Clinical Features and Prognosis of Generalized Lymphatic Anomaly, Kaposiform Lymphangiomatosis, and Gorham-Stout Disease

Clinical approach for pulmonary lymphatic disorders

In this editorial, we discuss the clinical implications of the article "Lymphatic plastic bronchitis and primary chylothorax: A study based on computed tomography lymphangiography" published by Li et al. Pulmonary lymphatic disorders involve abnormalities in the lymphatic tissues within the thoracic cavity. Specifically, pulmonary lymphatic perfusion syndrome describes a condition where the flow of lymphatic fluid in the lungs is redirected towards abnormally widened lymphatic vessels. Clinically, individuals with this syndrome may experience symptoms such as chyloptysis, plastic bronchitis (PB), chylothorax, chylopericardium, and interstitial lung disease. These disorders can be caused by various factors, including PB, chylothorax, and complex lymphatic malformations. Advancements in lymphatic imaging techniques, such as intranodal lymphangiography, computed tomography lymphangiography, and dynamic contrast-enhanced magnetic resonance lymphangiography, have enabled the detection of abnormal lymphatic flow. This has enhanced our understanding of the pathophysiology of these conditions. Additionally, innovative minimally invasive treatments, such as thoracic duct embolization, selective embolization of lymphatic channels, and surgical procedures aim to improve clinical condition of patients and address their dietary needs.

Pericardial fenestration and thoracic duct ligation for treatment of chylopericardium as first symptom of underlying generalized lymphatic anomaly: a case report

INTRODUCTION

Chylopericardium represents a rare condition of chyle accumulation within the pericardial sac, caused by abnormal thoracic duct anatomy or prolonged increased pressure. Nothing by mouth (NPO) policy and total parenteral nutrition (TPN), even in combination with pericardial drainage, render only a temporary solution. Surgical intervention with thoracic duct ligation and creation of a pericardial window is believed to be the most effective treatment.

CASE PRESENTATION

An 18-year-old male was referred with a persisting idiopathic chylopericardium for five months. Various drainages and conservative treatment failed. To more permanently treat the chylopericardium, we created a pericardial window and ligated the thoracic duct by right-sided uniportal video-assisted thoracoscopic surgery. Postoperative NPO and TPN for 1 week were initiated, followed by medium-chain-triglycerides diet for 1 week. Clinical improvement occurred and the chest drain was removed two weeks after surgery. Magnetic resonance imaging of the whole body showed multiple cystic lesions in spleen and skeleton compatible with generalized lymphatic anomaly (GLA), proven by the anatomopathological examination of the thoracic duct and lung biopsy. Sirolimus was initiated for further treatment.

CONCLUSION

In this case of idiopathic chylopericardium, we successfully performed thoracoscopic thoracic duct ligation and creation of a pericardial window, diagnosing a GLA.

Pediatric cerebrospinal fluid rhinorrhea caused by low flow vascular anomaly of the temporal bone: A case series

OBJECTIVE

Atraumatic cerebrospinal fluid (CSF) rhinorrhea is uncommon in children and necessitates a multi-disciplinary evaluation for an etiology. Underlying osseous abnormality due to extensive or multifocal low flow vascular anomaly should be considered as a potential cause of spontaneous CSF leak. Treatment of multifocal low flow vascular anomalies may include medical and surgical approaches. In this series, we seek to determine the presenting signs and symptoms and medical and surgical treatment options for multifocal or extensive low flow vascular anomalies.

METHODS

A retrospective case series at a quaternary care children's hospital was compiled. All children with CSF rhinorrhea diagnosed and treated for multifocal low flow vascular anomalies at our institution were included. A total of four patients were identified.

RESULTS

All four patients had delay in initial diagnosis of underlying cause of meningitis and CSF rhinorrhea. Average age at diagnosis of multifocal low flow vascular anomaly was 7 years. This was on average 4 years after initial presentation for medical attention. Treatment approach was multidisciplinary and included medical management with sirolimus and bisphosphonates as well as surgical approaches to the skull base (lateral and anterior) to prevent CSF egress.

CONCLUSION

Consideration of multifocal low flow vascular anomaly should be included in any pediatric patient presenting with CSF rhinorrhea.

Changes in cell morphology and function induced by the NRAS Q61R mutation in lymphatic endothelial cells

Recently, a low-level somatic mutation in the NRAS gene (c.182 A > G, Q61R) was identified in various specimens from patients with kaposiform lymphangiomatosis. However, it is unknown how these low-frequency mutated cells can affect the characterization and surrounding environment of their lesions. To understand the pathogenesis and association of these gene abnormalities, we established NRASQ61R mutated lymphatic endothelial cells transfected with lentivirus vector and undertook morphological and functional characterization, protein expression profiling, and metabolome analysis. NRASQ61R human dermal lymphatic endothelial cells showed poor tube formation, a low proliferation rate, and high migration ability, with an increase in the ratio of mutated cells. An analysis of signaling pathways showed inactivation of the PIK3/AKT/mTOR pathway and hyperactivation of the RAS/MAPK/ERK pathway, which was improved by MAPK kinase (MEK) inhibitor treatment. This study shows the theoretical circumstances induced in vitro by NRASQ61R-mutated cells in the affected lesions of kaposiform lymphangiomatosis patients.

Targeted treatment in complex lymphatic anomaly: a case of synergistic efficacy of trametinib and sirolimus

Repurposing anticancer drugs to vascular malformations has significantly improved patient outcomes. Complex Lymphatic Anomalies (CLA) are part of the spectrum of lymphatic malformations (LMs) that share similar oncogenic mutations to cancer. We report the case of a young patient with highly symptomatic CLA who was initially treated with sirolimus, due to the frequent involvement of the PI3K-AKT-mTOR pathway in CLA pathogenesis. Despite an initial reduction in symptoms, sirolimus progressively lost its effectiveness. After an unsuccessful attempt with trametinib alone, sirolimus was added to trametinib and resulted in a significant, rapid and sustained improvement in symptoms. This suggests that, contrary to current dogmas, combination therapy using sub-therapeutic doses targeting both the PI3K and RAS pathways retains efficacy without generating the toxicity known for combination therapies, and is beneficial in the management of CLAs and potentially other vascular anomalies.

