How we approach the diagnosis and management of complex lymphatic anomalies

Kaposiform Lymphangiomatosis as a Cause of Vaginal Bleeding & Discharge: A Case Report

BACKGROUND

Prepubertal vaginal bleeding is a common presentation for pediatric adolescent gynecologists with a broad differential diagnosis that historically may not have included complex lymphatic anomalies. However, given recent consensus criteria and imaging capabilities, this may be a condition that pediatric adolescent gynecologists see more frequently in the future.

CASE

We present a case of a 5-year-old pre-pubertal girl whose only presenting symptoms of a rare complex lymphatic anomaly was copious vaginal bleeding. After three vaginoscopies, two hysteroscopies, two pelvic MRIs, and a percutaneous ultrasound guided core needle biopsy, this patient was eventually diagnosed with Kaposiform lymphangiomatosis at age 9 years-old, and she is now being treated medically with sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, with improvement in her symptoms.

SUMMARY AND CONCLUSION

Complex lymphatic anomalies should be considered after initial and secondary workups for pre-pubertal vaginal bleeding or copious vaginal discharge are negative. Furthermore, this case illustrates the value of pelvic MRI in the setting of unknown cause of vaginal bleeding when typical workup is negative.

Complex lymphatic anomalies: Molecular landscape and medical management

The lymphatic system is one of the most essential and complex systems in the human body. Disorders that affect the development or function of the lymphatic system can lead to multi-system complications and life-long morbidity. The past two decades have seen remarkable progress in our knowledge of the basic biology and function of the lymphatic system, the molecular regulators of lymphatic development, and description of disorders associated with disrupted lymphangiogensis. In this chapter we will touch on the clinical features of complex lymphatic anomalies, new molecular knowledge of the drivers of these disorders, and novel developmental therapeutics for lymphatic disease.

Lymphatic failure and lymphatic interventions: Knowledge gaps and future directions for a new frontier in congenital heart disease

Lymphatic failure is a broad term that describes the lymphatic circulation's inability to adequately transport fluid and solutes out of the interstitium and into the systemic venous circulation, which can result in dysfunction and dysregulation of immune responses, dietary fat absorption, and fluid balance maintenance. Several investigations have recently elucidated the nexus between lymphatic failure and congenital heart disease, and the associated morbidity and mortality is now well-recognized. However, the precise pathophysiology and pathogenesis of lymphatic failure remains poorly understood and relatively understudied, and there are no targeted therapeutics or interventions to reliably prevent its development and progression. Thus, there is growing enthusiasm towards the development and application of novel percutaneous and surgical lymphatic interventions. Moreover, there is consensus that further investigations are needed to delineate the underlying mechanisms of lymphatic failure, which could help identify novel therapeutic targets and develop innovative procedures to improve the overall quality of life and survival of these patients. With these considerations, this review aims to provide an overview of the lymphatic circulation and its vasculature as it relates to current understandings into the pathophysiology and pathogenesis of lymphatic failure in patients with congenital heart disease, while also summarizing strategies for evaluating and managing lymphatic complications, as well as specific areas of interest for future translational and clinical research efforts.

Central conducting lymphatic anomaly: from bench to bedside

Central conducting lymphatic anomaly (CCLA) is a complex lymphatic anomaly characterized by abnormalities of the central lymphatics and may present with nonimmune fetal hydrops, chylothorax, chylous ascites, or lymphedema. CCLA has historically been difficult to diagnose and treat; however, recent advances in imaging, such as dynamic contrast magnetic resonance lymphangiography, and in genomics, such as deep sequencing and utilization of cell-free DNA, have improved diagnosis and refined both genotype and phenotype. Furthermore, in vitro and in vivo models have confirmed genetic causes of CCLA, defined the underlying pathogenesis, and facilitated personalized medicine to improve outcomes. Basic, translational, and clinical science are essential for a bedside-to-bench and back approach for CCLA.

