Sildenafil for microcystic lymphatic malformations of the head and neck: A prospective study

Management and Outcomes of Pediatric Lymphatic Malformations: A Systematic Review From the APSA Outcomes and Evidence-Based Practice Committee

BACKGROUND

Significant variation in management strategies for lymphatic malformations (LMs) in children persists. The goal of this systematic review is to summarize outcomes for medical therapy, sclerotherapy, and surgery, and to provide evidence-based recommendations regarding the treatment.

METHODS

Three questions regarding LM management were generated according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Publicly available databases were queried to identify articles published from January 1, 1990, to December 31, 2021. A consensus statement of recommendations was generated in response to each question.

RESULTS

The initial search identified 9326 abstracts, each reviewed by two authors. A total of 600 abstracts met selection criteria for full manuscript review with 202 subsequently utilized for extraction of data. Medical therapy, such as sirolimus, can be used as an adjunct with percutaneous treatments or surgery, or for extensive LM. Sclerotherapy can achieve partial or complete response in over 90% of patients and is most effective for macrocystic lesions. Depending on the size, extent, and location of the malformation, surgery can be considered.

CONCLUSION

Evidence supporting best practices for the safety and effectiveness of management for LMs is currently of moderate quality. Many patients benefit from multi-modal treatment determined by the extent and type of LM. A multidisciplinary approach is recommended to determine the optimal individualized treatment for each patient.

LEVEL OF EVIDENCE: 4

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

Lymphatic malformations are fluid-filled congenital defects of lymphatic channels occurring in 1 in 6000 to 16,000 patients. There are various types, and they often exist in conjunction with other congenital anomalies and vascular malformations. Great strides have been made in understanding these malformations in recent years. This review summarize known molecular and embryological precursors for lymphangiogenesis. Gene mutations and dysregulations implicated in pathogenesis of lymphatic malformations are discussed. Finally, we touch on current and developing therapies with special attention on targeted biotherapeutics.

Management of lymphatic vascular malformations: A systematic review of the literature

OBJECTIVE

Lymphatic malformations (LM) are common congenital vascular lesions, most often diagnosed at birth. They deform local anatomy and can be life-threatening if they compress the aerodigestive tract or other vital structures. Significant progress has been made in the treatment of LMs in the past 20 years. We conducted a systematic review of the literature on the management of LMs.

METHODS

On September 21, 2020, we searched PubMed/MEDLINE for studies published from 2000 to 2020 reporting outcomes of invasive and pharmacologic treatment of LMs.

RESULTS

A total of 251 studies met the eligibility criteria. Surgery has continued to be a mainstay in the management of LMs, especially in the treatment of microcystic and mixed lesions. Sclerotherapy has emerged as a first-line treatment of macrocystic LMs and as an adjunctive therapy used in combination with surgery for other lesions. Sirolimus, a strong inhibitor of mTOR (mechanistic target of rapamycin), has shown tremendous promise in the treatment of LMs, as both an oral and a topical agent. Recent investigations have shown the potential of targeted small molecule modulators of cellular pathways in the treatment of LMs.

CONCLUSIONS

Multiple invasive and pharmacologic therapies have been shown to be effective in the treatment of LMs. Future research should focus on rigorous, prospective comparisons of these treatment modalities.

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.

Endoscopy-assisted, transoral submucosal coblation for pediatric retropharyngeal lymphatic malformations

OBJECTIVE

Retropharyngeal lymphatic malformations (LMs) are uncommon congenital anomalies. Open surgery, sclerotherapy and various pharmaceutical agents have been described to manage these lesions. However, when such lesions involve the retropharyngeal space with evidence of airway compromise, none of the above aforementioned modalities has shown superior result without repeated imaging and procedures. We describe the use of radiofrequency ablation (Coblation) in an endoscopic-assisted, transoral approach as a one-off treatment for pediatric retropharyngeal lymphatic malformations.

METHODS

Six patients with retropharyngeal lymphatic malformations, presented with airway compromise, were treated with endoscopic-assisted, transoral submucosal coblation in our unit between April 2015 to August 2018. We retrospectively reviewed their medical records, imaging and endoscopic findings.

