Primary lymphedema French National Diagnosis and Care Protocol (PNDS; Protocole National de Diagnostic et de Soins)

Deep learning-based classification of lymphedema and other lower limb edema diseases using clinical images

Lymphedema is a chronic condition characterized by lymphatic fluid accumulation, primarily affecting the limbs. Its diagnosis is challenging due to symptom overlap with conditions like chronic venous insufficiency (CVI), deep vein thrombosis (DVT), and systemic diseases, often leading to diagnostic delays that can extend up to ten years. These delays negatively impact patient outcomes and burden healthcare systems. Conventional diagnostic methods rely heavily on clinical expertise, which may fail to distinguish subtle variations between these conditions. This study investigates the application of artificial intelligence (AI), specifically deep learning, to improve diagnostic accuracy for lower limb edema. A dataset of 1622 clinical images was used to train sixteen convolutional neural networks (CNNs) and transformer-based models, including EfficientNetV2, which achieved the highest accuracy of 78.6%. Grad-CAM analyses enhanced model interpretability, highlighting clinically relevant features such as swelling and hyperpigmentation. The AI system consistently outperformed human evaluators, whose diagnostic accuracy plateaued at 62.7%. The findings underscore the transformative potential of AI as a diagnostic tool, particularly in distinguishing conditions with overlapping clinical presentations. By integrating AI with clinical workflows, healthcare systems can reduce diagnostic delays, enhance accuracy, and alleviate the burden on medical professionals. While promising, the study acknowledges limitations, such as dataset diversity and the controlled evaluation environment, which necessitate further validation in real-world settings. This research highlights the potential of AI-driven diagnostics to revolutionize lymphedema care, bridging gaps in conventional methods and supporting healthcare professionals in delivering more precise and timely interventions. Future work should focus on external validation and hybrid systems integrating AI and clinical expertise for comprehensive diagnostic solutions.

Aging-induced changes in lymphatic muscle cell transcriptomes are associated with reduced pumping of peripheral collecting lymphatic vessels in mice

Lymphatic muscle cells (LMCs) within the wall of collecting lymphatic vessels exhibit tonic and autonomous phasic contractions, which drive active lymph transport to maintain tissue-fluid homeostasis and support immune surveillance. Damage to LMCs disrupts lymphatic function and is related to various diseases. Despite their importance, knowledge of the gene transcriptional signatures in LMCs and how they relate to lymphatic function in normal and disease contexts is largely missing. We have generated a comprehensive transcriptional single-cell atlas-including LMCs-of peripheral collecting lymphatic vessels from mice across the lifespan. We identified genes that distinguish LMCs from other types of muscle cells, characterized the phenotypical and transcriptomic changes in LMCs in aged vessels, and identified a proinflammatory microenvironment that suppresses the contractile apparatus in LMCs from advanced-aged mice. Our findings provide a valuable resource to accelerate future research for the identification of potential drug targets on LMCs to improve lymphatic vessel function.

Bilateral lower limbs swelling as uncommon manifestation of primary congenital lymphoedema: navigating diagnostic and therapeutic challenges in resource-limited Ende, Indonesia

This case report details a newborn in Ende, Indonesia, diagnosed with primary congenital lymphoedema, evidenced by bilateral lower limb swelling. This rare condition is characterised by developmental defects in the lymphatic system, leading to a fluid balance disruption. Diagnosis was primarily clinical, relying on thorough patient history and physical examination, given the limited resources for advanced diagnostic tools. The report emphasises the importance of supportive care, including meticulous skin care and manual lymph drainage, to improve life quality and minimise infection risks. It highlights the diagnostic and management challenges faced in low-resource settings and stresses the need for awareness and early intervention to manage such congenital conditions effectively.

Exploring the molecular mechanisms by which secretory phospholipase a2 regulates lymphatic endothelial cell dysfunction by activating macrophages

This study offers new insights into the dual role of secretory phospholipase A2 (sPLA2) in lymphedema, highlighting its impact on lymphatic endothelial cell (LEC) functionality. Through transcriptomic analyses and co-culture experiments, we observed that sPLA2 has both protective and detrimental effects on human LECs (HLECs), mediated by macrophage activation. Our findings reveal that while low levels of sPLA2 promote LEC health, excessive sPLA2 leads to dysfunction, emphasizing the significance of the sPLA2/PLA2R axis and arachidonic acid metabolism (AA) in lymphedema pathology. The study suggests targeting sPLA2 and its downstream pathways as a novel therapeutic strategy for lymphedema, aiming to mitigate its progression by safeguarding HLEC integrity. This research underscores the importance of balanced sPLA2 activity in maintaining lymphatic vessel health and presents a new avenue for lymphedema management and treatment.

