The role of key biomarkers in lymphatic malformation: An updated review.

The lymphatic system, crucial for tissue fluid balance and immune surveillance, can be severely impacted by disorders that hinder its activities. Lymphatic malformations (LMs) are caused by fluid accumulation in tissues owing to defects in lymphatic channel formation, the obstruction of lymphatic vessels or injury to lymphatic tissues. Somatic mutations, varying in symptoms based on lesions' location and size, provide insights into their molecular pathogenesis by identifying LMs' genetic causes. In this review, we collected the most recent findings about the role of genetic and inflammatory biomarkers in LMs that control the formation of these malformations. A thorough evaluation of the literature from 2000 to the present was conducted using the PubMed and Google Scholar databases. Although it is obvious that the vascular endothelial growth factor receptor 3 mutation accounts for a significant proportion of LM patients, several mutations in other genes thought to be linked to LM have also been discovered. Also, inflammatory mediators like interleukin-6, interleukin-8, tumor necrosis factor-alpha and mammalian target of rapamycin are the most commonly associated biomarkers with LM. Understanding the mutations and genes expression responsible for the abnormalities in lymphatic endothelial cells could lead to novel therapeutic strategies based on molecular pathways.

Microcystic lymphatic malformations in Turner syndrome are due to somatic mosaicism of PIK3CA.

Turner syndrome (45,X) is caused by a complete or partial absence of a single X chromosome. Vascular malformations occur due to abnormal development of blood and/or lymphatic vessels. They arise from either somatic or germline pathogenic variants in the genes regulating growth and apoptosis of vascular channels. Aortic abnormalities are a common, known vascular anomaly of Turner syndrome. However, previous studies have described other vascular malformations as a rare feature of Turner syndrome and suggested that vascular abnormalities in individuals with Turner syndrome may be more generalized. In this study, we describe two individuals with co-occurrence of Turner syndrome and vascular malformations with a lymphatic component. In these individuals, genetic testing of the lesional tissue revealed a somatic pathogenic variant in PIK3CA-a known and common cause of lymphatic malformations. Based on this finding, we conclude that the vascular malformations presented here and likely those previously in the literature are not a rare part of the clinical spectrum of Turner syndrome, but rather a separate clinical entity that may or may not co-occur in individuals with Turner syndrome.

Mesenteric and omental lymphatic malformations in children: seven-year surgical experience from two centers in China.

PURPOSE: To compare the clinical characteristics, surgical management and prognosis of mesenteric lymphatic malformations (ML) and omental lymphatic malformations (OL) in children. METHODS: This retrospective study included 148 ML patients and 53 OL patients who underwent surgical treatment at two centers between January 2016 and December 2022. Details about the patients' clinical characteristics, cyst characteristics, preoperative complications, surgical methods, and prognosis were retrieved and compared. RESULTS: No significant differences in sex ratio, prenatal diagnosis, or age of diagnosis were noted between ML and OL patients. Vomiting was more common in ML patients than in OL patients (46.6% vs. 22.6%, P = 0.002), but OL patients were more likely to be misdiagnosed (35.8% vs. 18.9%, P = 0.012). The size of the cysts in OL patients was significantly larger than that in ML patients (14.0 [4.0-30.0] vs. 10.0 [2.0-50.0] cm, P<0.001), and cysts with turbid fluid were more common in OL patients (38.0% vs. 20.6%, P<0.001). More OL patients than ML patients had preoperative hemorrhage or infection of cysts (41.5% vs. 31.8%, P<0.016). Cyst excision was performed in 137 (92.6%) ML patients and 51 (96.2%) OL patients, and the incidence of postoperative complications was lower (12.6% vs. 4.2%, P = 0.165) among OL patients. The main postoperative complications included adhesive ileus and recurrence of cysts. Additionally, more OL patients than ML patients were treated with laparoscopic surgery (69.8% vs. 39.2%, P<0.001). CONCLUSIONS: There were differences in clinical characteristics, cyst characteristics and preoperative complications between ML and OL patients. Cyst excision was the most common surgical method that was used to treat both ML and OL patients, and laparoscopic surgery could be a feasible surgical approach for treating OL patients with a good prognosis. TRIAL REGISTRATION: Retrospectively registered.

Lymphoscintigraphy Findings are Associated with Outcome in Children with Chylothorax After Cardiac Surgery.

