. METHODS: Ten index cases with various phenotypes, either fetal hydrops, CM-AVM2, or peripheral lower limb lymphedema, whose distinct clinical phenotypes are described in detail in this study, presented with a variant in EPHB4. In vitro functional studies were performed to confirm pathogenicity. RESULTS: Pathogenicity was demonstrated for six of the seven novel EPHB4 VUS investigated. A heterogeneity of molecular disease mechanisms was identified, from loss of protein production or aberrant subcellular localization to total reduction of the phosphorylation capability of the receptor. There was some phenotype-genotype correlation; however, previously unreported intrafamilial overlapping phenotypes such as lymphatic-related fetal hydrops (LRFH) and CM-AVM2 in the same family were observed. CONCLUSION: This study highlights the usefulness of protein expression and subcellular localization studies to predict EPHB4 variant pathogenesis. Our accurate clinical phenotyping expands our interpretation of the Janus-faced spectrum of EPHB4-related disorders, introducing the discovery of cases with overlapping phenotypes.

Systematic Review of Magnetic Resonance Lymphangiography From a Technical Perspective.

BACKGROUND: Clinical examination and lymphoscintigraphy are the current standard for investigating lymphatic function. Magnetic resonance imaging (MRI) facilitates three-dimensional (3D), nonionizing imaging of the lymphatic vasculature, including functional assessments of lymphatic flow, and may improve diagnosis and treatment planning in disease states such as lymphedema. PURPOSE: To summarize the role of MRI as a noninvasive technique to assess lymphatic drainage and highlight areas in need of further study. STUDY TYPE: Systematic review. POPULATION: In October 2019, a systematic literature search (PubMed) was performed to identify articles on magnetic resonance lymphangiography (MRL). FIELD STRENGTH/SEQUENCE: No field strength or sequence restrictions. ASSESSMENT: Article quality assessment was conducted using a bespoke protocol, designed with heavy reliance on the National Institutes of Health quality assessment tool for case series studies and Downs and Blacks quality checklist for health care intervention studies. STATISTICAL TESTS: The results of the original research articles are summarized. RESULTS: From 612 identified articles, 43 articles were included and their protocols and results summarized. Field strength was 1.5 or 3.0 T in all studies, with 25/43 (58%) employing 3.0 T imaging. Most commonly, imaging of the peripheries, upper and lower limbs including the pelvis (32/43, 74%), and the trunk (10/43, 23%) is performed, including two studies covering both regions. Imaging protocols were heterogenous; however, T2 -weighted and contrast-enhanced T1 -weighted images are routinely acquired and demonstrate the lymphatic vasculature. Edema, vessel, quantity and morphology, and contrast uptake characteristics are commonly reported indicators of lymphatic dysfunction. DATA CONCLUSION: MRL is uniquely placed to yield large field of view, qualitative and quantitative, 3D imaging of the lymphatic vasculature. Despite study heterogeneity, consensus is emerging regarding MRL protocol design. MRL has the potential to dramatically improve understanding of the lymphatics and detect disease, but further optimization, and research into the influence of study protocol differences, is required before this is fully realized. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Development and physiological functions of the lymphatic system: insights from human genetic studies of primary lymphedema.

Primary lymphedema is a long-term (chronic) condition characterized by tissue lymph retention and swelling that can affect any part of the body, although it usually develops in the arms or legs. Due to the relevant contribution of the lymphatic system to human physiology, while this review mainly focuses on the clinical and physiological aspects related to the regulation of fluid homeostasis and edema, clinicians need to know that the impact of lymphatic dysfunction with a genetic origin can be wide ranging. Lymphatic dysfunction can affect immune function so leading to infection; it can influence cancer development and spread, and it can determine fat transport so impacting on nutrition and obesity. Genetic studies and the development of imaging techniques for the assessment of lymphatic function have enabled the recognition of primary lymphedema as a heterogenic condition in terms of genetic causes and disease mechanisms. In this review, the known biological functions of several genes crucial to the development and function of the lymphatic system are used as a basis for understanding normal lymphatic biology. The disease conditions originating from mutations in these genes are discussed together with a detailed clinical description of the phenotype and the up-to-date knowledge in terms of disease mechanisms acquired from in vitro and in vivo research models.

The St George's Classification Algorithm of Primary Lymphatic Anomalies.