Surgical Treatment for Primary Lymphedema: A Systematic Review of the Literature

This is a retrospective review of surgical management for primary lymphedema. Data were extracted from 55 articles from PubMed MEDLINE, Web of Science, SCOPUS, and Cochrane Central Register of Controlled Trials between the database inception and December 2022 to evaluate the outcomes of lymphaticovenous anastomosis (LVA) and vascularized lymph node transfer (VLNT), and outcomes of soft tissue extirpative procedures such as suction-assisted lipectomy (SAL) and extensive soft tissue excision. Data from 485 patients were compiled; these were treated with LVA ( n  = 177), VLNT ( n  = 82), SAL ( n  = 102), and excisional procedures ( n  = 124). Improvement of the lower extremity lymphedema index, the quality of life (QoL), and lymphedema symptoms were reported in most studies. LVA and VLNT led to symptomatic relief and improved QoL, reaching up to 90 and 61% average circumference reduction, respectively. Cellulitis reduction was reported in 25 and 40% of LVA and VLNT papers, respectively. The extirpative procedures, used mainly in patients with advanced disease, also led to clinical improvement from the volume reduction, as well as reduced incidence of cellulitis, although with poor cosmetic results; 87.5% of these reports recommended postoperative compression garments. The overall complication rates were 1% for LVA, 13% for VLNT, 11% for SAL, and 46% for extirpative procedures. Altogether, only one paper lacked some kind of improvement. Primary lymphedema is amenable to surgical treatment; the currently performed procedures have effectively improved symptoms and QoL in this population. Complication rates are related to the invasiveness of the chosen procedure.

[Update of indications and techniques for the management of lymphedema after breast cancer surgery]

OBJECTIVES

Upper limb lymphedema secondary to breast cancer treatment is the leading cause of lymphedema in France. Despite improved surgical practices and de-escalation of radiotherapy, the risk of lymphedema after breast cancer still affects 5-20% of patients, with this variation depending on the measurement method used and the population studied. Lymphedema has a negative impact on quality of life and body image, and their possible occurrence remains a major concern for all women treated for breast cancer. The Sénologie Commission of the Collège national des gynécologues et obstétriciens français (CNGOF) asked four specialists in breast surgery or lymphology to prepare a summary on the prevention, medical and surgical management of lymphedema after breast cancer treatment, and to discuss the medical and surgical innovations currently being evaluated.

METHODS

This synthesis was based on national and international guidelines on the management of upper limb lymphedema after breast surgery and a recent review of the literature focusing on the years 2020-2023.

RESULTS

From a preventive point of view, the restrictive instructions imposed for a long time (reduction in physical activity or the carrying of loads, air travel, exposure to the sun or cold, etc.) have altered patients' quality of life and should no longer be recommended. A good understanding of risk factors enables us to target preventive actions. Examples include obesity, a sedentary lifestyle, axillary clearance, radiotherapy of the axillary fossa in addition to axillary clearance, total mastectomy, taxanes or anti-HER-2 therapies in the adjuvant phase. Resumption of physical activity, minimally invasive axillary surgery, de-escalation of radiotherapy and breast-conserving surgical procedures have all demonstrated their preventive value. When lymphedema does occur, early management, through complete decongestive physiotherapy, can help reduce its volume and prevent its long-term worsening.

CONCLUSION

Surgical (lymph node transplants, lympho-vascular anastomoses) and medical (prolymphangiogenic growth factors) approaches to lymphedema treatment are numerous, but require long-term evaluation of their efficacy and adverse effects.

A multidisciplinary approach to managing lymphorroea in primary lymphoedema: a case study

This case study describes the successful management of a patient with primary lymphoedema, who was experiencing lymphorrhoea and epidermolysis, using a multidisciplinary approach. The patient had Klippel-Trenaunay syndrome. The multidisciplinary team, in an outpatient clinic in Japan, included a certified lymphoedema therapist, plastic surgeons, and a wound, ostomy and continence nurse. The team performed complex physical therapy and lymphaticovenular anastomosis, which promoted the resolution of the lymphorrhoea. This resulted in improvements in skin condition, the prevention of recurrent cellulitis, and no increase in limb circumferences during the 1-year follow-up period. This report highlights the importance of a multidisciplinary approach to lymphoedema management, including lymphorrhoea control that fitted in with the patient's daily life. It is hoped that this article will contribute to the improvement of the quality of life of patients with lymphoedema.