RESULTS

Five out of our six patients had LMs involving only the retropharyngeal space, who received the coblation as their sole treatment. One patient with extensive LMs involving multiple neck compartments received coblation to the retropharyngeal part as an adjunct procedure. The average operation time was 62.8 min, and the average intraoperative blood loss was 3.8 ml. All patients were safely extubated immediately after the surgery. None required admission to pediatric intensive care unit (PICU), nor prolonged dysphagia reported. They were observed for 2-5 days post operatively. The average follow up was 28 months (1-5 years) and none required re-operation to date.

CONCLUSIONS

We presented our approach and outcome of 6 children with endoscopic-assisted, transoral submucosal coblation to retropharyngeal lymphatic malformation. We believe it is a safe and effective primary treatment to these patients, and a possible adjunct to complex vascular malformation involving multiple sites.

Effect of long-term phosphodiesterase-5 inhibitor use on refractory lymphatic malformations in adult and teen patients

Lymphatic malformations (LMs) are rare congenital anomalies. LMs are often refractory to standard treatments, including surgical resection, debulking, and sclerotherapy. Use of sildenafil, a phosphodiesterase-5 inhibitor, for treatment of pediatric LMs has been reported with demonstrated benefit to some patients. This case series reports treatment of three patients (aged 14-37 years) suffering from complicated or refractory LMs with a low-dose oral phosphodiesterase-5 inhibitor, resulting in significant clinical improvement.

Common (Cystic) Lymphatic Malformations: Current Knowledge and Management

The approach to treating common (cystic) lymphatic malformations (LMs) has evolved significantly over the last decade due to clinical research and recent developments in molecular biology. Surgery, sclerosing agents, and medical drugs with specific targets for biological therapy have been reported for the management of LMs. We will discuss the importance to standardize the location and imaging characterization of LMs to improve the knowledge about the outcome of the different therapeutic options. Our goal is to help the reader understand the different options for the management of LMs with the balance between risk and benefit for the patients.

Thoracic involvement of diffuse lymphangiomatosis successfully treated with sildenafil

General lymphatic anomaly (GLA) is a very rare disorder, characterised by multifocal lymphatic malformations into various tissues that is due to congenital abnormalities of lymphatic development. No treatment has ever proved its efficiency.We report a 22-year-old man with recurrent bronchial casts due to thoracic involvement of GLA. After a 6-month treatment with sildenafil (20 mg three times a day), a phosphodiesterase 5 inhibitor, chest CT scan showed a complete regression of ground-glass opacities and lung function test results improved substantially and remained stable for 1 year. The treatment was well tolerated.This observation suggests that sildenafil may be a therapeutic approach to be tested in thoracic involvement of GLA.

Advances in the Medical Management of Vascular Anomalies

Vascular anomalies comprise a spectrum of diseases that are broadly classified as tumors and malformations. Diagnosis is often challenging, given a wide range of clinical presentations with overlapping signs and symptoms. Accurate diagnosis is critical to determine prognosis and to generate a management plan, which frequently involves multiple subspecialists during different phases of treatment. An updated classification system provides structure and clear, consistent terminology, allowing for improved diagnosis, provider communication, and collaboration. Historically, treatment of vascular anomalies was primarily surgical and medical therapies were limited or ineffective. Recent discoveries of pharmacologic agents effective in treating vascular anomalies have broadened our medical therapeutic options, limiting the need for unnecessary or high-risk procedures and improving patients' quality of life.

Long-Term Follow-Up of Lymphatic Malformations in Children Treated with Sildenafil

BACKGROUND/OBJECTIVES

Lymphatic malformations (LMs) are challenging to treat. Reports on the benefits of sildenafil for LM management have been mixed. This study evaluated long-term clinical outcomes of pediatric LM patients after sildenafil treatment.

METHODS

A retrospective chart review was performed on pediatric LM patients treated with sildenafil in the past 5 years. Patients were also contacted to complete a survey of comprehensive questions about their LM after sildenafil and subsequent interventions.

RESULTS

Of 12 patients identified, 10 (83.3%) participated in the follow-up survey. The average age was 8 years (range 4-16 yrs), median treatment duration was 9 months, and the average time of follow-up after sildenafil was 4 years; one patient is still taking sildenafil. Ten patients surveyed (83.3%) reported positive therapeutic response, with improvement in the size and compressibility of their LM during posttreatment clinical visits. Six received additional interventions (four sirolimus, one sclerotherapy, one surgery) after sildenafil was discontinued, with all but one reporting a positive response to subsequent interventions. Minor side effects at the time of sildenafil treatment included mild flushing, dizziness, and transient nausea, but no adverse effects were reported at the long-term follow-up.

