Genetic and Molecular Determinants of Lymphatic Malformations: Potential Targets for Therapy

Neonatal Cutaneous Vascular Anomalies

Vascular anomalies are broadly classified into 2 categories: vascular tumors and vascular malformations. Vascular anomalies frequently present as cutaneous lesions in infants. This review summarizes vascular anomalies that most commonly present as dermatologic lesions in the neonatal period, with a focus on the clinical findings, pathophysiology and histology, relevant radiographic findings, and management of common vascular anomalies such as infantile hemangiomas, congenital hemangiomas, and Kaposiform hemangioendothelioma, along with vascular malformations, including capillary, lymphatic, venous, and arteriovenous malformations.

Rare Yet Relevant: Adult Onset Cervical Lymphangioma - Our Experience and Comprehensive Review

Cervical lymphangiomas are anomalies that arise from lymphatic vessels, characterized by gradual and painless growth. While predominantly located in the neck, they may also manifest in the axilla, mediastinum, groin, and abdominal organs. Cervical lymphangioma usually occurs in children and is relatively rare in adults. The purpose of this study was to investigate the characteristics of cervical lymphangiomas in adults. We reviewed the medical records and analysed clinical data obtained from fifteen adult patients who suffered from cervical lymphangioma and were operated from January 2021 to January 2023. Out of 15 cases, 73.3% were females and 26.7% were males. All tumours were unilaterally located. Five patients had prior history of associated dyspnoea / dysphagia. All 15 cervical lymphangiomas (100%) were adjacent to the carotid sheath .Tumour size ranged from 6 cm to 15 cm, with the maximum diameter of ≥ 15 cm in two cases, between 6 cm and 10 cm in eight cases and less than 6 cm in five cases. Further, in this study all cervical lymphangiomas were surgically excised. Postoperative courses were uneventful, and histo-pathological examinations confirmed all cases to be cystic lymphangiomas. A 6 -month follow-up in all 15 cases showed no recurrences. Overall, this study underscores the importance of a multidisciplinary approach involving clinicians, radiologists, and surgeons in the management of adult cervical lymphangiomas, with an emphasis on accurate diagnosis, appropriate classification, and tailored treatment strategies to optimize patient outcomes and minimize complications.

A multi-step approach to overcome challenges in the management of head and neck lymphatic malformations, and response to treatment

BACKGROUND

Lymphatic malformations are vascular developmental anomalies varying from local superficial masses to diffuse infiltrating lesions, resulting in disfigurement. Patients' outcomes range from spontaneous regression to severe sequelae notwithstanding appropriate treatment. The current classification guides, in part, clinicians through the decision-making process, prognosis prediction and choice of therapeutic strategies. Even though the understanding of molecular basis of the disease has been recently improved, a standardized management algorithm has not been reached yet.

RESULTS

Here, we report our experience on five children with different lymphatic anomalies of the head and neck region treated by applying a multidisciplinary approach reaching a consensus among specialists on problem-solving and setting priorities.

CONCLUSIONS

Although restitutio ad integrum was rarely achieved and the burden of care is challenging for patients, caregivers and healthcare providers, this study demonstrates how the referral to expert centres can significantly improve outcomes by alleviating parental stress and ameliorating patients' quality of life. A flow-chart is proposed to guide the multidisciplinary care of children with LMs and to encourage multidisciplinary collaborative initiatives to implement dedicated patients' pathways.

Congenital Vascular and Lymphatic Diseases

Over the past several centuries, the integration of contemporary medical techniques and innovative technologies, like genetic sequencing, have played a pivotal role in enhancing our comprehension of congenital vascular and lymphatic disorders. Nonetheless, the uncommon and complex characteristics of these disorders, especially considering their formation during the intrauterine stage, present significant obstacles in diagnosis and treatment. Here, we review the intricacies of these congenital abnormalities, offering an in-depth examination of key diagnostic approaches, genetic factors, and therapeutic methods.

Percutaneous injection of sclerosant agents as an effective treatment for cystic malformations of the head and neck

PURPOSE

To evaluate the clinical and aesthetic outcome of percutaneous injection of sclerosant agents to treat head and neck cystic malformations (HNCM) and to assess their recurrence rate based on histology and site.

METHODS

Fifty-four subjects (mean age 46 years) with HNCM treated by percutaneous injection of sclerosant agents between January and December 2017 were included. Imaging and clinical data before and after the procedure were collected. Quality of Life Index, Pain Visual Analogue Scale, and Aesthetic Scale scores were measured to assess clinical and aesthetic outcomes. A size reduction of ≥ 70% assessed through the visual scale was considered significant.

RESULTS

Of the 54 HNCM, there were 26 (48%) lymphatic malformations (LM), 13 (24%) salivary epithelial duct cysts of the parotid gland, 12 (22%) salivary mucoceles, and 3 (5%) branchial cysts. A significant size reduction and a satisfactory clinical-aesthetic outcome were observed in all types of LM. The number of reinterventions was significantly associated with the number of lesions (p < 0.001). The lowest number of interventions was observed in macrocystic lymphatic malformations (average of 1.2 interventions). All salivary epithelial duct cysts showed a significant reduction in size, a satisfactory clinical-aesthetic outcome, and an average of 1.16 interventions per patient. Mucoceles had a worse response, with only 3/14 patients showing a satisfactory and long-lasting clinical outcome (average of 1.16 interventions). Treatment of branchial cysts showed the worst outcome with a limited clinical response (3/3).