[Pretibial myxedema after Graves' disease: A differential diagnosis of lymphedema]

INTRODUCTION

Pretibial myxedema is a rare manifestation of Graves' disease, and pseudotumoral forms may be confused with lower limb lymphedema.

OBSERVATIONS

We reported 3 cases of pretibial myxedema in 2 women and 1 man, aged 72, 66, and 49 years, treated for Graves' disease 3, 25 and 32 years previously. Two patients were active smokers. Lymphedema diagnosis of the lower limbs was suspected in the presence of bilateral pseudotumoral lesions of the feet, toes and ankles and the presence of a Stemmer's sign (skin thickening at the base of the 2nd toe, pathognomonic of lymphedema). Lymphoscintigraphy in one case was normal, not confirming lymphedema.

CONCLUSION

Pretibial pseudotumoral myxedema is a differential diagnosis of lower limb lymphedema. This diagnosis is confirmed by questioning the patient about preexisting Graves' disease, the underlying etiology, to decide the appropriate treatment and to encourage cessation of smoking, which is a risk factor for pretibial myxedema.

Lymphatic muscle cells are unique cells that undergo aging induced changes

Lymphatic muscle cells (LMCs) within the wall of collecting lymphatic vessels exhibit tonic and autonomous phasic contractions, which drive active lymph transport to maintain tissue-fluid homeostasis and support immune surveillance. Damage to LMCs disrupts lymphatic function and is related to various diseases. Despite their importance, knowledge of the transcriptional signatures in LMCs and how they relate to lymphatic function in normal and disease contexts is largely missing. We have generated a comprehensive transcriptional single-cell atlas-including LMCs-of collecting lymphatic vessels in mouse dermis at various ages. We identified genes that distinguish LMCs from other types of muscle cells, characterized the phenotypical and transcriptomic changes in LMCs in aged vessels, and uncovered a pro-inflammatory microenvironment that suppresses the contractile apparatus in advanced-aged LMCs. Our findings provide a valuable resource to accelerate future research for the identification of potential drug targets on LMCs to preserve lymphatic vessel function as well as supporting studies to identify genetic causes of primary lymphedema currently with unknown molecular explanation.

Lymphedema and Kaposi sarcoma: A narrative review

BACKGROUND

Kaposi sarcoma (KS), due to HHV-8 infection is classified in 4 subtypes: epidemic, endemic, HIV-related and iatrogenic essentially after organ transplant. Lymphedema is a complication of KS. We reviewed the interactions between HHV-8 infection and lymphedema according an analysis of the literature.

MAIN BODY

HHV-8 can infect different types of cells, among them a privileged tropism for lymphatic endothelial cells. It induces multi-centric endothelial proliferation leading to the occlusion of lymphatic vascular lumen. Lymphatic obstruction progressively lead to the blockage of lymphatic drainage, lymph stasis and lymphedema. Lymphedema mostly involved the lower limb affected by KS. It can then develop simultaneously or after the appearance of KS lesions but also be the first sign of KS, a long time before KS skin lesion onset. Lymphedema diagnosis is clinical and lymphoscintigraphy can confirm it if necessary. Lymphedema may be associated with active lesions of KS or non-evolutive, with only cicatricial lesions. KS should be treated according to the KS subtype, aggressive form, with local or systemic treatments associating with causal treatment, such as HIV infection or reducing immuno-suppressive drugs in transplant patients. In most of the cases, KS treatment may slightly reduce (or not) lymphedema volume which remains a chronic disease. Lymphedema management should be associated in order to reduce the volume and then stabilizing it. Low-stretch bandage, elastic garments and skin care are the cornerstone of treatment.

CONCLUSION

Lymphedema is a frequent complication of KS, and may reveal KS or occurs throughout its course. Association of KS and lymphedema must be known because lymphedema is a chronic disease affecting the quality of life. Beyond the treatment of KS, its management must be specific including a long follow-up to optimize the patient's observance required to maintain the best lymphedema control.

