Kasabach-Merritt phenomenon: a report of 11 cases from a single institution

Analysis of angiographic characteristics of kaposiform hemangioendothelioma and investigation of the value of transcatheter arterial embolization therapy

BACKGROUND

This study aimed to analyze the angiographic characteristics of kaposiform hemangioendothelioma (KHE) and investigate the value of transcatheter arterial embolization (TAE) therapy.

METHODS

The clinical data of infants diagnosed with KHE at the department from June 2013 to June 2020 were retrospectively analyzed. Of these, 34 infants received TAE therapy. The efficacy of the treatment was evaluated 4 weeks after the therapy. The angiographic characteristics were analyzed by comparing them with the angiographic characteristics of infantile hemangioma (IH), and the times of TAE therapy and the platelet level after each TAE therapy in infants with KHE were summarized.

RESULTS

The present study showed that the capillary blush of KHE was irregular with an obscure boundary and nonuniform distribution. Many fine feeding arteries were present. The diameter of the feeding arteries was disproportionate to the volume of the tumor blush. The normal arteries were usually embedded in the tumor blush. The angiography of common IH in infants also showed tumor blush, but it was usually round with a clear boundary and uniform staining, and was distributed on 1 side of the normal arterial trunk. The infants with KHE received TAE therapy for 2 to 5 times/case, with a total of 104.0 times, with an average of 3.1±0.8/case. Among which, the platelets continued to decline for 9 times after TAE therapy and the platelets increased to ≥100×10⁹/L in 7.8±3.2 days for 95 times after TAE therapy, The average relapse time was 30.0±15.9 days.

CONCLUSIONS

The feeding arteries of KHE were numerous and fine and were not easily embolized. The application of TAE may rapidly improve the platelet level, but the long-term effect is poor.

Comparison of efficacy and safety of corticosteroid and vincristine in treating kaposiform hemangioendothelioma and tufted angioma: A multicenter prospective randomized controlled clinical trial

Kaposiform haemangioendothelioma (KHE) and tufted angioma (TA) are rare vascular tumors that can cause life-threatening Kasabach-Merritt phenomenon. No evidence-based treatment strategies have yet been established, and its management is still a challenge. The purpose of this multicenter prospective randomized controlled study was to evaluate and compare the efficacy of corticosteroid and vincristine (VCR) in the treatment of KHE and TA. All patients with KHE/TA who met the diagnostic criteria were consecutively recruited. The patients were randomized into a methylprednisolone (MP) group and a VCR group. The primary outcome was the single main parameter effective rate and overall effective rate of corticosteroid and VCR over 1 month after treatment. The single main parameters included platelets, fibrinogen, tumor size, texture, and appearance. From May 2016 to April 2018, a total of 59 patients completed the clinical trial, including 29 in the MP group and 30 in the VCR group. The results showed that VCR was superior to corticosteroid in the improvement of platelet (80.0% vs 44.0%, P = 0.019) and tumor texture (68.9% vs 30.8%, P = 0.007). Although the efficacy of VCR on fibrinogen (23.3% vs 20.7%, P = 1.000), tumor size (23.3% vs 13.8%, P = 0.273), and appearance (65.5% vs 46.2%, P = 0.120) was higher than that of corticosteroid, there was no significant difference (P > 0.05). Meanwhile, the overall effective rate of VCR was higher than that of corticosteroid (56.7% vs 31.0%), but the difference was also not statistically significant (P = 0.067). In conclusion, the therapeutic effect of VCR was significantly better than that of corticosteroid with regard to treating thrombocytopenia and tumor texture. We recommend that VCR could be an option for first-line treatment in KHE/TA patients.

Immunohistochemical Analysis of mTOR Pathway-Related Proteins in Kaposiform Hemangioendothelioma

BACKGROUND

Mammalian target of rapamycin (mTOR) inhibitors have been shown to have excellent effects in the management of kaposiform hemangioendothelioma (KHE); however, the mechanism of action is unclear. This study identified the expressions of mTOR pathway-related proteins in different vascular tumors to provide insight into the pathogenesis of KHE.