Clinicians and scientists at St George's University Hospital have collaborated to develop a classification algorithm for primary lymphatic anomalies. Instruction is offered on how to apply the algorithm in clinical practice to refine the diagnosis of primary lymphedema and guide on genetic testing and management. It can also be used to interpret mutation testing results of uncertain significance. The algorithm has evolved as more genes have been discovered, and it remains a "work in progress" as further discoveries are made. This transformational approach has revolutionized the understanding and classification of primary lymphatic anomalies.

Axillary Web Syndrome: Evidence for Lymphatic Origin with Thrombosis.

Background: The axillary web syndrome (AWS) occurs in the axilla and on the frontal side of the upper arm and sometimes along the forearm to the thumb. The cord is painful, particularly on movement, and can therefore be very distressing for the patient. Although the phenomenon has been examined and discussed for decades, no evidence for the origin has been found until now. The aim of this study was to perform a histopathologic analysis of cords taken between 1996 and 1998 in the Surgical Clinic, Skane University Hospital, Lund, Sweden. Methods and Results: In seven patients, biopsies of the AWS cords were obtained 4-5 weeks after axillary node surgery for breast cancer and examined with standard hematoxylin and eosin and D2-40 (lymphatic endothelial cell) staining. In one biopsy, there was a dilated vessel with a thickened wall, which was confirmed by D2-40 immunostaining to represent a lymphatic vessel. The lumen was occluded by organized thrombus, within which new vessels were being formed, indicating recanalization. In two other biopsies, similar lymphatic vessels with thickened walls were present, although the lumen of the vessels was not visualized in the planes of the section. The other four biopsies do not show specific features. Conclusion: Although only one case, this is the first pathological evidence of thrombosis within a confirmed lymphatic vessel from a case of cording. We propose that the axillary cord represents lymphatic vessel thrombosis. Recanalization of the thrombus may eventually restore lymphatic flow consistent with the transient nature of the condition.

Lymphoscintigraphic Abnormalities Associated with Milroy Disease and Lymphedema-Distichiasis Syndrome.

Background: Primary lymphedema is genetically heterogeneous. Two of the most common forms of primary lymphedema are Milroy disease (MD) and lymphedema-distichiasis syndrome (LDS). This study aims to look further into the pathogenesis of the two conditions by analyzing the lymphoscintigram images from affected individuals to ascertain if it is a useful diagnostic tool. Methods and Results: The lymphoscintigrams of patients with MD and LDS were analyzed, comparing the images and transport parameters of the two genotypes against a control population. Lymphoscintigrams were available for 12 MD and 16 LDS patients (all genetically proven diagnoses). Eight of the 12 (67%) lymph scans performed on patients with MD demonstrated little or no uptake from the initial lymphatics and poor visualization of the inguinal lymph nodes. These changes were consistent with a "functional aplasia," that is, the lymphatic vessels were present but appeared to be ineffective in absorbing the interstitial fluid into the lymphatic system. In patients with LDS the lymphoscintigraphic appearances were different. In 12 of the 16 scans (75%), the lymph scans were highly suggestive of lymphatic collector reflux. Quantification revealed a significantly reduced uptake of tracer within the inguinal lymph nodes and a higher residual activity in the feet at 2 hours in MD compared with LDS and compared with controls. Conclusion: Lymphoscintigraphic imaging and quantification can be characteristic in specific genetic forms of primary lymphedema and may be useful as an additional tool for in-depth phenotyping, leading to a more accurate diagnosis and providing insight into the underlying mechanism of disease.

Author Correction: Novel mutations in PIEZO1 cause an autosomal recessive generalized lymphatic dysplasia with non-immune hydrops fetalis.

This Article contains an error in the last sentence of the 'Variant analysis suggests they are pathogenic' section of the Results, which incorrectly reads 'No truncated PIEZO1 protein products were identified in western blot analysis in GLD1:II.3 and GLD2:II.2 (Fig. 2, Supplementary Fig. 6), suggesting that the truncated protein is not stable and therefore degraded.' This should read 'No full-size PIEZO1 protein products were identified in western blot analysis in GLD1:II.3 and GLD2:II.2 (Fig. 2, Supplementary Fig. 6); the three nonsense mutations are predicted to lead to premature termination of the protein, hence it is possible that those truncated proteins will be non-functional or even unstable and degraded.' The error has not been fixed in the PDF or HTML versions of the Article.