How we use angiopoietin-2 in the diagnosis and management of vascular anomalies

The diagnosis of vascular anomalies remains challenging due to significant clinical heterogeneity and uncertain etiology. Evaluation using biopsy and/or genetic testing for somatic variants is invasive, expensive, and prone to sampling error. There is great need for noninvasive and easily measured blood laboratory biomarkers that can aid not only in diagnosis, but also management of treatments for vascular anomalies. Angiopoietin-2, a circulating blood angiogenic factor, is highly elevated in patients with kaposiform hemangioendothelioma with Kasabach-Merritt phenomenon and kaposiform lymphangiomatosis. Here, we describe our clinical experience using serum angiopoietin-2 as a biomarker for diagnosis and monitoring response to treatment.

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.

Abnormalities in C-type lectin-like receptor 2 in a patient with Gorham-Stout disease: the first case report

Background

Gorham-Stout disease (GSD) is a form of lymphangiomatosis of unknown etiology, characterized by abnormal distribution of lymphatic vessels. Platelets and lymphangiogenesis are closely related via C-type lectin-like receptor 2 (CLEC-2)/podoplanin.

Key Clinical Question

Despite similarities between abnormal lymphatic vessels in CLEC-2-deficient mice and patients with GSD, whether CLEC-2 on platelets is involved in GSD pathogenesis is unknown.

Clinical Approach

We examined CLEC-2 expression in platelets of a patient with lethal GSD. Most of the patient's platelets expressed aberrant CLEC-2 that was not detectable by certain monoclonal antibodies for human CLEC-2. Further, this population was not activated by a CLEC-2-activating snake venom, rhodocytin. Possible causes of abnormal CLEC-2 including anti-CLEC-2 autoantibodies, podoplanin binding to CLEC-2, and pathogenic CLEC1B gene alteration were excluded.

Conclusions

We believe that this is the first report of a patient with structurally and functionally abnormal CLEC-2. CLEC-2 abnormality may be associated with dysregulated lymphangiogenesis in GSD.

Generalized cystic lymphangiomatosis incidentally diagnosed in an asymptomatic adult: Imaging findings of a very rare case

Lymphangiomas are benign lesions of vascular origin with lymphatic differentiation, most commonly found in the head and neck. Generalized lymphangiomatosis is a very rare condition in adults, which is characterized by a diffuse proliferation of lymphatic vessels. The lymphangioma is composed of lymphatic endothelium-lined cystic spaces. This condition can be histologically differentiated from other vascular disorders such as cavernous or capillary hemangioma. However, many cases of lymphangioma can be confused with other vascular disorders, because of overlapping histologic findings. radiologic examinations, such as CT scan and MR imaging, are useful for assessing the morphologic feature and also the extent of disease, it is important to know the radiologic findings of generalized lymphangiomatosis. In this paper, we report a case of generalized lymphangiomatosis in a 42-year-old male who presented with left flank pain and hematuria. The first differential diagnosis was renal colic; hence he underwent an abdominopelvic computed tomography scan (CT scan). In the performed CT scan multiple cystic lesions were seen in the liver and spleen. Also, lytic lesions were seen in bones. CT-guided biopsy was performed and the result was compatible with generalized lymphangiomatosis, confirmed by cytology. Generalized lymphangiomatosis is a rarely reported disease in children and young adults. Delayed diagnosis in older patients or misdiagnosis is common due to its rarity and nonspecific clinical presentation. Different imaging modalities can incidentally diagnose the disease in asymptomatic patients. So radiologists should be aware of the disease manifestations in imaging modalities to diagnose the disease sooner and help the clinician start the therapy if needed.

Pediatric Ribs at Chest Radiography: Normal Variants and Abnormalities

Normal variants and abnormalities of the ribs are frequently encountered on chest radiographs. Accurate identification of normal variants is crucial to avoid unnecessary investigations. A meticulous evaluation of rib abnormalities can provide valuable insights into the patient's symptoms, and even when no osseous condition is suspected, rib abnormalities may offer critical clues to underlying conditions. Rib abnormalities are associated with various conditions, including benign tumors, malignant tumors, infectious and inflammatory conditions, vascular abnormalities, metabolic disorders, nonaccidental injuries, malformation syndromes, and bone dysplasias. Abnormalities of the ribs are classified into three groups based on their radiographic patterns: focal, multifocal, and diffuse changes. Focal lesions are further subdivided into nonaggressive lesions, aggressive lesions, and infectious and inflammatory disorders. Radiologists should be aware of individual disorders of the pediatric ribs, including their imaging findings, relevant clinical information, and underlying pathogenesis. Differential diagnoses are addressed as appropriate. Since chest radiographs can suffice for diagnosis in certain cases, the authors emphasize a pattern recognition approach to radiographic interpretation. However, additional cross-sectional imaging may be necessary for focal lesions such as tumors or inflammatory conditions. Awareness of disease-specific imaging findings helps ascertain the nature of the lesion and directs appropriate management. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Consequences of Aging on Bone

With the aging of the global population, the incidence of musculoskeletal diseases has been increasing, seriously affecting people's health. As people age, the microenvironment within skeleton favors bone resorption and inhibits bone formation, accompanied by bone marrow fat accumulation and multiple cellular senescence. Specifically, skeletal stem/stromal cells (SSCs) during aging tend to undergo adipogenesis rather than osteogenesis. Meanwhile, osteoblasts, as well as osteocytes, showed increased apoptosis, decreased quantity, and multiple functional limitations including impaired mechanical sensing, intercellular modulation, and exosome secretion. Also, the bone resorption function of macrophage-lineage cells (including osteoclasts and preosteoclasts) was significantly enhanced, as well as impaired vascularization and innervation. In this study, we systematically reviewed the effect of aging on bone and the within microenvironment (including skeletal cells as well as their intracellular structure variations, vascular structures, innervation, marrow fat distribution, and lymphatic system) caused by aging, and mechanisms of osteoimmune regulation of the bone environment in the aging state, and the causal relationship with multiple musculoskeletal diseases in addition with their potential therapeutic strategy.

