Genomic landscape of lymphatic malformations: a case series and response to the PI3Kα inhibitor alpelisib in an N-of-1 clinical trial.

Background: Lymphatic malformations (LMs) often pose treatment challenges due to a large size or a critical location that could lead to disfigurement, and there are no standardized treatment approaches for either refractory or unresectable cases. Methods: We examined the genomic landscape of a patient cohort of LMs (n = 30 cases) that underwent comprehensive genomic profiling using a large-panel next-generation sequencing assay. Immunohistochemical analyses were completed in parallel. Results: These LMs had low mutational burden with hotspot PIK3CA mutations (n = 20) and NRAS (n = 5) mutations being most frequent, and mutually exclusive. All LM cases with Kaposi sarcoma-like (kaposiform) histology had NRAS mutations. One index patient presented with subacute abdominal pain and was diagnosed with a large retroperitoneal LM harboring a somatic PIK3CA gain-of-function mutation (H1047R). The patient achieved a rapid and durable radiologic complete response, as defined in RECIST1.1, to the PI3Kα inhibitor alpelisib within the context of a personalized N-of-1 clinical trial (NCT03941782). In translational correlative studies, canonical PI3Kα pathway activation was confirmed by immunohistochemistry and human LM-derived lymphatic endothelial cells carrying an allele with an activating mutation at the same locus were sensitive to alpelisib treatment in vitro, which was demonstrated by a concentration-dependent drop in measurable impedance, an assessment of cell status. Conclusions: Our findings establish that LM patients with conventional or kaposiform histology have distinct, yet targetable, driver mutations. Funding: R.P. and W.A. are supported by awards from the Levy-Longenbaugh Fund. S.G. is supported by awards from the Hugs for Brady Foundation. This work has been funded in part by the NCI Cancer Center Support Grants (CCSG; P30) to the University of Arizona Cancer Center (CA023074), the University of New Mexico Comprehensive Cancer Center (CA118100), and the Rutgers Cancer Institute of New Jersey (CA072720). B.K.M. was supported by National Science Foundation via Graduate Research Fellowship DGE-1143953. Clinical trial number: NCT03941782.

Imatinib Treatment of Lymphangiomatosis (Generalized Lymphatic Anomaly).

Lymphangiomatosis (eg, generalized lymphatic anomaly) is an abnormal proliferation of lymphatic endothelial cells. It is often a childhood disease, but it may present in adulthood by infiltrating organs and cause obstruction, bleeding, or disruption of lymphatic flow. Pulmonary involvement may be mild or cause diffuse interstitial lung disease, airway obstruction, hemoptysis, chylothorax, chylopericardium, and culminate in respiratory failure. Treatment has been limited to surgical resection or drainage procedures because there is no accepted effective systemic therapy. This report presents a patient with lymphangiomatosis and life-threatening hemoptysis in whom positive immunostaining forc-KITsuggested upregulation of tyrosine kinase and whose disease was controlled with imatinib.

Prenatal diagnosis and outcome of lymphangiomas and its relationship with fetal chromosomal abnormalities.

OBJECTIVES: Our aim was to evaluate ultrasound findings and perinatal outcome after prenatal diagnosis of lymphangioma. METHODS: This was a retrospective case series study. We searched the archives of our ultrasound database at our center for cases with the prenatal diagnosis of the lymphangioma in the period between January 2008 and November 2014. We described maternal, fetal and perinatal variables for all cases. RESULTS: Nine fetuses with lymphangioma were identified. All cases were diagnosed during the second and third trimesters with the average gestational age of 22.6 ± 3.9 weeks. The average diameter of lymphangioma was 55.4 ± 20.1 mm at the time of diagnosis. Five fetuses (55.6%) had lymphangioma on the neck, and four fetuses (44.4%) had lymphangioma on other localizations. Normal fetal karyotype was detected in all cases. There were a total of six live births, one intrauterine death and two medical terminations of pregnancy following the diagnosis of lymphangioma. No abnormal Doppler finding or hydrops were detected in the antenatal follow-up of remaining six cases. CONCLUSION: The risk of chromosomal abnormalities is very low in pregnancies with isolated lymphangioma. The outcome of pregnancies with lymphangioma is generally favorable and prognosis depends on their locations and size.

Enlarging cystic lymphangioma of the mediastinum in an adult: is this a neoplastic lesion related to the recently discovered PIK3CA mutation?

Cystic lymphangioma, a lymphatic system malformation, is usually observed in infants and children and is rarely found in adults. It most commonly occurs in the cervicofacial region, followed by the axilla. Mediastinal cystic lymphangioma is rare, accounting for 1.8% of all mediastinal cysts. Herein, we present an exceedingly rare adult case of mediastinal cystic lymphangioma that had increased in size over a 5-year period. Although fluid collection might be an alternative explanation for this increase in size, this lymphangioma might harbor a neoplastic nature related to the recently discovered PIK3CA mutation.

