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.

Topical Tacrolimus 0.1% for treatment of cutaneous microcystic lymphatic malformations.

Microcystic lymphatic malformations as described in the international literature form a subgroup of low-flow congenital vascular malformations (VM) resulting from irregular embryological development. Microcystic lesions normally manifest as an accumulation of lymph- and blood-filled vesicles that, when externalized, cause skin maceration with consequent pain and potential infection resulting in the impairment of the patient's quality of life. There is no consensus on a standardized algorithm nor clear guidelines for successful treatment of this type of lymphatic malformation, and treatment options employed often result in ambivalent and transient outcomes with a high rate of recurrence. The topical formulation of tacrolimus is a well-known FDAapproved anti-T cell agent that was recently identified as a potent activator of ALK1, which is involved in several processes and functions including angiogenesis. We investigated if topical administration of tacrolimus may be an effective therapy for directly targeting cutaneous microcystic lymphatic malformations as a complement to systemic treatment. The study enrolled four patients with cutaneous microcystic lymphatic malformations: three male (ages: 13,15,18) and one female (age: 30). Two of the patients presented lesions on their backs, one patient on the left hand and one on the left lower limb. All four patients received treatment with topical tacrolimus 0.1% twice a day for 10 weeks on a previously selected area for application. Weekly clinical follow-ups were conducted along with close physician-patient contact. All patients displayed a satisfactory response after treatment. Lymphorrhea and bleeding were stopped in all cases and the esthetic aspect of lesions improved in two patients. To date, all patients presented no clinically significant changes to the size or extension of the lesion. Topical tacrolimus treatment is a promising and reasonable option for microcystic lymphatic malformations. Our results encourage further exploration in larger populations with the consideration that it is a safe and effective alternative or complementary therapy to systemic treatment.

Histopathological evaluation of the effectiveness of oral Eppikajutsuto treatment for lymphatic malformation.

BACKGROUND: Lymphatic malformation (LM) is a congenital disease caused by lymphatic vessel malformation. Although standard therapies for LMs are sclerotherapy and/or surgical excision, a new therapy using Japanese herbal medicine Eppikajutsuto (TJ-28) has been recently reported as clinically effective. We aimed to experimentally confirm the therapeutic effectiveness of TJ-28 for LMs. METHODS: LM lesions were generated in the mesentery and peritoneum of mice by intraperitoneal injection of Freund's incomplete adjuvant. Mice with LMs were treated by gavage or dietary administration of TJ-28 for 2 months. Formalin-fixed paraffin-embedded tissue sections of mesentery and peritoneum tissues were histologically and immunohistochemically examined by focusing on lymph nodes and perinodal lymph vessels. RESULTS: Multiple Freund's incomplete adjuvant-associated foreign-body granulomas were formed in the mesentery and peritoneum, resulting in congestion of lymph fluid and dilatation of lymph vessels. The numbers and sizes of lymph nodes were not significantly different between TJ-28-treated and control groups. However, the luminal areas of lymphatic vessels were reduced significantly in the TJ-28 treatment group by both gavage and dietary administrations. CONCLUSION: TJ-28 conspicuously reduced congestion of lymph fluid. This is the first histopathological evaluation of LM model mice to study the effectiveness of oral TJ-28 treatment.

Treatment of superficial vascular anomalies with topical sirolimus: A multicenter case series.

BACKGROUND: Systemic sirolimus (rapamycin) has recently been found effective in treating complex vascular anomalies by reducing the size and associated complications. Many vascular anomalies have a cutaneous component, and thus, we sought to determine whether topical administration of sirolimus may be an effective therapy, as data on the use of topical sirolimus are limited. OBJECTIVE: We reviewed the efficacy and tolerability of topical formulations of sirolimus in the treatment of various simple and combined vascular malformations and tumors. METHODS: Eighteen patients with any vascular anomaly treated exclusively with topical sirolimus were retrospectively reviewed. RESULTS: Eleven patients had combined venous lymphatic malformations, three had tufted angiomas, two had a lymphatic malformation, one had a venous malformation, and one had a verrucous venous malformation. All (100%) patients reported some degree of improvement and 50% of patients reported marked improvement in one or more symptoms, most commonly blebs and lymphatic drainage, and bleeding. LIMITATIONS: The retrospective nature, small number of patients, and differences in topical preparations limit the broad application of the results. CONCLUSION: Topical sirolimus appears to be a safe and useful non-invasive therapy that is well-tolerated in the treatment of the cutaneous portion of a variety of vascular anomalies.

A single institution experience of Eppikajutsuto for the treatment of lymphatic malformations in children.

BACKGROUND: Eppikajutsuto (TJ-28) is an herbal medicine recently reported to be effective in treating lymphatic malformations (LMs). We report our experience concerning the clinical efficacy of TJ-28 for LMs. METHODS: Medical records of 10 LM cases treated with TJ-28 between 2016 and 2018 were reviewed. TJ-28 was given at 0.3 g/kg/day and then increased to 0.5 if no improvement was noted after the first three months of treatment. Their clinical data were collected, and LM volume indices (depth×width×height) were measured with the first (LMVI-F) and latest (LMVI-L) imaging studies. The response rates were calculated as 1-LMVI-L / LMVI-F (%). RESULTS: The median age at the diagnosis and treatment period was 1.5 years and 17.5 months, respectively. LMs were located in the neck (six), mesenterium or retroperitoneum (three), and inguinal region (one). The median response rate was 83%, including 100% in three cases and the apparent improvement of obstructive airway symptoms in one case. One case underwent surgery for insufficient improvement, and another that showed no effect is being considered for surgery. Most of the satisfactory outcomes were demonstrated in the first six months of treatment. CONCLUSION: TJ-28 seems to be effective in treating LMs in children, especially early in treatment. LEVEL OF EVIDENCE: IV.

Zinc effect on human lymphatic malformation cells in vitro.

OBJECTIVES: Lymphatic malformations (LM) are clinically characterized by episodes of inflammatory episodes. Often, an upper respiratory illness or trauma will lead to painful swelling in the distribution of the LM. Zinc is an element involved in numerous aspects of cellular metabolism and is a common dietary supplement and cold remedy. We surmise that zinc may act as a therapeutic anti-inflammatory agent for lymphatic malformations and their cellular components. We investigate the apparent cytotoxic effect of zinc ion on lymphatic malformation cells in vitro. METHODS: Fresh surgical lymphatic malformation specimens from 10 patients were collected and processed in a laboratory. Tissues were processed and lymphatic malformation cells were isolated and grown. Immunohistochemistry and cell morphology were used to confirm LM cells. HUVEC cells were used as controls. Zinc chloride solution was added to the cells and its effect observed. RESULTS: LM cells were isolated from five of the 10 specimens. Of these, the cells of only one specimen were able to be amplified to confluence. Five specimens were contaminated. Immunohistochemical staining (CD31, D2-40, and LYVE-1) and cell morphology of our specimens were consistent with lymphatic malformation while HUVEC control cells were negative. Zinc has a cytotoxic effect on BEL isolates in vitro with no obvious effect on cell morphology or growth rate of the control HUVEC cells. When compared with the published toxic zinc concentration for most cell types in the literature (100µM total zinc in vitro), our result indicates that LM cells may have a lower tolerance to zinc (10µM total zinc in vitro). CONCLUSION: Zinc has an apparent morphological effect on lymphatic malformation cells in vitro. Compared with other cell types, LM cells have a lower tolerance to zinc. While this result looks very promising for future therapeutic use of zinc in acute lymphangitis, further studies are necessary, such as finding the IC50 of zinc for lymphatic malformation in vitro and also in vivo.