Generalized lymphatic anomaly in adult patients: An eminently radiological diagnosis

Generalized lymphatic anomaly (GLA) is an uncommon congenital disease secondary to the proliferation of lymphatic vessels in any organ except the central nervous system. GLA has a wide spectrum of clinical and radiological presentations, among which osteolytic lesions are the most widespread, being the ribs the most commonly affected bone. GLA is diagnosed mainly in children and young adults; nevertheless, on rare occasions it can remain asymptomatic and be detected incidentally in older patients. We present an unusual case of GLA in an asymptomatic 54-year-old man who had atypically distributed, purely cystic bone lesions on CT; measuring the Hounsfield (HU) of these lesions enabled us to suspect GLA. This suspicion was confirmed with MRI, PET/CT, CT-guided fine-needle aspiration biopsy, and fluoroscopy-guided percutaneous vertebral biopsy. After surgical resection of one of the lesions, histologic study provided the definitive diagnosis.

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.

Back to the Future II-A Comprehensive Update on the Rapidly Evolving Field of Lymphatic Imaging and Interventions

ABSTRACT

Lymphatic imaging and interventional therapies of disorders affecting the lymphatic vascular system have evolved rapidly in recent years. Although x-ray lymphangiography had been all but replaced by the advent of cross-sectional imaging and the scientific focus shifted to lymph node imaging (eg, for detection of metastatic disease), interest in lymph vessel imaging was rekindled by the introduction of lymphatic interventional treatments in the late 1990s. Although x-ray lymphangiography is still the mainstay imaging technique to guide interventional procedures, several other, often less invasive, techniques have been developed more recently to evaluate the lymphatic vascular system and associated pathologies. Especially the introduction of magnetic resonance, and even more recently computed tomography, lymphangiography with water-soluble iodinated contrast agent has furthered our understanding of complex pathophysiological backgrounds of lymphatic diseases. This has led to an improvement of treatment approaches, especially of nontraumatic disorders caused by lymphatic flow abnormalities including plastic bronchitis, protein-losing enteropathy, and nontraumatic chylolymphatic leakages. The therapeutic armamentarium has also constantly grown and diversified in recent years with the introduction of more complex catheter-based and interstitial embolization techniques, lymph vessel stenting, lymphovenous anastomoses, as well as (targeted) medical treatment options. The aim of this article is to review the relevant spectrum of lymphatic disorders with currently available radiological imaging and interventional techniques, as well as the application of these methods in specific, individual clinical situations.

Kaposiform lymphangiomatosis: Diagnosis, pathogenesis, and treatment

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

The lymphatic vasculature in lung function and respiratory disease

The lymphatic vasculature maintains tissue homeostasis via fluid drainage in the form of lymph and immune surveillance due to migration of leukocytes through the lymphatics to the draining lymph nodes. Lymphatic endothelial cells (LECs) form the lymphatic vessels and lymph node sinuses and are key players in shaping immune responses and tolerance. In the healthy lung, the vast majority of lymphatic vessels are found along the bronchovascular structures, in the interlobular septa, and in the subpleural space. Previous studies in both mice and humans have shown that the lymphatics are necessary for lung function from the neonatal period through adulthood. Furthermore, changes in the lymphatic vasculature are observed in nearly all respiratory diseases in which they have been analyzed. Recent work has pointed to a causative role for lymphatic dysfunction in the initiation and progression of lung disease, indicating that these vessels may be active players in pathologic processes in the lung. However, the mechanisms by which defects in lung lymphatic function are pathogenic are understudied, leaving many unanswered questions. A more comprehensive understanding of the mechanistic role of morphological, functional, and molecular changes in the lung lymphatic endothelium in respiratory diseases is a promising area of research that is likely to lead to novel therapeutic targets. In this review, we will discuss our current knowledge of the structure and function of the lung lymphatics and the role of these vessels in lung homeostasis and respiratory disease.

Case 311: Generalized Lymphatic Anomaly

HISTORY

A 14-year-old boy presented with asthenia, low back pain, and abdominal distention. The onset of symptoms was slow and progressive over a few months. The patient had no contributing past medical history. At physical examination, all vital signs were normal. Only pallor and positive fluid wave test results were noted; there was no lower limb edema, mucocutaneous lesions, or palpable lymph node enlargement. Laboratory work-up revealed a decreased hemoglobin concentration of 9.3 g/dL (normal range, 12-16 g/dL) and a decreased hematocrit level of 29.8% (normal range, 37%-45%), but all other laboratory values were normal. Contrast-enhanced CT of the chest, abdomen, and pelvis was performed.

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.

French national diagnosis and care protocol (PNDS, protocole national de diagnostic et de soins): cystic lymphatic malformations

Cystic lymphatic malformations (LMs) are rare chronic conditions which management differs according to the type (macrocystic LMs, microcystic LMs or both). Studies are lacking due to rarity of the pathology. We aimed to establish a French National Diagnosis and Care Protocol (PNDS: Protocole National de Diagnostic et de Soins), to provide health professionals with free open access synthesis on optimal management and care of patients with LMs ( https://www.has-sante.fr/upload/docs/application/pdf/2021-03/malformations_lymphatiques_kystiques_-_pnds.pdf ). The process included a critical review of the literature and multidisciplinary expert consensus. LMs are congenital but are not always discovered at birth. Nearly 75% of them are located in the head and neck because of the highly dense lymphatic system in this region. Physical examination (showing painless masses with normal skin color and depressible consistency, or cutaneous/mucosal lymphangiectasia) and color Doppler ultrasonography, usually allow for diagnosis. MRI (involving T2 sequences with fat saturation in at least two spatial planes) is the tool of choice for evaluating anatomical extension, characterizing lesions (microcystic and macrocystic), and before considering therapeutic management. A biopsy, coupled to a blood sample, can also be used for molecular biology analyses, to search for activating mutations of the PIK3CA gene, particularly with LM integrating in a syndromic form (CLOVES or Klippel-Trenaunay syndrome) but also in certain isolated (or common) LMs. The spontaneous evolution of LMs, in particular microcystic forms, is often toward progressive aggravation, with an increase in the number of vesicles, thickening, increased oozing and bleeding, while pure macrocystic LMs may regress due to "natural sclerosis", i.e. fibrosis secondary to an inflammatory reorganization after common infantile infections. In case of voluminous LMs or syndromic forms, functional and psychological repercussions can be major, deteriorating the patient's quality of life. LMs must be treated by physicians integrated in multidisciplinary teams, and be personalized. Management is a life-long process that involves one or several of these therapies: conservative management, physical therapy (compression), sclerotherapy, surgery, drugs such as mTOR inhibitors (sirolimus), that has shown efficacy in decreasing the volume of LMs, and, more recently, PI3K-inhibitors in syndromic forms. Psychological and social support is necessary, taking into account the patient and his family.