Foetal axillary lymphangioma with ipsilateral pes equinovarus: pitfalls in sonographic differential diagnosis (axillary lymphangioma & pes equinovarus).

Lymphangiomas are rare congenital malformations of the lymphatic system. Despite the benign histology, they are likely to grow rapidly and invade the surrounding tissues. In contrast to the cystic hygromas, lymphangiomas at the axillary region tend to have normal karyotype. However, associated hydrops makes the prognosis poor. Due to isolated few cases in the literature, the true incidence of foetal axillary lymphangiomas is not known. We present here a pre-natal ultrasonographic diagnosis of a 15-week foetus with rapidly growing axillary lymphangioma with ipsilateral foot abnormality which had normal karyotype.

Pediatric vascular malformations: pathophysiology, diagnosis, and the role of interventional radiology.

The Mulliken and Glowacki classification (1982) differentiated vascular anomalies into two groups based on their endothelial characteristics: hemangiomas and vascular malformations. Vascular anomalies are localized defects of the vasculature that affect a limited number of vessels in a restricted area of the body. These defects are secondary to errors in vascular morphogenesis. Depending on the type of vessel involved, the vascular malformation group was subdivided into high-flow (such as arteriovenous malformation and arteriovenous fistula) and low-flow lesions (such as venous and lymphatic malformations). Depending on the type of lesion, the location and degree of involvement and the clinical effect, different types of treatment would be required. For the purpose of this review, we concentrate solely on vascular malformations: the clinical features, genetics, diagnosis, and current treatment options.

Familial renal retroperitoneal lymphangiomatosis: personal experience and review of literature.

Lymphangiomatosis of the kidneys and perirenal-retroperitoneal tissues is a rare disease of unknown etiology. We present two cases affecting members of the same family, supporting the familial nature of the disease. The natural history and related urological and systematic complications of the disease during a long-term follow-up are highlighted, while a comprehensive literature review is presented.

Diagnóstico prenatal de un hemangioma occipital de rápida involución / Prenatal diagnosis of a occipital rapidly involuting hemangioma

El hemangioma occipital es, tras los linfangiomas, el tipode tumoración más frecuente en cabeza y cuello. Su diagnósticoecográfico suele establecerse en el tercer trimestre o finalesdel segundo trimestre siendo útil la resonancia magnética(RM) prenatal para la confirmación del mismo. Posnatalmente,la gran mayoría de los casos regresan espontáneamente si bienpueden persistir y complicarse requiriendo exéresis quirúrgica.Presentamos el caso del hemangioma fetal de involuciónrápida (RICH, Rapidly Involuting Congenital Hemangioma) anivel occipital diagnosticado por ecografía en el tercer trimestrede gestación así como una revisión de la literaturadestacando los puntos clave para su diagnóstico diferencial,manejo prenatal, conducta obstétrica y tratamiento posnatal(AU)

Occipital hemangioma is one of the most frequentfetal head and neck tumors, second only to lymphangiomas.Diagnose is usually established in the third or inthe late second trimester of pregnancy. Prenatal MRIallowsdiagnosis confirmation. Vast majority of fetal hemangiomasregress spontaneously in the first year afterdelivery. However, persistence is a possibility, and theymight present complications, such as bleeding or ulcerations,in which case surgical treatment is warranted.We report a case of rapidly involuting congenitalhemangioma (RICH) in the occipital region of fetal craniumdiagnosed on a routine third timester fetal ultrasoundscan. We also present a review of available literature,outlining the key points to differential diagnosis,prenatal, obstetric and postnatal management(AU)

Congenital lymphatic malformations.

"Vascular anomalies" represents a spectrum of vascular lesions, of unclear etiology and often with unpredictable behavior. Patients with vascular anomalies represent a unique population, in that they have focal aberrations of vascular development (in vascular malformations) or vascular proliferation (in hemangiomas). The etiology of these disorders is unclear, and likely represents a multifactorial process. Vascular anomalies are an attractive model for the study of human disorders of vasculogenesis (development of the vasculature) and angiogenesis (new vessel growth from existing vessels).

TIE2 gain-of-function mutation in a patient with pancreatic lymphangioma associated with blue rubber-bleb nevus syndrome: report of a case.

Abdominal lymphangioma is a rare tumor in adults. The most common location is the mesentery, but this tumor occasionally develops in the pancreas. We report a case of pancreatic lymphangioma associated with blue rubber-bleb nevus syndrome (BRBNS) in a Japanese woman. The pancreatic lymphangioma spread extensively throughout the retroperitoneum without causing any symptoms for more than 4 years after its histological diagnosis by laparoscopic biopsy. Multiple hemangiomas were also seen in the mucous membranes and on the skin. The hemangiomatosis was segregated in the dominant fashion in her family, and a germ-line gain-of-function mutation (Arg849Trp) in TIE2 gene was confirmed. To our knowledge, this is the first report of pancreatic lymphangioma occurring in association with BRBNS in a patient with genetic alteration. We describe the clinical features of this case and discuss a possible correlation between these two uncommon conditions.