A Novel Splice-Site Mutation in VEGFC Is Associated with Congenital Primary Lymphoedema of Gordon.

Lymphedema is characterized by chronic swelling of any body part caused by malfunctioning or obstruction in the lymphatic system. Primary lymphedema is often considered genetic in origin. VEGFC, which is a gene encoding the ligand for the vascular endothelial growth factor receptor 3 (VEGFR3/FLT4) and important for lymph vessel development during lymphangiogenesis, has been associated with a specific subtype of primary lymphedema. Through Sanger sequencing of a proband with bilateral congenital pedal edema resembling Milroy disease, we identified a novel mutation (NM_005429.2; c.361+5G>A) in VEGFC. The mutation induced skipping of exon 2 of VEGFC resulting in a frameshift and the introduction of a premature stop codon (p.Ala50ValfsTer18). The mutation leads to a loss of the entire VEGF-homology domain and the C-terminus. Expression of this Vegfc variant in the zebrafish floorplate showed that the splice-site variant significantly reduces the biological activity of the protein. Our findings confirm that the splice-site variant, c.361+5G>A, causes the primary lymphedema phenotype in the proband. We examine the mutations and clinical phenotypes of the previously reported cases to review the current knowledge in this area.

A Case-Control Study of the Lymphatic Phenotype of Yellow Nail Syndrome.

BACKGROUND: Yellow nail syndrome (YNS) is a rare disease manifesting as a triad of yellow-green dystrophic nails, lymphedema, and chronic respiratory disease. The etiology of YNS is obscure and investigations are few. A single lymphatic pathogenesis has been proposed to account for all the associated features, and despite the lack of evidence for a unifying lymphatic mechanism, this hypothesis prevails. The objective was to explore the lymphatic phenotype in YNS and to establish whether lymphatic dysfunction could be a major contributing factor to the disease process. METHODS AND RESULTS: Four-limb lymphoscintigraphy was performed on patients with YNS and on healthy, age-matched controls. All 17 patients had lower limb swelling, and 14 (82%) had upper limb swelling also, including 5 (29%) with hand involvement. None of the YNS lymph scans was completely normal. Combined qualitative and quantitative assessment showed that 67% of YNS scans were clearly abnormal compared with 36% of healthy control scans. Mean axillary and ilio-inguinal nodal tracer uptakes were 41%-44% lower in the YNS group than in the controls (p < 0.0001). CONCLUSIONS: YNS is a lymphatic phenotype because lymphatic insufficiency was found to exist in all patients and the insufficiency was widespread (upper and lower limbs), with a common mechanistic fault of poor transport. The origin of the lymphatic fault is unclear. In healthy individuals, lymphatic abnormalities may be relatively common in the fifth decade of life onward.

Community-Based Treatment for Chronic Edema: An Effective Service Model.

BACKGROUND: Chronic edema care is patchy and of variable quality internationally. This study was undertaken to develop and evaluate a system of care that would provide for patients within a geographical area of London (Wandsworth), United Kingdom. METHODS AND RESULTS: A prospective cohort design with intervention of a new service design following a 6-month baseline period. Patients were identified through health professionals. A stratified random sample was drawn from all patients and an implementation strategy developed. Clinical assessment combined with questionnaires evaluated clinical, patient, and health service outcomes at 6-month periods. In all, 312 patients were identified in community and acute services giving a crude ascertainment rate of 1.16 per 1000 population. The random sample of 107 was mostly female (82%) with mean (standard deviation) age of 72.9 (12.4) in men and 68.6 (15.0) years in women. Mean reductions in limb volume achieved statistical differences at 6-12 months after implementation (difference [d] = 115 mL, p = 0.0001). Incidence of cellulitis dropped from 41.5/100 patient years at baseline to zero at 6-12 months. Quality of life showed greatest improvements between baseline and 6 months postimplementation, the largest differences being in role physical (d = 32.7, p = 0.0001) and role emotion (d = 24.0, p < 0.0001). EuroQol increased following implementation by a mean score of 0.05 (p = 0.007). There was a reduction in 6 monthly healthcare costs from £50171 per 100 patients at baseline to £17618 between 6 and 12 months. CONCLUSIONS: This process of implementation improves health outcomes while reducing healthcare costs in patients with lymphedema.