Generalized Lymphatic Anomaly as a Differential Diagnosis of Lytic Lesions

Generalized lymphatic anomaly (GLA) is an infrequent multiorgan disease characterized by the presence of abnormal proliferation of lymphatic vessels. The diagnosis requires histological confirmation, and the treatment is controversial. We are presenting a case of a 28-year-old male patient who was diagnosed with an extragonadal mediastinal nonseminomatous germ cell tumor. He underwent chemotherapy, and during this treatment, radiologic findings evidenced lytic lesions. Multiple biopsies were performed, which revealed the presence of abnormal lymphatic vessels, characteristic of GLA. There are different etiologies of osteolytic lesions, and on some occasions, they mimic a tumoral entity. The clinical suspicion of GLA is the first step in approaching the diagnosis, particularly in young adult patients.

Endoscopic Endonasal Dural Reconstruction for a Cerebrospinal Fluid Leak in the Middle Cranial Fossa of a Patient with Gorham-stout Disease with Skull Base Defect

We report the use of endoscopic endonasal surgery for dural reconstruction following a cerebrospinal fluid leak in a 33-year-old patient with recurrent meningitis since at age of 2 years. Magnetic resonance imaging showed osteolytic changes in the left temporal and sphenoid bones, including the left pterygoid plate, a few left temporal encephaloceles, and cerebrospinal fluid-like fluid in the expanded Meckel's cave and the parapharyngeal space. After endoscopic endonasal surgery, Gorham-Stout disease was diagnosed. No recurrence of cerebrospinal fluid leakage or meningitis has been observed. Thus, endoscopic endonasal surgery might improve clinical outcomes in patients with Gorham-Stout disease and skull base defects.

Recurrent haemoptysis: a rare diagnosis of kaposiform lymphangiomatosis and review of literature

Kaposiform lymphangiomatosis (KLA) is a rare clinicopathological entity among lymphatic anomalies. The main involved sites are the mediastinum and the lungs but the disease can also affect multiple extrathoracic organs. Little is known about the pathophysiology, the natural history, the treatment response and the long-term outcome of this disorder. KLA is typically diagnosed in childhood. We present here the case of an adult man with 13 years recurrent episodes of haemoptysis who was finally found to suffer from KLA. Following this, we present a comprehensive review of the literature.

How we approach the diagnosis and management of complex lymphatic anomalies

Complex lymphatic anomalies (CLA) are congenital diseases of the lymphatic circulation system that are associated with significant morbidity and early mortality. While guidelines for the comprehensive evaluation of the CLA were recently published, the diagnostic approach and medical management are not standardized. This article presents the clinical features of four CLA: Gorham-Stout disease, generalized lymphatic anomaly, kaposiform lymphangiomatosis, and central collecting lymphatic anomaly. We also offer three cases from the authors' practice and our views on diagnostic testing and disease management including supportive care, medical therapies, and other interventions.

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.

Gorham-Stout disease of skull base leading to cranial settling and rhinorrhea: a case-based review

PURPOSE

Gorham-Stout disease (GSD) is a rare progressive osteolytic disorder, theoretically caused by lymphovascular endothelial proliferation. Spinal involvement carries a dismal prognosis because of neurological consequences. Lesions of the skull base are extremely rare and entail even more devastating prognosis due to cervical instability and cerebrospinal fluid (CSF) leakage. Due to scarcity of this condition, the aim of this study was to give an overview of skull base GSD and review the cases with such condition reported in the literature.

METHODS

In this case-based review, different aspects of skull base GSD are discussed, and a sample clinical case of GSD leading to cranial settling and rhinorrhea is presented. The characteristics, symptoms, and managements of all English-language PubMed-reported cases were reviewed, and different features of presentation and methods of treatments were analyzed.

RESULTS

Based on the literature review, most of the cases encountered serious problems in the course of the disease. Meningitis/CSF leakage was detected in 12 of 26 collected cases, followed by hearing loss/tinnitus/otitis media in 10 cases, headache in 8, and neck pain/stiffness in 8 patients. Despite a variety of treatments, improvement was only observed in 8 of 26 collected cases. The reminders showed either stable condition or worsening and death.

CONCLUSION

All cases of GSD of the skull base should be evaluated for rhinorrhea/otorrhea and cranial settling, both of them being among the most life-threatening conditions. Since definite treatment, in order to stop disease progression, is sometimes impossible, symptomatic and supportive treatment should be started as possible.

Understanding Lymphatic Anatomy and Abnormalities at Imaging

Lymphatic abnormalities encompass a wide range of disorders spanning solitary common cystic lymphatic malformations (LMs) to entities involving multiple organ systems such as lymphangioleiomyomatosis. Many of these disorders are rare, yet some, such as secondary lymphedema from the treatment of malignancy (radiation therapy and/or lymph node dissection), affect millions of patients worldwide. Owing to complex and variable anatomy, the lymphatics are not as well understood as other organ systems. Further complicating this is the variability in the description of lymphatic disease processes and their nomenclature in the medical literature. In recent years, medical imaging has begun to facilitate a deeper understanding of the physiology and pathologic processes that involve the lymphatic system. Radiology is playing an important and growing role in the diagnosis and treatment of many lymphatic conditions. The authors describe both normal and common variant lymphatic anatomy. Various imaging modalities including nuclear medicine lymphoscintigraphy, conventional lymphangiography, and MR lymphangiography used in the diagnosis and treatment of lymphatic disorders are highlighted. The authors discuss imaging many of the common and uncommon lymphatic disorders, including primary LMs described by the International Society for the Study of Vascular Anomalies 2018 classification system (microcystic, mixed, and macrocystic LMs; primary lymphedema). Secondary central lymphatic disorders are also detailed, including secondary lymphedema and chylous leaks, as well as lymphatic disorders not otherwise easily classified. The authors aim to provide the reader with an overview of the anatomy, pathology, imaging findings, and treatment of a wide variety of lymphatic conditions. ^©RSNA, 2022.