Medical Management and Therapeutic Updates on Vascular Anomalies of the Head and Neck: Part 2

Discovery of inherited and somatic genetic mutations, along with advancements in clinical and scientific research, has improved understanding of vascular anomalies and changed the treatment paradigm. With aim of minimizing need for invasive procedures and improving disease outcomes, molecularly targeted medications and anti-angiogenesis agents have become important as both adjuncts to surgery, and increasingly, as the primary treatment of vascular anomalies. This article highlights the commonly used and emerging therapeutic medications for non-malignant vascular tumors and vascular malformations in addition to medical management of associated hematologic abnormalities.

Complex lymphatic anomalies: Challenging diagnostic considerations

Diagnosis of complex lymphatic anomalies can be difficult, and biopsies can be associated with significant morbidity. Mediastinal masses with features such as osseous involvement warrant thorough noninvasive evaluation prior to biopsy.

Treatment of severe Kaposiform lymphangiomatosis positive for NRAS mutation by MEK inhibition

BACKGROUND

Kaposiform lymphangiomatosis (KLA) is a complex lymphatic anomaly involving most commonly the mediastinum, lung, skin and bones with few effective treatments. In recent years, RAS-MAPK pathway mutations were shown to underlie the pathogenesis of several complex lymphatic anomalies. Specifically, an activating NRAS mutation (p.Q61R) was found in the majority of KLA patients. Recent reports demonstrated promising results of treatment with the MEK inhibitor, Trametinib, in patients with complex lymphatic anomalies harboring gain of function mutations in ARAF and SOS1, as well as loss of function mutation in the CBL gene, a negative regulator of the RAS-MAPK pathway. We present a 9-year-old child with a severe case of KLA harboring the typical NRAS (p.Q61R) mutation detected by plasma-derived cell free DNA, responsive to trametinib therapy.

METHODS

The NRAS somatic mutation was detected from plasma cfDNA using droplet digital PCR. Concurrent in-vitro studies of trametinib activity on mutant NRAS affected lymphatic endothelial cells were performed using a three-dimensional spheroid sprouting assay.

RESULTS

Trametinib treatment lead to resolution of lifelong thrombocytopenia, improvement of pulmonary function tests and wellbeing, as well as weaning from prolonged systemic steroid treatment. Concurrent studies of mutant NRAS-expressing cells showed enhanced lymphangiogenic capacity along with over activation of the RAS-MAPK and PI3K-AKT-mTOR pathways, both reversed by trametinib.

CONCLUSIONS

Trametinib treatment can substantially change the prognosis of patients with RAS pathway associated lymphatic anomalies.

IMPACT

This is the first description of successful trametinib treatment of a patient with KLA harboring the most characteristic NRAS p.Q61R mutation. Treatment can significantly change the prognosis of patients with RAS pathway-associated lymphatic anomalies. We devised an in vitro model of KLA enabling a reproducible method for the continued study of disease pathogenesis. Mutated NRAS p.Q61R cells demonstrated increased lymphangiogenic capacity.

Solid and Vascular Neck Masses in Children

Neck masses are frequent in the pediatric population and are usually divided into congenital, inflammatory, and neoplastic. Many of these lesions are cystic and are often benign. Solid masses and vascular lesions are relatively less common, and the imaging appearances can be similar. This article reviews the clinical presentation and imaging patterns of pediatric solid and vascular neck masses.

Cough-induced chylothorax in a two-year-old boy - case report and review of the literature

BACKGROUND

Chylothorax is a very rare form of pleural effusion in children, especially after the neonatal period, and predominantly occurs secondary to cardiothoracic surgery. It can lead to significant respiratory distress, immunodeficiency, and malnutrition. Effective treatment strategies are therefore required to reduce morbidity.

CASE PRESENTATION

A previously healthy two-year old boy was admitted with history of heavy coughing followed by progressive dyspnea. The chest X-ray showed an extensive opacification of the right lung. Ultrasound studies revealed a large pleural effusion of the right hemithorax. Pleural fluid analysis delivered the unusual diagnosis of chylothorax, most likely induced by preceded excessive coughing. After an unsuccessful treatment attempt with a fat-free diet and continuous pleural drainage for two weeks, therapy with octreotide was initiated. This led to complete and permanent resolution of his pleural effusion within 15 days, without any side effects.