Postoperative chylothorax in patients with congenital heart diseases (CHD) results in poor outcomes if anatomical and functional abnormalities of the lymphatic system are present. While these abnormalities are typically diagnosed by intranodal lymphangiography and dynamic contrast magnetic resonance lymphangiography, the usefulness of lymphoscintigraphy in these patients has not been evaluated. Between January 2019 and December 2021, 28 lymphoscintigraphies were performed in our institution for investigating prolonged pleural effusion after cardiac surgery. The images were assessed by three board-certified pediatric cardiologists retrospectively to determine the likelihood of a central lymphatic flow disorder. The likelihood was scored (range 1-3) based on structural abnormalities and congestive flow in the lymphatic system. Those scores were summed and the likelihood was categorized as low to intermediate (< 8 points) or high (8 or 9 points). Median age at lymphoscintigraphy was 129 days (IQR, 41-412 days), it was performed at a median of 22 days (IQR, 17-43) after surgery, and median score was 6 points (IQR, 4-7.5). Kendall's coefficient of concordance (0.867; p < 0.05) indicated high inter-rater reliability. Overall survival at 6 months after surgery was 92.5% in the low-to-intermediate group but 68.6% in the high group (p < 0.05), and duration of postoperative thoracic drainage was 27 and 58 days, respectively (p < 0.05). Lymphatic abnormalities detected by lymphoscintigraphy were associated with poorer outcomes. Lymphoscintigraphy was thought to be useful in assessing anatomic and functional lymphatic abnormalities, despite its minimal invasiveness.

[The Duplicity of Incidents: Cervical Lymphatic Malformation in two Newborns]. / Die Duplizität der Ereignisse: Zervikale lymphatische Malformation bei zwei Neugeborenen.

We report on two neonates born the same day, both with an isolated cervical lymphatic malformation. Cervical masses were detected by ultrasound late in the third trimester. Following interdisciplinary case conferences, a caesarean section in the presence of a neonatal team was the chosen delivery mode in both cases. Delivery and transition of the newborns were uneventful. The suspected diagnosis was confirmed by postnatal MRIs, which demonstrated neither associated malformations nor compression of vital structures. Therefore, an expectant approach was chosen for the newborn with the smaller lesion. The other newborn featured a sizeable lymphatic malformation, and due to consecutive head tilt, sclerotherapy was initiated in its second week of life. Our case report outlines the challenges of a rare connatal malformation. Guidelines are often missing. Individual decisions regarding delivery mode, diagnostics and therapy have to be made on an interdisciplinary basis and patients as well as parents need counseling and support over a long period. All the more significant is good, interdisciplinary collaboration between the involved disciplines.

Endoscopic Resection for Vascular Anomalies in Children: A New Standard.

OBJECTIVE: To report an innovative endoscopic surgery for subcutaneous vascular malformations and intramuscular fibro-adipose vascular anomaly (FAVA) at our center. BACKGROUND: Historically, open surgical resection has been the treatment of choice. Recent advances in minimally invasive surgery have led to the successful application of endoscopic resection techniques for the surgical management of diseases of soft tissue. METHODS: Patients who underwent endoscopic resection of vascular anomalies were included in this retrospective review. Data were extracted from our Vascular Anomalies Center database between September 2019 and October 2022, including sex, age, symptoms, diagnosis, sites of surgery, previous treatment, surgery, and follow-up. RESULTS: There were 13 females and 15 males in the current study, with ages ranging from 1 to 17 years. The diagnoses included microcystic lymphatic malformation (LM) (n = 8), Klippel-Trénaunay syndrome (n = 7), venous malformation (n = 6), FAVA (n = 6), and mixed cystic LM (n = 1). Surgical sites included the lower extremity (n = 24), abdominal wall (n = 2), upper extremity (n = 1), and thoracic wall (n = 1). Five patients had an intramuscular lesion (FAVA). The endoscopic technique used 2 or 3 small ports in a gas inflation manner. Surgery included thrombectomy, radical resection, and debulking of vascular anomalies. Postoperative sclerotherapy with bleomycin was performed through a drainage tube in 6 patients with microcystic LM. Technical success was obtained in 27 patients. The conversion to open surgery was performed in one patient owing to the deep location of the lesion. No wound-related complication was observed. CONCLUSIONS: Endoscopic surgery is a minimally invasive, effective, and safe treatment for subcutaneous vascular malformations and intramuscular FAVA. This approach can set a new standard that minimizes wound complications and reduces recovery time in patients undergoing resection for benign soft-tissue lesions.