Kaposiform lymphangiomatosis presenting with a Group A Streptococcus pericardial effusion

A 4-year-old child was transferred to the paediatric intensive care unit with acute respiratory failure following 4 days of fever, nausea and vomiting. Chest X-ray on admission had an enlarged cardiac silhouette and transthoracic echo confirmed a large pericardial effusion. An emergent pericardiocentesis was performed at bedside which drained nearly 1000 mL of purulent fluid. Postdrainage course was complicated by acute systolic and diastolic heart failure, thrombocytopenia and acute renal failure. A chest CT and MRI were concerning for a diffuse mediastinal soft-tissue density, so the patient underwent interventional radiology-guided biopsy complicated by haemorrhage requiring mediastinal exploration and subtotal thymectomy. Histopathology revealed changes consistent with kaposiform lymphangiomatosis and MRI demonstrated involvement of the lumbar spine and right hip. Following a course of intravenous antibiotics, the patient was started on sirolimus and prednisolone and ultimately discharged home.

Neonatal Generalized Lymphatic Anomaly with Skin Involvement

Generalized lymphatic anomaly (GLA) is a rare congenital disorder of lymphatic development, presenting with multiple lymphatic malformations in different organs and tissues. Here, we present a case of a female neonate prenatally diagnosed with foetal hydrops and a mediastinal cystic lymphatic malformation that showed postnatal expansive and infiltrative growth into the major airways, compromising mechanical ventilation and further management of the neonate. Complications that arose during surgical treatment of mediastinal structures led to the patient’s death. Lymphatic malformations were also noted in the skin at birth. Furthermore, a skin biopsy performed immediately after birth and the autopsy revealed an extremely rare diagnosis of combined macrocystic and microcystic forms of GLA with skin involvement.

Non-Traumatic Chylothorax and Chylopericardium: Diagnosis and Treatment Using an Algorithmic Approach Based on Novel Lymphatic Imaging

RATIONALE

Outcomes of interventional lymphangiographic treatment of nontraumatic chylous pleural effusions using traditional approaches have been highly variable. Recent advances in lymphatic imaging have revealed variations in underlying pathophysiology enabling improved targeting of therapeutic interventions.

OBJECTIVE

To assess outcomes of an algorithm for management of nontraumatic chylous pleural effusions based on advanced MR identification of various abnormalities in the thoracoabdominal lymphatic network that give rise to chylothorax.

METHODS

Novel lymphatic MR imaging was performed in 52 patients ages 11 to 89 years. Three distinct pathophysiological patterns were found: (1) abnormal pulmonary lymphatic flow from the thoracic duct only; (2) abnormal pulmonary lymphatic flow from retroperitoneal lymphatic networks with or without involvement of the thoracic duct; and (3) chylous ascites presenting as chylous pleural effusion. Lymphatic interventions were individualized to the underlying pathophysiological patterns.

RESULTS

In 41/52 (79%) patients, imaging revealed abnormal pulmonary lymphatic flow from the thoracic duct and/or retroperitoneal lymphatic networks. Thoracic duct embolization and/or interstitial embolization of retroperitoneal lymphatic resulted in resolution of chylothorax in this group in 38/41 (93%) of those patients. Five patients experienced Grade 1 or 2 complications. One patient succumbed to post-operative stress-induced cardiomyopathy and pulmonary embolism. Chylous ascites was the cause of chylothorax in 11/52 (21%) patients. Eight chose to undergo interventions for chylous ascites with clinical success in 6/8 (75%).

CONCLUSIONS

Application of MRI-guided intervention algorithm resulted in successful control of non-traumatic chylothorax in 93% patients with abnormal pulmonary lymphatic flow. Appropriate treatment of chylous ascites presenting as a pleural effusion requires systematic evaluation and diagnosis prior to potential treatments.

Cutaneous Vascular Neoplasms of Uncertain Biological Behavior

Neoplasms of uncertain biological behavior present physicians with a genuine conundrum in practice. Cutaneous vascular neoplasms within this category are exceedingly rare, possessing significant gaps and uncertainty in many facets of clinical practice. Firstly, lesions were selected for review based on their categorization as indeterminate behavior, indicating the potential for local recurrence and rarely metastasize. After identification of the target lesions, a comprehensive review of the literature using national databases produced several landmark studies and case series regarding these neoplasms. Limiting the review to only cutaneous limited tumors narrowed the pool of studies; however, quite a large sum of papers remained. Examination of each paper yielded beneficial results on diagnosing, effective treatments, follow-up findings, and prognosis for each indeterminate lesion discussed. Overall, the literature search combined the molecular, histologic, immunohistochemical, surgical strategies to develop an up-to-date and comprehensive framework to guide physicians when encountering such lesions. The tumors reviewed include: kaposiform hemangioendothelioma, endovascular papillary angioendothelioma, pseudomyogenic hemangioendothelioma, retiform hemangioendothelioma, epithelioid hemangioendothelioma, and composite hemangioendothelioma.

Characterization of kaposiform lymphangiomatosis tissue-derived cells

BACKGROUND

Kaposiform lymphangiomatosis (KLA) is a recently characterized systemic lymphatic anomaly. Activation of RAS/MAPK and PI3K/AKT/mTOR pathways may affect KLA pathogenesis, but the cellular basis of KLA is unclear. Abnormal-spindle endothelial cells that express lymphatic endothelial cell (LEC) markers are characteristic of KLA histopathology. This study evaluated patient-derived KLA cells to establish their morphological and biological characteristics.