CONCLUSIONS

Severe cough may be a rare cause of chylothorax in young children. Octreotide seems to be an effective and safe treatment of spontaneous or traumatic chylothorax in children. There is, however, a lack of comprehensive studies for chylothorax in children and many issues concerning diagnostic strategies and treatment algorithms remain.

Refractory kaposiform lymphangiomatosis relieved by splenectomy

Introduction

Kaposiform lymphangiomatosis (KLA) is a rare and complex lymphatic anomaly with a poor prognosis. There is no standard treatment, and drug therapies are the most common therapeutic method. However, some patients' symptoms become gradually aggravated despite medical treatment. Splenectomy may be an alternative option when pharmacological therapies are ineffective.

Materials and Methods

We reviewed and evaluated the cases of 3 patients with KLA who ultimately underwent splenectomy. Results: The lesions were diffusely distributed and involved the lungs and spleens of the 3 patients. Laboratory examinations revealed that all three patients had thrombocytopenia and reduced fibrinogen levels. All patients underwent symptomatic splenectomy after the medication failed. Surprisingly, their symptoms greatly improved. Histopathological investigation of the splenic lesions of the three patients confirmed the diagnosis of KLA. Immunohistochemical staining showed positivity for CD31, CD34, podoplanin, Prox-1 and angiopoietin 2 (Ang-2).

Discussion

This study aimed to review the features of KLA patients treated by splenectomy and explore the underlying link between splenectomy and prognosis. The reason for the improvement after splenectomy may be related to increased Ang-2 levels and platelet activation in patients with KLA. Future research should seek to develop more targeted drugs based on molecular findings, which may give new hope for the treatment of KLA.

Investigation into the genetics of fetal congenital lymphatic anomalies

OBJECTIVE

Congenital lymphatic anomalies (LAs) arise due to defects in lymphatic development and often present in utero as pleural effusion, chylothorax, nuchal and soft tissue edema, ascites, or hydrops. Many LAs are caused by single nucleotide variants, which are not detected on routine prenatal testing.

METHODS

Demographic data were compared between two subcohorts, those with clinically significant fetal edema (CSFE) and isolated fetal edema. A targeted variant analysis of LA genes was performed using American College of Medical Genetics criteria on whole exome sequencing (WES) data generated for 71 fetal edema cases who remained undiagnosed after standard workup.

RESULTS

CSFE cases had poor outcomes, including preterm delivery, demise, and maternal preeclampsia. Pathogenic and likely pathogenic variants were identified in 7% (5/71) of cases, including variants in RASopathy genes, RASA1, SOS1, PTPN11, and a novel PIEZO1 variant. Variants of uncertain significance (VOUS) were identified in 45% (32/71) of cases. In CSFEs, VOUS were found in CELSR1, EPHB4, TIE1, PIEZO1, ITGA9, RASopathy genes, SOS1, SOS2, and RAF1.

CONCLUSIONS

WES identified pathogenic and likely pathogenic variants and VOUS in LA genes in 51% of fetal edema cases, supporting WES and expanded hydrops panels in cases of idiopathic fetal hydrops and fluid collections.

Pathogenic variants in PIK3CA are associated with clinical phenotypes of kaposiform lymphangiomatosis, generalized lymphatic anomaly, and central conducting lymphatic anomaly

Complex lymphatic anomalies are debilitating conditions characterized by aberrant development of the lymphatic vasculature (lymphangiogenesis). Diagnosis is typically made by history, examination, radiology, and histologic findings. However, there is significant overlap between conditions, making accurate diagnosis difficult. Recently, genetic analysis has been offered as an additional diagnostic modality. Here, we describe four cases of complex lymphatic anomalies, all with PIK3CA variants but with varying clinical phenotypes. Identification of PIK3CA resulted in transition to a targeted inhibitor, alpelisib. These cases highlight the genetic overlap between phenotypically diverse lymphatic anomalies.