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

BACKGROUND: Kaposiform lymphangiomatosis (KLA) is a complex lymphatic anomaly involving most commonly the mediastinum, lung, skin and bones with few effective treatments. In recent years, RAS-MAPK pathway mutations were shown to underlie the pathogenesis of several complex lymphatic anomalies. Specifically, an activating NRAS mutation (p.Q61R) was found in the majority of KLA patients. Recent reports demonstrated promising results of treatment with the MEK inhibitor, Trametinib, in patients with complex lymphatic anomalies harboring gain of function mutations in ARAF and SOS1, as well as loss of function mutation in the CBL gene, a negative regulator of the RAS-MAPK pathway. We present a 9-year-old child with a severe case of KLA harboring the typical NRAS (p.Q61R) mutation detected by plasma-derived cell free DNA, responsive to trametinib therapy. METHODS: The NRAS somatic mutation was detected from plasma cfDNA using droplet digital PCR. Concurrent in-vitro studies of trametinib activity on mutant NRAS affected lymphatic endothelial cells were performed using a three-dimensional spheroid sprouting assay. RESULTS: Trametinib treatment lead to resolution of lifelong thrombocytopenia, improvement of pulmonary function tests and wellbeing, as well as weaning from prolonged systemic steroid treatment. Concurrent studies of mutant NRAS-expressing cells showed enhanced lymphangiogenic capacity along with over activation of the RAS-MAPK and PI3K-AKT-mTOR pathways, both reversed by trametinib. CONCLUSIONS: Trametinib treatment can substantially change the prognosis of patients with RAS pathway associated lymphatic anomalies. IMPACT: This is the first description of successful trametinib treatment of a patient with KLA harboring the most characteristic NRAS p.Q61R mutation. Treatment can significantly change the prognosis of patients with RAS pathway-associated lymphatic anomalies. We devised an in vitro model of KLA enabling a reproducible method for the continued study of disease pathogenesis. Mutated NRAS p.Q61R cells demonstrated increased lymphangiogenic capacity.

Lymphatic Malformations: Genetics, Mechanisms and Therapeutic Strategies.

Lymphatic vessels maintain tissue fluid homeostasis by returning to blood circulation interstitial fluid that has extravasated from the blood capillaries. They provide a trafficking route for cells of the immune system, thus critically contributing to immune surveillance. Developmental or functional defects in the lymphatic vessels, their obstruction or damage, lead to accumulation of fluid in tissues, resulting in lymphedema. Here we discuss developmental lymphatic anomalies called lymphatic malformations and complex lymphatic anomalies that manifest as localized or multifocal lesions of the lymphatic vasculature, respectively. They are rare diseases that are caused mostly by somatic mutations and can present with variable symptoms based upon the size and location of the lesions composed of fluid-filled cisterns or channels. Substantial progress has been made recently in understanding the molecular basis of their pathogenesis through the identification of their genetic causes, combined with the elucidation of the underlying mechanisms in animal disease models and patient-derived lymphatic endothelial cells. Most of the solitary somatic mutations that cause lymphatic malformations and complex lymphatic anomalies occur in genes that encode components of oncogenic growth factor signal transduction pathways. This has led to successful repurposing of some targeted cancer therapeutics to the treatment of lymphatic malformations and complex lymphatic anomalies. Apart from the mutations that act as lymphatic endothelial cell-autonomous drivers of these anomalies, current evidence points to superimposed paracrine mechanisms that critically contribute to disease pathogenesis and thus provide additional targets for therapeutic intervention. Here, we review these advances and discuss new treatment strategies that are based on the recently identified molecular pathways.

Vascular and Lymphatic Malformations: Perspectives From Human and Vertebrate Studies.

Vascular malformations, affecting ≈1% to 1.5% of the population, comprise a spectrum of developmental patterning defects of capillaries, arteries, veins, and/or lymphatics. The majority of vascular malformations occur sporadically; however, inherited malformations exist as a part of complex congenital diseases. The malformations, ranging from birthmarks to life-threatening conditions, are present at birth, but may reveal signs and symptoms-including pain, bleeding, disfigurement, and functional defects of vital organs-in infancy, childhood, or adulthood. Vascular malformations often exhibit recurrent patterns at affected sites due to the lack of curative treatments. This review series provides a state-of-the-art assessment of vascular malformation research at basic, clinical, genetic, and translational levels.

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.

Investigation into the genetics of fetal congenital lymphatic anomalies.