PROCEDURE

We established cell lines from primary KLA tissues of two patients with KLA and examined their morphological and functional characteristics, messenger RNA and protein expression profiles, gene mutations, and responses to inhibitors of the RAS/MAPK and PI3K/AKT/mTOR pathways.

RESULTS

Both KLA cell lines showed spindle-shaped morphology, stained positive for podoplanin (PDPN), and exhibited impaired tube-formation properties. They expressed LEC marker PDPN and mesenchymal stem cell markers (CD90, CD105) in the absence of endothelial cell markers (CD34, CD31, VWF), per real-time polymerase chain reaction. Both mTOR inhibitor rapamycin and MEK inhibitor trametinib inhibited growth of the two cell lines. A NRAS p.Q61R variant was found in one of two independent KLA tissue samples, but not in the KLA cells (per targeted next-generation sequencing); and KLA cells with this variant had elevated AKT phosphorylation levels. ERK phosphorylation levels were undetectable in both KLA cell lines.

CONCLUSIONS

Inhibition of the RAS/MAPK and PI3K/AKT/mTOR pathways may represent potential therapeutic targets in KLA. These patient-derived KLA cell lines will be useful research tools to elucidate KLA etiology, and could pave the way for basic, translational, and preclinical studies of this disease.

CT and MRI Findings of Focal Splenic Lesions and Ascites in Generalized Lymphatic Anomaly, Kaposiform Lymphangiomatosis, and Gorham-Stout Disease

Objectives:

This study aimed to evaluate the CT and MRI findings of focal splenic lesions and ascites in generalized lymphatic anomaly (GLA), kaposiform lymphangiomatosis (KLA), and Gorham-Stout disease (GSD).

Material and Methods:

Twenty-three patients (10 with GLA, 5 with KLA, and 8 with GSD) who underwent abdominal CT and/or MRI before treatment were included in this study, and their imaging findings were retrospectively evaluated.

Results:

Focal splenic lesions were observed in nine patients; these lesions were observed frequently in GLA (n = 5; 50%) or KLA (n = 3; 60%) compared with GSD (n = 1; 13%); however, no significant differences were found between the three groups (P = 0.190). On CT images among eight patients (4 with GLA, 3 with KLA, and 1 with GSD) with focal splenic lesions who underwent CT, the number of focal splenic lesions per patient ranged from 2 to 189 (mean, 42) and the maximum diameter of focal splenic lesions ranged from 2 to 39 mm (mean, 8 mm), while more than 30 focal splenic lesions per patient were observed in 2 (50%) GLA and focal splenic lesions with maximum diameters of ≥10 mm were observed in 4 (100%) GLA but not in KLA or GSD. Ascites was observed in five patients; significant differences were observed among KLA (n = 4; 80%), GLA (n = 1; 10%), and GSD (n = 0; 0%) (P < 0.01). Ascites was significantly more frequent in KLA than in GSD (P < 0.05).

Conclusion:

More than 30 focal splenic lesions per patient and/or focal splenic lesions with maximum diameters of ≥10 mm were observed only in GLA. Focal splenic lesions tended to be less frequent in GSD, whereas ascites tended to be frequent in KLA.

A Case of Gorham-Stout Disease Treated with Fistula Closure by Transmeatal Approach

Gorham-Stout disease, a rare and intractable disease of unknown etiology, causes systemic bone lysis and replacement with lymphoid tissue. Here, we report a case of Gorham-Stout disease with cerebrospinal fluid leakage in a 16-year-old boy. The patient complained of nasal discharge, right ear obstruction, fever, and headache. A computed tomography scan of the head showed osteolysis around the right internal carotid artery, vestibule, and cochlea and osteolytic changes in the left parietal bone. It was suggested that the patient had bacterial meningitis owing to the leakage of cerebrospinal fluid from the fistula caused by the temporal bone osteolysis. He was treated with meropenem, and a transmeatal fistula closure and a bone biopsy of the left parietal bone were performed. Intraoperatively, osteolysis was observed on the promontory and around the internal carotid artery. The fistula was closed by dense filling and compression around the fistula, in the middle ear cavity, and in the external auditory canal. The symptoms disappeared after the surgery. Bone biopsy showed the presence of a lymphangioma, and Gorham-Stout disease was diagnosed. Prophylactic bisphosphonate therapy was initiated. A 4-year follow-up revealed no progression of the disease.

Multidisciplinary Multiagent Treatment of Complex Lymphatic Anomalies with Severe Bone Disease: A Single-Site Experience

Background: Complex lymphatic anomalies (CLA) are a group of conditions that pose diagnostic and therapeutic challenges due to their rarity and overlapping clinical findings. This case series describes the complex pathology and novel combination therapies of three patients diagnosed with various types of CLA. Methods and Results: A retrospective review of medical records was performed for three patients treated for CLA between 2011 and 2019. Diagnostics, imaging, treatment, and follow-up were reviewed in the electronic medical record and combined with the literature review within the analysis. One patient had involvement of her skull base and ear canals, diagnosed after ear canal abnormalities were detected on computed tomography following meningitis. The second patient had involvement of her posterior ribs and T7-T12 vertebral bodies, with thoracic instability requiring a back brace. The third patient had involvement of his left lower extremity and hemipelvis, necessitating a left above the knee amputation. Case 1 progressed on sirolimus and pamidronate but responded to zoledronic acid (ZA). She developed flares of coagulopathy and cellulitis that required reinforcement with vincristine and steroid pulses. Similarly, case 2 progressed on sirolimus and ZA alone, but achieved stable disease with added vincristine. Upon further disease progression, stabilization was obtained by the reinforcement of ZA. Case 3 required a combination of surgery as well as medical management with sirolimus and pamidronate. All three patients now have stable disease. Conclusion: This case series depicts a multidisciplinary and multiagent approach to the management of CLA with severe bony involvement using sirolimus, bisphosphonates, vincristine, and steroids.