Case report: Generalized lymphatic anomaly of multiple abdominal organs in a young dog

A 9-month-old, female Pomeranian dog presented with vomiting and lethargy. Ultrasonography revealed multilobulated anechoic round shape structures at the ovarian and uterine locations. Through computed tomography scan, an extensive non-contrast multilobulated fluid-filled mass suspected of originating from the walls of the ovary, uterus, urinary bladder and rectum was observed. Ovariohysterectomy and urinary bladder biopsy were performed. Histopathological examination revealed numerous cystic lesions lined by plump cuboidal cells believed to be of epithelial origin. Immunohistochemical staining showed that the cyst-like lesions lining cells were strongly positive for lymphatic vessel endothelial hyaluronan receptor 1. Based on these results, lesions were identified as generalized lymphatic anomaly (GLA), in which lymphangiomas develop in multiple organs. After 6 months follow-up, the size of the cysts remaining in the region of the bladder did not undergo much change. GLA should be included in the differential diagnosis when multiple cystic lesions are interspersed in multiple organs.

Prenatal diagnosis of vascular anomalies

Vascular anomalies are rare disorders that encompass a group of lesions characterized by abnormal development of the lymphovascular system. Majority of these anomalies are present at birth and could potentially be detected during the prenatal period on imaging. This allows for early intervention and prompt management to improve outcomes. However, they can be difficult to diagnose, given the rarity and overlapping findings. In this review article, we provide a comprehensive overview of congenital vascular anomalies with a liberal use of images of recent cases at our center emphasizing prenatal imaging findings and the natural history of these conditions.

Complex Lymphatic Anomalies: Report on a Patient Registry Using the Latest Diagnostic Guidelines

Objective: Generalized lymphatic anomaly (GLA), Gorham-Stout disease (GSD), kaposiform lymphangiomatosis (KLA), and central conducting lymphatic anomaly (CCLA) are rare, multisystem lymphatic disorders, referred to as complex lymphatic anomalies (CLAs). Their etiology remains poorly understood; however, somatic activating mutations have recently been discovered, and the results of targeted treatments are promising. This study aimed to elaborate on the phenotypic description of CLA. Methods: Thirty-six consecutive patients were recruited for the "GLA/GSD Registry" of the University Hospital of Freiburg, Germany (2015-2021). Clinical data were prospectively collected provided that a signed informed consent form was obtained. The latest proposed diagnostic guidelines were retrospectively applied. Results: Thirty-two patients (38% males) were included in the study; 15 GLA, 10 GSD, 3 KLA, and 4 CCLA patients were identified. Eighty-four percent already had symptoms by the age of 15 years. Osteolysis and periosseous soft-tissue infiltration were associated with GSD (p < 0.001 and p = 0.011, respectively), ascites and protein-losing enteropathy with CCLA (p = 0.007 and p = 0.004, respectively), and consumption coagulopathy with KLA (p = 0.006). No statistically significant differences were found in organ involvement, distribution of osteolytic lesions, number of affected bones and fractures. Twenty-five patients had complications; one patient with GLA died despite multimodal treatment. Spontaneous regression was seen in one patient with untreated KLA. Conclusions: CLA are rare, and their overlapping clinical presentations make differential diagnosis difficult. The characterization of our case series contributes to the phenotypic description and differentiation of these four clinical entities. A further understanding of their pathogenesis is crucial for evaluating targeted therapies and optimizing medical care.

Genetics etiologies and genotype phenotype correlations in a cohort of individuals with central conducting lymphatic anomaly

Central conducting lymphatic anomaly (CCLA) is a heterogenous disorder caused by disruption of central lymphatic flow that may result in dilation or leakage of central lymphatic channels. There is also a paucity of known genetic diagnoses associated with CCLA. We hypothesized that specific genetic syndromes would have distinct lymphatic patterns and this would allow us to more precisely define CCLA. As a first step toward "precision lymphology", we defined the genetic conditions associated with CCLA by performing a retrospective cohort study. Individuals receiving care through the Jill and Mark Fishman Center for Lymphatic Disorders at the Children's Hospital of Philadelphia between 2016 and 2019 were included if they had a lymphangiogram and clinical genetic testing performed and consented to a clinical registry. In our cohort of 115 participants, 26% received a molecular diagnosis from standard genetic evaluation. The most common genetic etiologies were germline and mosaic RASopathies, chromosomal abnormalities including Trisomy 21 and 22q11.2 deletion syndrome, and PIEZO1-related lymphatic dysplasia. Next, we analyzed the dynamic contrast magnetic resonance lymphangiograms and found that individuals with germline and mosaic RASopathies, mosaic KRASopathies, PIEZO1-related lymphatic dysplasia, and Trisomy 21 had distinct central lymphatic flow phenotypes. Our research expands the genetic conditions associated with CCLA and genotype-lymphatic phenotype correlations. Future descriptions of CCLA should include both genotype (if known) and phenotype to provide more information about disease (gene-CCLA). This should be considered for updated classifications of CCLA by the International Society of Vascular Anomalies.