OBJECTIVE: Congenital lymphatic anomalies (LAs) arise due to defects in lymphatic development and often present in utero as pleural effusion, chylothorax, nuchal and soft tissue edema, ascites, or hydrops. Many LAs are caused by single nucleotide variants, which are not detected on routine prenatal testing. METHODS: Demographic data were compared between two subcohorts, those with clinically significant fetal edema (CSFE) and isolated fetal edema. A targeted variant analysis of LA genes was performed using American College of Medical Genetics criteria on whole exome sequencing (WES) data generated for 71 fetal edema cases who remained undiagnosed after standard workup. RESULTS: CSFE cases had poor outcomes, including preterm delivery, demise, and maternal preeclampsia. Pathogenic and likely pathogenic variants were identified in 7% (5/71) of cases, including variants in RASopathy genes, RASA1, SOS1, PTPN11, and a novel PIEZO1 variant. Variants of uncertain significance (VOUS) were identified in 45% (32/71) of cases. In CSFEs, VOUS were found in CELSR1, EPHB4, TIE1, PIEZO1, ITGA9, RASopathy genes, SOS1, SOS2, and RAF1. CONCLUSIONS: WES identified pathogenic and likely pathogenic variants and VOUS in LA genes in 51% of fetal edema cases, supporting WES and expanded hydrops panels in cases of idiopathic fetal hydrops and fluid collections.

How to Start a Lymphatic Program.

Many patients are born with lymphatic abnormalities or are susceptible to pathology following cardiac surgery. It therefore becomes important to evaluate and treat lymphatic disorders in centers performing congenital heart surgery. Programs can make strides towards starting a lymphatic branch if appropriately equipped with proper staff, tools, and other capabilities to perform lymphatic system access, imaging, and intervention. In reality, many of these components already exist in most centers, and a successful and comprehensive program can be established by enlisting these already established services.

Curettage and sclerotherapy technique: A hybrid approach to superficial lymphatic malformation.

OBJECTIVE: To describe the curettage and sclerotherapy technique, a hybrid approach to treatment for superficial lymphatic malformations. METHODS: A retrospective analysis of a lymphatic malformation data base was performed. Patients with superficial lymphatic malformation treated by curettage and sclerotherapy technique with bleomycin were included in this study. Safety and efficacy of the curettage and sclerotherapy technique with bleomycin were evaluated. RESULTS: Between September 2019 and October 2021, 10 consecutive patients (male/female ratio: 4:6; mean age, 10.9 years; range, 3-35 years) presented with superficial lymphatic malformations that were subsequently treated by curettage and sclerotherapy technique with bleomycin. All lesions were located on the trunk and extremities. Each patient received one treatment session and a mean follow-up of 12 months. We observed minor complications. No postoperative infections occurred in this series. No patient developed skin ulceration or necrosis. Scarring and recurrence occurred in one patient. Complete regression was confirmed for all 10 patients by photographic evaluation. CONCLUSION: A curettage and sclerotherapy technique is proposed to treat superficial lymphatic malformation in this study. This technique seems to be safe and highly effective.

Spectrum of lymphatic anomalies in patients with RASA1-related CM-AVM.

BACKGROUND: Capillary malformation-arteriovenous malformation (CM-AVM) is characterized by multifocal fast-flow capillary malformations, sometimes with arteriovenous malformations/fistulas, skeletal/soft tissue overgrowth, telangiectasias, or Bier spots. Lymphatic abnormalities are infrequently reported. We describe seven patients with CM-AVM and lymphatic anomalies. METHODS: Following IRB approval, we identified patients with CM-AVM and lymphatic anomalies seen at the Vascular Anomalies Center at Boston Children's Hospital from 2003 to 2023. We retrospectively reviewed records for clinical, genetic, laboratory, and imaging findings. RESULTS: We found seven patients with CM-AVM and lymphatic abnormalities. Five patients were diagnosed prenatally: four with pleural effusions (including one suspected chylothorax) and one with ascites. Pleural effusions resolved after neonatal drainage in three patients and fetal thoracentesis in the fourth; however, fluid rapidly reaccumulated in this fetus causing hydrops. Ascites resolved after neonatal paracentesis, recurred at 2 months, and spontaneously resolved at 5 years; magnetic resonance lymphangiography for recurrence at age 19 years suggested a central conducting lymphatic anomaly (CCLA), and at age 20 years a right spermatic cord/scrotal lymphatic malformation (LM) was detected. Chylous pericardial effusion presented in a sixth patient at 2 months and disappeared after pericardiocentesis. A seventh patient was diagnosed with a left lower extremity LM at 16 months. Six patients underwent genetic testing, and all had RASA1 mutation. RASA1 variant was novel in three patients (c.1495delinsCTACC, c.434_451delinsA, c.2648del), previously reported in two (c.2603+1G>A, c.475_476del), and unavailable in another. Median follow-up age was 5.8 years (4 months-20 years). CONCLUSION: CM-AVM may be associated with lymphatic anomalies, including pericardial/pleural effusions, ascites, CCLA, and LM.