Management of lymphatic malformations.

PURPOSE OF REVIEW: Innovative otolaryngologists, plastic surgeons, craniofacial surgeons, pediatric surgeons, radiologists, anesthesiologists, neonatologists, obstetricians, and scientists have continued to advance our understanding of the etiology, diagnosis, and treatment of lymphatic malformations. This article reviews the publications over the past 2 years with respect to these advances. RECENT FINDINGS: Fast-sequence MRI limits motion artifacts and allows prenatal MR to be used as a complementary study to ultrasound in the evaluation of large congenital neck masses. Three-dimensional ultrasonography may also be helpful in evaluating prenatal lymphatic malformations. Fluorescence in situ hybridization techniques can be used to evaluate lymphatic malformations for prenatal chromosomal analysis with emphasis on chromosomes 13, 18, 21, X, and Y. The sclerosing agent OK-432 is effective for macrocystic lymphatic malformations but showed less promise for microcystic lesions, mixed lesions, and lesions outside the head and neck region. Somnoplasty shows promise for reduction of tongue lymphatic malformations. Surgical excision, staged when necessary, continues to be integral to management in many cases. SUMMARY: Basic science research has furthered understanding of lymphatic malformations. Clinical research has expanded and refined our diagnostic and therapeutic options for patients with these lesions. Further identification of genes selectively expressed by lymphatic endothelium should facilitate identification of usable vascular markers that can enable analysis of the underlying biology, physiology, pathology, and treatment of the lymphatic system and its malformations.

Familial multiple mesothelial cysts of the spleen.

A 5-month-old boy who was diagnosed as having hydrops fetalis at 25 weeks' gestation had severe ascites of unknown origin. At the age 12 months, ultrasonography and computed tomography showed multiple cysts in the spleen that were increasing in size rapidly. Splenectomy resulted in complete disappearance of the ascites. These cysts were diagnosed as mesothelial cysts because the cell lining of the splenic cysts stained positively with alcian blue and cytokeratin. The boy's mother had undergone splenectomy for splenic and retroperitoneal lymphangiomas at 4 years of age. Histological reevaluation showed that the lining of her splenic cysts had the same mesothelial components as her son's. Their chromosomal assay showed normal karyotypes. Mesothelial cyst of the spleen appears similar to splenic lymphangioma morphologically; however, bleomycin and OK-432 were not effective. Familial splenic mesothelial (epidermoid) cysts have been reported in three sets of siblings, but this is the first report of their occurrence in mother and son.

Expression of the fms-like tyrosine kinase 4 gene becomes restricted to lymphatic endothelium during development.

We have recently cloned the human fms-like tyrosine kinase 4 gene FLT4, whose protein product is related to two vascular endothelial growth factor receptors FLT1 and KDR/FLK1. Here the expression of FLT4 has been analyzed by in situ hybridization during mouse embryogenesis and in adult human tissues. The FLT4 mRNA signals first became detectable in the angioblasts of head mesenchyme, the cardinal vein, and extraembryonally in the allantois of 8.5-day postcoitus (p.c.) embryos. In 12.5-day p.c. embryos, the FLT4 signal decorated developing venous and presumptive lymphatic endothelia, but arterial endothelia were negative. During later stages of development, FLT4 mRNA became restricted to vascular plexuses devoid of red cells, representing developing lymphatic vessels. Only the lymphatic endothelia and some high endothelial venules expressed FLT4 mRNA in adult human tissues. Increased expression occurred in lymphatic sinuses in metastatic lymph nodes and in lymphangioma. Our results suggest that FLT4 is a marker for lymphatic vessels and some high endothelial venules in human adult tissues. They also support the theory on the venous origin of lymphatic vessels.

Trisomy 4 in a fetus with cyclopia and other anomalies.

We report on an 18-week fetus with cyclopia, alobar holoprosencephaly, complex congenital heart defect, anal atresia, oligosyndactyly, cystic hygroma, and skeletal abnormalities with trisomy 4. Structural anomalies were detected on routine ultrasound of the pregnancy of a 17-year-old G3 P1 TAB1 woman with sickle cell trait. Trisomy 4 conceptuses usually miscarry in the first trimester. We are aware of no other reports of a fetus with trisomy 4 and cyclopia. Causal association of chromosome abnormalities and holoprosencephaly sequence may be more apparent in embryos and early fetuses than term fetuses because of poor viability of affected conceptuses.

Unusual lymphangioma observed prenatally in a 45,X fetus.

We present a case of a large frontal lesion, suspected on antenatal ultrasound to be a cephalocele. The cardiac anatomy was abnormal and fetal blood sampling showed a 45,X chromosome constitution. Postmortem examination proved this to be a lymphangioma and confirmed the presence of a cardiac defect. We suggest that this lymphangioma represents an unusual manifestation of monosomy X and discuss the importance of doing chromosome analysis in the presence of such a lesion which is of similar appearance as a cephalocele.