KRAS-driven model of Gorham-Stout disease effectively treated with trametinib

Gorham-Stout disease (GSD) is a sporadically occurring lymphatic disorder. Patients with GSD develop ectopic lymphatics in bone, gradually lose bone, and can have life-threatening complications, such as chylothorax. The etiology of GSD is poorly understood, and current treatments for this disease are inadequate for most patients. To explore the pathogenesis of GSD, we performed targeted high-throughput sequencing with samples from a patient with GSD and identified an activating somatic mutation in KRAS (p.G12V). To characterize the effect of hyperactive KRAS signaling on lymphatic development, we expressed an active form of KRAS (p.G12D) in murine lymphatics (iLEC^Kras mice). We found that iLEC^Kras mice developed lymphatics in bone, which is a hallmark of GSD. We also found that lymphatic valve development and maintenance was altered in iLEC^Kras mice. Because most iLEC^Kras mice developed chylothorax and died before they had significant bone disease, we analyzed the effect of trametinib (an FDA-approved MEK1/2 inhibitor) on lymphatic valve regression in iLEC^Kras mice. Notably, we found that trametinib suppressed this phenotype in iLEC^Kras mice. Together, our results demonstrate that somatic activating mutations in KRAS can be associated with GSD and reveal that hyperactive KRAS signaling stimulates the formation of lymphatics in bone and impairs the development of lymphatic valves. These findings provide insight into the pathogenesis of GSD and suggest that trametinib could be an effective treatment for GSD.

Gorham-Stout Disease with Multiple Bone Involvement-Challenging Diagnosis of a Rare Disease and Literature Review

Gorham-Stout disease is a rare disorder, which may result in a poor prognosis. This disease, a rare lymphangiomatosis, is defined by progressive bone disappearance due to massive unicentric and multicentric osteolysis. Osteolytic lesions of the spine and pleura effusion are poor prognostic factors. Herein, we will present a case where the onset of disease occurred at the age of 18 with asthenia, myalgia, and major bone pain, followed by incomplete motor deficiency in the lower limbs and, later, in the upper limbs. Imaging studies (CT scan and MRI) of the patient revealed osteolytic lesions (cervical and thoracic vertebrae, rib, and clavicle) and a pathological fracture of the C7 vertebra. Surgical procedures undertaken involved replacing the affected vertebrae with bone grafting and prosthesis. The investigations performed allowed for the exclusion of inflammation, thyroid or parathyroid disease, lymphoma, neoplasia, or autoimmune disorders. A bone marrow biopsy showed osteolysis, the replacement of bone tissues with connective tissue, and chronic non-specific inflammation. The evolution was negative with almost complete osteolysis of the left clavicle, the emergence of new osteolysis areas in the lumbar vertebrae, pelvic bones, and the bilateral proximal femur, splenic nodules, chylothorax, and associated major neurological deficits. Unfortunately, this negative evolution resulted in the patient’s death a year after onset.

Sirolimus in the treatment of kaposiform lymphangiomatosis

BACKGROUND

Kaposiform lymphangiomatosis (KLA), which is a new subtype of generalized lymphatic anomaly, is a rare disease with a poor prognosis. Currently, there is no standard treatment due to the poor understanding of KLA. Sirolimus, which is an inhibitor of mammalian target of rapamycin, has been shown to have promising potential in the treatment of complicated vascular anomalies. The aim of this study was to introduce the use of sirolimus for the treatment of KLA and to highlight the challenges of managing this refractory disease.

RESULTS

We reported seven patients with KLA who received sirolimus therapy in our center. Combined with previously reported cases, 58.3% achieved a partial response, 25.0% had stable disease, and 16.7% experienced disease progression. No severe sirolimus-related adverse events occurred during treatment.

CONCLUSIONS

This study suggests that sirolimus is currently an option for the treatment of KLA, and it is hoped that more specific therapies will be developed in the future. Rapid advances in basic science and clinical practice may facilitate the development of important new treatments for KLA.

Intra-abdominal lymphatic malformation management in light of the updated International Society for the Study of Vascular Anomalies classification

BACKGROUND

The International Society for the Study of Vascular Anomalies (ISSVA) classification distinguishes between common lymphatic malformations and complex lymphatic anomalies. These entities have overlapping features but differing responses to treatment. Surgery has been the mainstream treatment in intra-abdominal lymphatic malformation, with variable reported success in the literature.

OBJECTIVE

The aim of this study was to review the outcome of different treatments for intra-abdominal lymphatic malformations in children.

MATERIALS AND METHODS

We retrospectively reviewed all intra-abdominal lymphatic malformations from 1999 to 2019 in children treated by the surgical team or followed in the vascular anomalies clinic of our institution. Children were classified into one of three groups: group A, isolated intra-abdominal lymphatic malformation; group B, common lymphatic malformation in continuity with other regions; or group C, intra-abdominal involvement as part of a complex lymphatic anomaly or associated syndrome.

RESULTS

Fifty intra-abdominal lymphatic malformations were diagnosed; five of these were excluded. In group A (n=28), the treatment was surgical resection (n=26) or sclerosing treatment (n=1), with one case of spontaneous regression; no recurrence was observed in 25 patients. In group B (n=7), three patients had partial resection and all had recurrence; four had sclerotherapy alone with good response. In group C (n=10), therapeutic options included surgery, sclerosing treatment and pharmacotherapy, with variable outcomes.

CONCLUSION

The management of intra-abdominal malformations requires a team approach. Sclerotherapy is successful in treating macrocystic lymphatic malformation. Surgery is successful in treating isolated intra-abdominal common lymphatic malformation, albeit at times at the cost of intestinal resection, which could be avoided by combining surgery with preoperative sclerotherapy. With surgery there is often limited resectability, and therefore recurrence in intra-abdominal lymphatic malformations that are part of complex lymphatic anomalies associated with syndromes, or in common lymphatic malformations in continuity with other regions. Sclerotherapy is an effective modality in these instances along with pharmacotherapy.

Gorham-Stout Disease Resulting in Spinal Deformity Treated by Fusion Surgery Combined With Everolimus Therapy: A Case Report

CASE

Gorham-Stout disease (GSD) is a rare disorder characterized by progressive localized osteolysis and lymphatic malformation. A 26-year-old woman with GSD presented to our hospital with a Cobb angle of 100° and a kyphosis angle of 88°. Everolimus therapy was initiated to control the disease prior to surgery. After halo-gravity traction for 4 weeks, we performed anterior and posterior spinal fusion. Postoperative computed tomography revealed satisfactory bone union and no significant loss of correction 1 year post-surgery.