Management of the head and neck lymphatic malformations in children: A 7-year experience of 91 surgical cases.

OBJECTIVE: To review the clinical characteristics and treatment outcomes of head and neck lymphatic malformations (HNLMs) in children. METHODS: A retrospective study of 91 patients with HNLMs was performed. RESULTS: The age ranged from 1 day to 14 years, of which 82.4 % (75/91) were under 2 years old and 45.1 % (41/91) were diagnosed at birth. The diagnostic rates of ultrasound, CT and MRI were 80.2 % (73/91), 90.1 % (82/91) and 100 % (8/8) respectively. There were 2 cases of complete excision, 8 of bleomycin sclerotherapy, and 81 of subtotal resection combined with bleomycin irrigation. Followed up for 3-93 months, all 91 cases were cured. CONCLUSIONS: HNLMs mostly occur within 2 years old, and nearly half of them are present at birth. Characteristic imaging findings can assist clinicians in diagnosis and treatment plan. Subtotal resection combined with bleomycin irrigation may be an appropriate first-line therapy for HNLMs involving the vital anatomical structures.

Association between malformation type, location and functional deficits in lymphatic malformations of the head and neck in children.

PURPOSE: Lymphatic malformations (LM) are congenital malformations of the lymphatic system, mainly located in the head and neck area. They can be staged based on location according to de Serres and based on different morbidity items using the Cologne Disease Score (CDS), a clinical staging system. In many cases, functional impairment greatly affects the life of patients suffering from lymphatic malformations. The present study aims to analyze a cohort of pediatric patients with LM. METHODS: A retrospective analysis of 144 pediatric patients with head and neck LM was performed. Location, type of malformation (microcystic, macrocystic, mixed), scoring according to two different scoring systems and therapy were analyzed. Kruskal-Wallis test was used to analyze the difference in CDS between the patient groups and Dunn's test was used for post-hoc pairwise comparison. RESULTS: The average age at presentation was 6.1 years. The most common sites were neck (47%), cheek/parotid gland (26%), tongue (17%) and orbit (8%). Macrocystic malformations dominated the lateral neck, while microcystic malformations were predominantly localized in the tongue and floor of mouth. Macrocystic malformations (mean CDS 9.44) were associated with significantly better CDS than microcystic (mean CDS 7.11) and mixed (mean CDS 5.71) malformations (p < 0.001). LM in stage V according to de Serres had the lowest values (mean CDS: 4.26). The most common therapeutic procedures were conventional surgical (partial) resection, laser therapy and sclerotherapy with OK-432. CONCLUSIONS: There is an association between malformation type, location according to de Serres and CDS in children with LM of the head and neck. Patients with microcystic and mixed malformations in stage V had lowest CDS levels.

Sirolimus treatment for paediatric head and neck lymphatic malformations: a systematic review.

PURPOSE: This PRISMA-compliant systematic review aimed to assess risks and benefits of sirolimus treatment for paediatric lymphatic malformations by focusing not only on treatment efficacy but also on possible treatment-related adverse events, and treatment combinations with other techniques. METHODS: Search criteria were applied to MEDLINE, Embase, Web of Science, Scopus, Cochrane Library, and ClinicalTrials.gov databases and included all studies published up to March 2022 reporting paediatric lymphatic malformations treated with sirolimus. We selected all original studies that included treatment outcomes. After the removal of duplicates, selection of abstracts and full-text articles, and quality assessment, we reviewed eligible articles for patient demographics, lymphatic malformation type, size or stage, site, clinical response rates, sirolimus administration route and dose, related adverse events, follow-up time, and concurrent treatments. RESULTS: Among 153 unique citations, 19 studies were considered eligible, with reported treatment data for 97 paediatric patients. Most studies (n = 9) were case reports. Clinical response was described for 89 patients, in whom 94 mild-to-moderate adverse events were reported. The most frequently administered treatment regimen was oral sirolimus 0.8 mg/m2 twice a day, with the aim of achieving a blood concentration of 10-15 ng/mL. CONCLUSION: Despite promising results for sirolimus treatment in lymphatic malformation, the efficacy and safety profile of remains unclear due to the lack of high-quality studies. Systematic reporting of known side effects, especially in younger children, should assist clinicians in minimising treatment-associated risks. At the same time, we advocate for prospective multicentre studies with minimum reporting standards to facilitate improved candidate selection.