CONCLUSION

This is the first report of long-term follow-up of pediatric LM patients treated with sildenafil. Our findings suggest that sildenafil is beneficial for the symptomatic treatment of LMs. Additional analysis on the role of sildenafil as adjuvant therapy is necessary to optimize the use of this medication in the management of complex LMs.

Efficacy and safety of oral sildenafil in treatment of pediatric head and neck lymphatic malformations

CONCLUSIONS

Low dose oral sildenafil citrate tablets are safe and effective to decrease the lesions volume in some LMs children, especially with macrocystic lesion or mixed type.

OBJECTIVE

To evaluate the efficacy and safety of oral sildenafil in treatment of pediatric head and neck lymphatic malformations (LMs).

SUBJECTS AND METHODS

In this open-label study, 21 children diagnosed with LMs were given oral sildenafil and stopped at week 24. Volume change of lesions compared with baseline was used to evaluate therapeutic outcome. The improvement of various symptoms and the adverse effects of sildenafil were recorded during the follow-up period.

RESULTS

Eight patients (38.0%) showed excellent improvement (>75-100%), one patient (4.8%) had good (>50-75%), two patients (9.6%) had fair (>25-50%), three patients (14.3%) had minimal (0-25%), and seven patients (33.3%) had no improvement. The snoring or stridor completely disappeared in two subjects, although there was no apparent decrease in LMs size. Moreover, all three patients with macrocystic lesions displayed a positive response to sildenafil treatment, followed by mixed type (9/12, 75%). Only two out of six patients with microcystic lesions had minimal clearance. Only four patients showed transient mild diarrhea, there was no other adverse effect in this series.

Oral sildenafil as a treatment option for lymphatic malformations in PIK3CA-related tissue overgrowth syndromes

Patients with extensive lymphatic malformations associated with tissue overgrowth syndromes (such as Klippel-Trenaunay syndrome and CLOVES) often pose a therapeutic challenge for physicians. In recent years, it has been suggested that oral sildenafil therapy might be used to treat congenital lymphatic malformations. However, this possible new therapy has not yet been used in patients with lymphatic malformations associated with tissue overgrowth syndromes. A 30-year-old man with extensive capillary-lymphatic malformations of the right leg and thorax, and a tissue overgrowth syndrome caused by a somatic mutation in the PIK3CA gene, was treated with oral sildenafil due to symptoms of pain, dyspnea, and functional impairment. Several weeks after the start of the treatment, the patient reported softening of the lymphatic malformation and a significant improvement of his symptoms and physical condition. So far, sildenafil is still considered a last resort in the treatment of complex treatment-resistant lymphatic malformations. With this case report, we demonstrate that sildenafil could also be an alternative treatment option for lymphatic malformations in patients with syndromes belonging to the PIK3CA-related overgrowth spectrum.

Pediatric lymphatic malformations: evolving understanding and therapeutic options

Multimodal treatment of lymphatic malformations continues to expand as new information about the biology and genetics of these lesions is discovered, along with knowledge gained from clinical practice. A patient-centered approach, ideally provided by a multidisciplinary medical and surgical team, should guide timing and modality of treatment. Current treatment options include observation, surgery, sclerotherapy, radiofrequency ablation, and laser therapy. New medical and surgical therapies are emerging, and include sildenafil, propranolol, sirolimus, and vascularized lymph node transfer. The primary focus of management is to support and optimize these patients' quality of life. Researchers continue to study lymphatic malformations with the goal of increasing therapeutic options and developing effective clinical pathways for these complicated lesions.

[Lymphatic malformations in the head and neck area]

Lymphatic malformations are congenital malformations of the lymphatic system. They are mainly located in the head and neck area, and grow proportional to the patients' body growth. Depending on the morphology, it can be distinguished between macrocystic, microcystic and mixed lymphatic malformations. Due to their infiltrative growth, microcystic lymphatic malformations are particularly difficult to treat. Therapeutic approaches include conventional surgical resection, laser therapy, sclerotherapy and systemic drug therapies.