METHODS

We retrospectively reviewed the pathologic specimens of 30 patients (KHE, 15; tufted angioma [TA], 5; infantile hemangioma [IH], 5; and lymphatic malformation [LM], 5). The immunohistochemical expression of mTOR-related proteins tuberous sclerosis complex 2 (TSC2), phosphatase and tensin homologue (PTEN), phosphorylated eukaryotic translation initiation factor 4E binding protein 1 (p-4EBP1), phosphorylated mTOR (p-mTOR), and phosphorylated ribosomal protein S6 kinase B1 (p-P70S6K) were analyzed using Image-Pro Plus software. KHE had the following pattern of expression in the spindle vascular endothelial cells: TSC2 (-); PTEN (-); p-4EBP1 (+); p-mTOR (+); and p-P70S6K (+).

RESULTS

All 3 patients treated with sirolimus had good responses. The TA results were similar to KHE with no significant differences (p-4EBP1: p = 0.0687; p-mTOR: p = 0.0832). The expressions of TSC2, PTEN, p-4EBP1, p-mTOR, and p-P70S6K were negative or weakly positive in IH with a statistically significant difference compared to KHE (p-4EBP1: p < 0.001; p-mTOR: p < 0.001; p-P70S6K: p < 0.001). LM had no significant differences when compared to KHE.

CONCLUSIONS

The absence of TSC2 and PTEN caused abnormal activation of the mTOR signaling pathway and may be involved in the pathogenesis of KHE. The expression of mTOR-related proteins in TA and LM was similar to KHE, unlike IH. The KHE pattern of expression [PTEN (-), TSC2 (-), p-mTOR (+), p-P70S6K (+), and p-4EBP1 (+)] suggested that sirolimus may be a good therapeutic choice.

Population pharmacokinetics of sirolimus in pediatric patients with kaposiform hemangioendothelioma: A retrospective study

Numerous studies have established population pharmacokinetics (PPK) models of sirolimus in various populations. However, a PPK model of sirolimus in Chinese patients with pediatric kaposiform hemangioendothelioma (PKHE) has yet to be established; therefore, this was the purpose of the present study. The present study was a retrospective analysis that utilized the trough concentration data obtained from traditional therapeutic drug monitoring-based dose adjustments. A total of 17 Chinese patients with PKHE from a real-world study were characterized by non-linear mixed-effects modeling. The impact of demographic features, biological characteristics and concomitant medications was assessed. The developed final model was evaluated via bootstrap and a prediction-corrected visual predictive check. A one-compartment model with first-order absorption and elimination was used for modeling of data for PKHE. The typical values of apparent oral clearance (CL/F) and apparent volume of distribution (V/F) in the final model were 3.19 l/h and 165 liters, respectively. Age, alanine transaminase levels and sex were included as significant covariates for CL/F, while the duration of treatment with sirolimus was a significant covariate for V/F. In conclusion, the present study developed and validated the first sirolimus PPK model for Chinese patients with PKHE.

First Intracardiac Kaposiform Hemangioendothelioma in an Infant Resolved With Sirolimus: A Case Report

INTRODUCTION

Kaposiform hemangioendothelioma (KHE) is a rare and aggressive vascular tumor that can be associated with a consumptive coagulopathy and thrombocytopenia (Kasabach-Merritt phenomenon). Only one case of an intracardiac KHE has been reported which was treated with surgical excision and then expectant management.

CASE PRESENTATION

We present a patient with an intracardiac KHE which presented as a large mass surrounding the atria, pulmonary veins, superior vena cava, and infiltrating the atrial septum with moderate compression of the superior vena cava and mild compression of the pulmonary veins. This tumor clinically presented as persistent tachypnea and was unresponsive to conventional therapy with vincristine and steroids but responded dramatically to Sirolimus with almost complete regression on follow-up.

CONCLUSIONS

None of the current treatments for KHE, alone or in combination therapy have been found to be effective in a uniform or reproducible manner. Well designed, preferably randomized trials are required for a better understanding of the appropriate dosage and duration as well as response to treatment and a consensus of first and second line therapies.

Sirolimus as initial therapy for kaposiform hemangioendothelioma and tufted angioma

BACKGROUND

Sirolimus has been used to manage various complex vascular anomalies. Kaposiform hemangioendothelioma and tufted angioma may develop Kasabach-Merritt phenomenon in infancy.