CONCLUSION

Percutaneous injection of sclerosant agents may be considered as a first-line treatment for LM and salivary epithelial duct cysts.

Genetic causes of lymphatic disorders: recent updates on the clinical and molecular aspects of lymphatic disease

PURPOSE OF REVIEW

The lymphatic system facilitates several key functions that limit significant morbidity and mortality. Despite the impact and burden of lymphatic disorders, there are many remaining disorders whose genetic substrate remains unknown. The purpose of this review is to provide an update on the genetic causes of lymphatic disorders, while reporting on newly proposed clinical classifications of lymphatic disease.

RECENT FINDINGS

We reviewed several new mutations in genes that have been identified as potential causes of lymphatic disorders including: MDFIC, EPHB 4 , and ANGPT2. Furthermore, the traditional St. George's Classification system for primary lymphatic anomalies has been updated to reflect the use of genetic testing, both as a tool for the clinical identification of lymphatic disease and as a method through which new sub-classifications of lymphatic disorders have been established within this framework. Finally, we highlighted recent clinical studies that have explored the impact of therapies such as sirolimus, ketoprofen, and acebilustat on lymphatic disorders.

SUMMARY

Despite a growing body of evidence, current literature demonstrates a persistent gap in the number of known genes responsible for lymphatic disease entities. Recent clinical classification tools have been introduced in order to integrate traditional symptom- and time-based diagnostic approaches with modern genetic classifications, as highlighted in the updated St. George's classification system. With the introduction of this novel approach, clinicians may be better equipped to recognize established disease and, potentially, to identify novel causal mutations. Further research is needed to identify additional genetic causes of disease and to optimize current clinical tools for diagnosis and treatment.

A Review of the Current State and Future Directions for Management of Scalp and Facial Vascular Malformations

Vascular malformations are structural abnormalities that are thought to result from errors in vasculogenesis and angiogenesis during embryogenesis. Vascular malformations of the scalp present unique management challenges due to aesthetic and functional implications. This review examines the pathophysiology, clinical presentation, and management techniques for six common types of vascular malformations of the face and scalp : infantile hemangioma, capillary malformations, venous malformations, lymphatic malformations, arteriovenous malformations, and arteriovenous fistulas. These lesions range from common to rare, and have very different natural histories and management paradigms. There has been increasing understanding of the molecular pathways that are altered in association with these vascular lesions and these molecular targets may represent novel strategies of treating lesions that have historically been approached from a structural perspective only.

Work-Up and Treatment Strategies for Individuals with PIK3CA-Related Disorders: A Consensus of Experts from the Scientific Committee of the Italian Macrodactyly and PROS Association

PIK3CA-related disorders encompass many rare and ultra-rare conditions caused by somatic genetic variants that hyperactivate the PI3K-AKT-mTOR signaling pathway, which is essential for cell cycle control. PIK3CA-related disorders include PIK3CA-related overgrowth spectrum (PROS), PIK3CA-related vascular malformations and PIK3CA-related non-vascular lesions. Phenotypes are extremely heterogeneous and overlapping. Therefore, diagnosis and management frequently involve various health specialists. Given the rarity of these disorders and the limited number of centers offering optimal care, the Scientific Committee of the Italian Macrodactyly and PROS Association has proposed a revision of the most recent recommendations for the diagnosis, molecular testing, clinical management, follow-up, and treatment strategies. These recommendations give insight on molecular diagnosis, eligible samples, preferable sequencing, and validation methods and management of negative results. The purpose of this paper is to promote collaboration between health care centers and clinicians with a joint shared approach. Finally, we suggest the direction of present and future research studies, including new systemic target therapies, which are currently under evaluation in several clinical trials, such as specific inhibitors that can be employed to downregulate the signaling pathway.

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.

Sudden Appearance of a Palpable Chest Wall Mass Secondary to Macrocystic Lymphatic Malformation: A Case Report

Chest wall lymphatic malformations are rare and can pose a diagnostic dilemma, particularly if they present abruptly. This case report describes a 15-month-old male toddler presenting with a left lateral chest mass. Histopathology of the surgically excised mass confirmed the diagnosis of a macrocystic lymphatic malformation. Furthermore, there was no recurrence of the lesion in the two-year follow-up period.

The Genetic Architecture of Vascular Anomalies: Current Data and Future Therapeutic Perspectives Correlated with Molecular Mechanisms

Vascular anomalies (VAs) are morphogenesis defects of the vascular system (arteries, capillaries, veins, lymphatic vessels) singularly or in complex combinations, sometimes with a severe impact on the quality of life. The progress made in recent years with the identification of the key molecular pathways (PI3K/AKT/mTOR and RAS/BRAF/MAPK/ERK) and the gene mutations that lead to the appearance of VAs has allowed the deciphering of their complex genetic architecture. Understanding these mechanisms is critical both for the correct definition of the phenotype and classification of VAs, as well as for the initiation of an optimal therapy and the development of new targeted therapies. The purpose of this review is to present in synthesis the current data related to the genetic factors involved in the etiology of VAs, as well as the possible directions for future research. We analyzed the data from the literature related to VAs, using databases (Google Scholar, PubMed, MEDLINE, OMIM, MedGen, Orphanet) and ClinicalTrials.gov. The obtained results revealed that the phenotypic variability of VAs is correlated with genetic heterogeneity. The identification of new genetic factors and the molecular mechanisms in which they intervene, will allow the development of modern therapies that act targeted as a personalized therapy. We emphasize the importance of the geneticist in the diagnosis and treatment of VAs, as part of a multidisciplinary team involved in the management of VAs.