Current Concepts in the Management of Primary Lymphedema

Primary lymphedema is a heterogeneous group of conditions encompassing all lymphatic anomalies that result in lymphatic swelling. Primary lymphedema can be difficult to diagnose, and diagnosis is often delayed. As opposed to secondary lymphedema, primary lymphedema has an unpredictable disease course, often progressing more slowly. Primary lymphedema can be associated with various genetic syndromes or can be idiopathic. Diagnosis is often clinical, although imaging can be a helpful adjunct. The literature on treating primary lymphedema is limited, and treatment algorithms are largely based on practice patterns for secondary lymphedema. The mainstay of treatment focuses on complete decongestive therapy, including manual lymphatic drainage and compression therapy. For those who fail conservative treatment, surgical treatment can be an option. Microsurgical techniques have shown promise in primary lymphedema, with both lymphovenous bypass and vascularized lymph node transfers demonstrating improved clinical outcomes in a few studies.

Consensus recommendations on lymphedema in Phelan-McDermid syndrome

Phelan-McDermid syndrome (PMS) is a neurodevelopmental disorder caused by deletions 22q13.3 or pathogenic variants in the SHANK3 gene. Lymphedema can be a clinical feature in 10-25% of individuals with PMS due to a deletion 22q13.3, but is not observed in those with a SHANK3 variant. This paper forms a part of the European consensus guideline for PMS and focuses on what is known regarding lymphedema in PMS in order to present clinical recommendations. The mechanism causing lymphedema in PMS is unknown. Lymphedema can be suggested by pitting oedema of the extremities or, in later stages, non-pitting swelling. It can occur already at a young age and be progressive if untreated, impacting daily functioning. Lymphedema can be treated using existing general multidisciplinary management guidelines, taking the functioning of the individual with PMS into account. Furthermore, well-known risk factors for the development of lymphedema as lack of physical activities and weight gain/obesity should be addressed. Diagnosis and treatment are best performed in a multidisciplinary centre of expertise.

Primary lymphoedema

Lymphoedema is the swelling of one or several parts of the body owing to lymph accumulation in the extracellular space. It is often chronic, worsens if untreated, predisposes to infections and causes an important reduction in quality of life. Primary lymphoedema (PLE) is thought to result from abnormal development and/or functioning of the lymphatic system, can present in isolation or as part of a syndrome, and can be present at birth or develop later in life. Mutations in numerous genes involved in the initial formation of lymphatic vessels (including valves) as well as in the growth and expansion of the lymphatic system and associated pathways have been identified in syndromic and non-syndromic forms of PLE. Thus, the current hypothesis is that most cases of PLE have a genetic origin, although a causative mutation is identified in only about one-third of affected individuals. Diagnosis relies on clinical presentation, imaging of the structure and functionality of the lymphatics, and in genetic analyses. Management aims at reducing or preventing swelling by compression therapy (with manual drainage, exercise and compressive garments) and, in carefully selected cases, by various surgical techniques. Individuals with PLE often have a reduced quality of life owing to the psychosocial and lifelong management burden associated with their chronic condition. Improved understanding of the underlying genetic origins of PLE will translate into more accurate diagnosis and prognosis and personalized treatment.

PIEZO1-gene gain-of-function mutations with lower limb lymphedema onset in an adult: Clinical, scintigraphic, and noncontrast magnetic resonance lymphography findings

Primary lymphedema, a rare disease, has a genetic cause in ~40% of patients. Recently, loss-of-function mutations in PIEZO1, which encodes the mechanotransducer protein PIEZO1, were described as causing primary lymphedema, when gain-of-function PIEZO1 mutations were attributed to dehydrated hereditary stomatocytosis type-1 (DHS), a dominant red cell hemolytic disorder, with ~20% of patients having perinatal edema. Lymphedema was diagnosed in a 36-year-old man from a three-generation DHS family, with a PIEZO1-allele harboring 3 missense mutations in cis. Four affected family members had severe fetal and neonatal edema, most severe in the proband, whose generalized edema with prevailing ascites resolved after 8 months. Our patient's intermittent lower limb-lymphedema episodes during hot periods appeared at puberty; they became persistent and bilateral at age 32. Clinical Stemmer's sign confirmed lymphedema. Lower leg lymphoscintigraphy showed substantial dermal backflow in both calves, predominantly on the right. Noncontrast magnetic resonance lymphography showed bilateral lower limb lymphedema, dilated dysplastic lymphatic iliac, and inguinal trunks. Exome-sequencing analysis identified no additional pathogenic variation in primary lymphedema-associated genes. This is the first description of well-documented lymphedema in an adult with PIEZO1-DHS. The pathophysiology of PIEZO1-associated primary lymphedema is poorly understood. Whether it infers overlapping phenotypes or different mechanisms of gain- and loss-of-function PIEZO1 mutations deserves further investigation.