Two-Year Outcomes of Transcutaneous Non-Image Guided Bleomycin Sclerotherapy in Conjunctival Lymphatic Malformations: A Protocol-Based Management in 16 Eyes.

OBJECTIVES: To study the efficacy and the 2-year outcomes of treating conjunctival lymphatic malformations (LM) with protocol-based bleomycin sclerotherapy. METHODS: A retrospective interventional study of 16 eyes with conjunctival LM treated with bleomycin sclerotherapy between December 2016 and 2019. A clinical resolution was assessed as poor (less than 25% decrease in size), fair (25%-50% decrease in size), good (50%-75% decrease in size), excellent (more than 75% decrease in size), and complete resolution. RESULTS: Mean age at presentation was 18 ± 13.09 (15 years, 3 to 59 years) years. The conjunctival component was classified based on clinical appearance as conjunctival mass (12) and microcystic LM (4). Mean clock hours of involvement were 3.32 ± 5.29 clock hours (4, 2-9 clock hours). An average per session dose of 1.8 ± 0.3 IU (median 2 IU, range 1-2 IU) and a cumulative dose of 3 ± 1.5 IU (3, 1-6 IU) of bleomycin were injected over an average of 1.6 ± 0.7 (median 2, range 1-3) treatment sessions per patient. Excellent response was observed in 11 (69%) cases. A residual lesion requiring surgical debulking was noted in 1 case. Recurrence was noted in 2 (13%) cases one of which was treated with repeat sclerotherapy resulting in complete resolution. Adverse reactions included restricted extraocular motility in extreme gaze in 2 eyes (13%). Sustained tumor resolution was observed over a mean follow-up of 29.24 + 9.45 months (24, 24-38 months). CONCLUSIONS: Bleomycin sclerotherapy gives excellent response in conjunctival LMs and is an effective first-line therapy in these cases.

[A case of lymphatic vessel abnormality with chylous pneumonia].

Chylous pneumonia is a rare respiratory disease. The main clinical manifestation is coughing up chylous sputum with a variety of causes which can be clarified by lymphangiography. The lack of understanding of the disease, and infrequent lymphangiography have led to a high rate of misdiagnosis and missed diagnosis. Here, we reported a case of bronchial lymphatic fistula caused by lymphatic abnormality that led to the diagnosis and treatment of chylous pneumonia, with the aim of improving clinicians' understanding of this disease.

[Lymphangioma of the scrotum].

INTRODUCTION: Lymphangioma (lymphatic malformation) is a congenital malformation of lymphatic vessels. According to the classification of the International Society for the Study of the Vascular Anomalies, there are macrocystic, microcystic and mixed types of lymphatic malformations. The typical location of the lymphangiomas is the area of large lymphatic collectors (head, neck, axillary areas), while the scrotum is not frequently affected. AIM: To present a rare clinical case of lymphatic malformation of the scrotum with successful minimally invasive treatment (sclerotherapy). MATERIALS AND METHODS: A clinical observation of a 12-year-old child with a diagnosis of "Lymphatic malformation of the scrotum" is presented. From the age of 4, there was a large lesion in the left half of the scrotum. In other clinic, a surgical removal with a diagnosis of "left-sided inguinal hernia", "spermatic cord hydrocele", "isolated left-sided hydrocele" was performed. However, there was a recurrence after the procedure. When contacting the Clinic of pediatrics and pediatric surgery, scrotal lymphangioma was suspected. The diagnosis was confirmed by magnetic resonance imaging. The patient underwent minimally invasive sclerotherapy using the drug "Haemoblock". After 6 months of follow-up, no relapse was seen. CONCLUSION: Lymphangioma (lymphatic malformation) of the scrotum is a rare urological pathology that requires specific diagnosis, in-depth differential diagnosis and treatment by a multidisciplinary team of doctors, including a specialist in the treatment of vascular pathology.