Osteopathy in Complex Lymphatic Anomalies

Complex Lymphatic Anomalies (CLA) are lymphatic malformations with idiopathic bone and soft tissue involvement. The extent of the abnormal lymphatic presentation and boney invasion varies between subtypes of CLA. The etiology of these diseases has proven to be extremely elusive due to their rarity and irregular progression. In this review, we compiled literature on each of the four primary CLA subtypes and discuss their clinical presentation, lymphatic invasion, osseous profile, and regulatory pathways associated with abnormal bone loss caused by the lymphatic invasion. We highlight key proliferation and differentiation pathways shared between lymphatics and bone and how these systems may interact with each other to stimulate lymphangiogenesis and cause bone loss.

Lymphatic Anomalies in Children: Update on Imaging Diagnosis, Genetics, and Treatment

Lymphatic anomalies comprise a spectrum of disorders ranging from common localized microcystic and macrocystic lymphatic malformations (LMs) to rare complex lymphatic anomalies, including generalized lymphatic anomaly, Kaposiform lymph-angiomatosis, central conducting lymphatic anomaly, and Gorham-Stout disease. Imaging diagnosis of cystic LMs is generally straightforward, but complex lymphatic anomalies, particularly those with multiorgan involvement or diffuse disease, may be more challenging to diagnose. Complex lymphatic anomalies are rare but associated with high morbidity. Imaging plays an important role in their diagnosis, and radiologists may be the first clinicians to suggest the diagnosis. Furthermore, radiologists are regularly involved in management given the frequent need for image-guided interventions. For these reasons, it is crucial for radiologists to be familiar with the spectrum of entities comprising complex lymphatic anomalies and their typical imaging findings. In this article, we review the imaging findings of lymphatic anomalies, including LMs and complex lymphatic anomalies. We discuss characteristic imaging findings, multimodality imaging techniques used for evaluation, pearls and pitfalls in diagnosis, and potential complications. We also review recently discovered genetic changes underlying lymphatic anomaly development and the advent of new molecularly targeted therapies.

Lymphatic Phenotype of Noonan Syndrome: Innovative Diagnosis and Possible Implications for Therapy

Dysregulation of the Ras/Mitogen-activated protein kinase (MAPK) signaling pathway is suggested to play a pivotal role in the development of the lymphatic system in patients with Noonan Syndrome (NS). Pathogenic gene variants in the Ras/MAPK pathway can therefore lead to various lymphatic diseases such as lymphedema, chylo-thorax and protein losing enteropathy. Diagnosis and treatment of the lymphatic phenotype in patients with NS remain difficult due to the variability of clinical presentation, severity and, probably, underlying unknown pathophysiologic mechanism. The objective of this article is to give an overview of the clinical presentation of lymphatic disease in relation to central conducting lymphatic anomalies (CCLA) in NS, including new diagnostic and therapeutic options. We visualized the central conducting lymphatic system using heavily T2-weighted MR imaging (T2 imaging) and Dynamic Contrast-enhanced MR Lymphangiography (DCMRL) and compared these results with the lymphatic clinical presentation in seven patients with NS. Our results show that most patients with NS and lymphatic disease have CCLA. Therefore, it is probable that CCLA is present in all patient with NS, presenting merely with lymphedema, or without sensing lymphatic symptoms at all. T2 imaging and DCMRL can be indicated when CCLA is suspected and this can help to adjust therapeutic interventions.