CONCLUSION

This case suggests that anterior and posterior spinal fusion combined with everolimus therapy can be a therapeutic option for GSD.

Recent Progress in Lymphangioma

Lymphangioma is a common type of congenital vascular disease in children with a broad spectrum of clinical manifestations. The current classification of lymphangioma by International Society for the Study of Vascular Anomalies is largely based on the clinical manifestations and complications and is not sufficient for selection of therapeutic strategies and prognosis prediction. The clinical management and outcome of lymphangioma largely depend on the clinical classification and the location of the disease, ranging from spontaneous regression with no treatment to severe sequelae even with comprehensive treatment. Recently, rapid progression has been made toward elucidating the molecular pathology of lymphangioma and the development of treatments. Several signaling pathways have been revealed to be involved in the progression and development of lymphangioma, and specific inhibitors targeting these pathways have been investigated for clinical applications and clinical trials. Some drugs already currently in clinical use for other diseases were found to be effective for lymphangioma, although the mechanisms underlying the anti-tumor effects remain unclear. Molecular classification based on molecular pathology and investigation of the molecular mechanisms of current clinical drugs is the next step toward developing more effective individualized treatment of children with lymphangioma with reduced side effects.

Abnormal pulmonary lymphatic flow in patients with paediatric pulmonary lymphatic disorders: Diagnosis and treatment

Pulmonary lymphatic disorders are characterized by the presence of the abnormal lymphatic tissues in the thoracic cavity, presenting clinically as chylothorax, chylopericardium, chyloptysis, interstitial lung disease and plastic bronchitis. These conditions include: neonatal chylothorax, cardiac and non-cardiac plastic bronchitis, non-traumatic chylothorax, post congenital cardiac surgery chylothorax and complex lymphatic malformations. Recently developed lymphatic imaging techniques, such as intranodal lymphangiography and dynamic contrast enhanced magnetic resonance lymphangiography demonstrated abnormal pulmonary lymphatic flow from thoracic duct into pulmonary parenchyma as a pathophysiological mechanism of these diseases. Novel minimally invasive lymphatic interventions, such as thoracic duct embolization, interstitial lymphatic embolization and surgical lympho-venous anastomosis, provide an effective treatment of these conditions.

A case of diffuse pulmonary lymphangiomatosis with a venous anomaly presenting with acute respiratory failure and hemoptysis

Diffuse pulmonary lymphangiomatosis (DPL) is a rare lymphatic disease that can cause diverse respiratory symptoms. A 22-year-old man, whose chest CT had shown an abnormality for years, presented with acute respiratory failure due to the abrupt onset of hemoptysis. The diagnosis of DPL was confirmed by surgical lung biopsy and lymphangiography. Histopathological investigation showed dilated vascular and lymphatic vessels. DPL can cause acute and life-threatening symptoms during its chronic clinical course. A coexisting anomaly in the venous system may be present in DPL patients with hemoptysis.

Coagulation issues in vascular anomalies

Vascular anomalies, comprised of vascular tumors and malformations, are frequently associated with coagulopathy. Recognition of and familiarity with these vascular anomaly-associated hematologic abnormalities prior to surgery or interventional procedures is essential for pre-operative pre-operative planning. Complicated coagulopathies present within the framework of either Kasabach-Merritt phenomenon (KMP) or localized intravascular coagulopathy (LIC), and their management benefits from the expertise of a hematologist for optimal intra- and peri‑operative care. Furthermore, with the recent broadening of understanding of vascular anomalies and the addition of new classification sub-groups, distinctions of these two classic coagulopathy phenotypes have been recognized. This review summarizes the main features of these coagulopathies, described according to their vascular anomaly type, highlighting clinical aspects relevant to surgical management.

Vascular tumors of the mediastinum

Vascular tumors represent only a sliver of all tumors affecting the mediastinum, but they pose diagnostic challenges due to significant overlap among entities, ever-evolving classification schemes, and the exquisite rarity of some of the entities not only in the mediastinum but in pathology practice as a whole. Most of the vascular tumors are better known to the practice of soft tissue pathology, from which some of the knowledge of clinical behavior can be extrapolated. For example, the stratification of epithelioid hemangioendothelioma (EHE) into two biologically separate categories has effectively translated from the somatic soft tissues to the thorax. For other entities, the effective validation of soft tissue parameters is hindered by the small numbers of reported mediastinal cases. Many of the treatment modalities have also transferred over, with the key differences resting on the difficulty in achieving complete surgical resection for mediastinal tumors as opposed to those in the somatic soft tissues. Accordingly, systemic drug therapies have emerged as attractive options for some of the mediastinal vascular tumors, such as kaposiform hemangioendothelioma (KHE) and Kaposi sarcoma (KS). The categories presented herein mirror the classification scheme set forth by the 5th Edition WHO Classification of Soft Tissue and Bone Tumors. This review focuses on the biologically aggressive vascular neoplasms while limiting discussion of the benign entities to relevant comparisons in the differential diagnoses. While distinguishing among the benign entities has academic importance, in practice, the stakes are far higher for diagnosing the biologically aggressive tumors given their marked heterogeneity in clinical outcomes. Practical advice for problem areas in pathology will be reviewed alongside tumor pathobiology, including the latest in molecular diagnostics.

The Role of Interventional Radiologists in the Treatment of Congenital Lymphatic Malformations

Lymphatic malformations are low-flow vascular malformations that are typically apparent in the pediatric population and can cause significant functional limitations and effects on quality of life. While surgical resection has historically been the mainstay of therapy, percutaneous sclerotherapy has garnered increasing popularity due to its efficacy and low complication rates. The role of interventional radiology in the multidisciplinary management of these often complex malformations requires thorough understanding of the disease process. This article will review the pathophysiology, clinical presentation, imaging workup, and management options of lymphatic malformations. Special attention will be devoted to available sclerosants, the mammalian target of rapamycin inhibitor sirolimus, and complex lymphatic anomalies.