METHODS

We retrospectively reviewed the clinical and laboratory data of eight patients with kaposiform hemangioendothelioma and tufted angioma who were initially treated using oral sirolimus in our center, including six with Kasabach-Merritt phenomenon.

RESULTS

Five girls and three boys seen between September 2012 and March 2015 were included. Age at initiation of sirolimus ranged from 30 days to 14 weeks (mean±SD 8.6 ± 3.5 weeks). Six of these eight patients had kaposiform hemangioendothelioma, and two had a tufted angioma. Platelet count before start of oral sirolimus ranged from 5 × 10⁹ /L to 189 × 10⁹ /L ((78.8 ± 65.2)×10⁹ /L) and fibrinogen level from 68 to 215 mg/dL (123.1 ± 50.5 mg/dL). All patients received standard doses of sirolimus (0.05 mg/kg orally, twice daily) as initial therapy. All patients with thrombocytopenia or hypofibrinogenemia reached a normal platelet count and a normal fibrinogen level within 3 to 4 weeks after sirolimus treatment. Length of treatment ranged from 12 to 79 weeks (39.9 ± 15.3 weeks). Two patients developed grade 2 oral mucositis during treatment.

CONCLUSION

Sirolimus as first-line therapy shows great promise in the treatment of kaposiform hemangioendothelioma and tufted angioma.

Successful Management of Kaposiform Hemangioendothelioma with Long-Term Sirolimus Treatment: a Case Report and Review of the Literature

Background

Kaposiform Hemangioendothelioma (KHE) is a rare vascular tumour of the infancy and the first decade of life. It is locally aggressive and potentially life threatening when associated with consumptive coagulopathy, known as Kasabach-Merritt syndrome (KMS). No consensus or guideline for the therapy has been reached because of the lack of prospective trials, and the different standard care suggestions are based on retrospective case series.

Case report

We report the case of a 9-month-old male with KHE and KMS in which the initial response, obtained with prednisone and vincristine, was subsequently consolidated and strengthened by long-term treatment with sirolimus, a mTOR inhibitor. A summary of the published data is presented as well.

Conclusions

The inhibition of mTOR pathway represents the most important therapeutic innovation introduced in the last few years for KHE. Our case shows the effectiveness and good tolerance of long-term therapy with sirolimus.

Successful management of steroid-resistant vascular tumors associated with the Kasabach-Merritt phenomenon using sirolimus

Vascular tumors associated with Kasabach-Merritt phenomenon (KMP) are life-threatening and the mortality is as high as 10-30%. Steroids are considered the primary choice for drug therapy. However, there are many steroid-resistant cases. In the present study, analyzed data are presented to support the use of sirolimus in clinical practise for the treatment of corticosteroid-resistant vascular tumors with KMP in eight infants between June 2015 and April 2017 in a single hospital. The time to initial response was 6.8 ± 2.7 days. The average stabilization time for the platelet count was 19.1 ± 8.5 days. At the time of publication, the average duration of sirolimus treatment was 14.1 ± 4.0 months, and the average time for sirolimus treatment as a single agent was 12.6 ± 4.2 months. The side-effects were tolerable and included oral ulcer, fever, pain, skin rash and transient ascension of serum transaminase and cholesterol. Our study indicated that sirolimus therapy is an effective and safe method for the treatment of corticosteroid resistant vascular tumors associated with KMP in infants.

Artesunate inhibits proliferation and invasion of mouse hemangioendothelioma cells in vitro and of tumor growth in vivo

Artesunate has been demonstrated to be a novel potential antitumor agent in numerous studies. However, its efficacy in infantile hemangioma is unknown. The aim of the present study was to investigate the role of artesunate in the control of vascular tumor biological behavior and molecular mechanism using mouse hemangioendothelioma endothelial (EOMA) cells and a nude mouse model. Cell viability, apoptosis and invasion were determined by an MTT assay, flow cytometric analysis and Transwell invasion assay, respectively. Reverse transcription-quantitative polymerase chain reaction and western blotting were utilized to examine the expression of genes and proteins. Inoculated EOMA cells were injected into the subcutaneous tissues of nude mice to observe the effect of artesunate therapy on the vascular tumor, an effect that was similar to that of pingyangmycin (PYM). It was identified that artesunate treatment (0-600 µg/ml) inhibited cell growth in a time- and dose-dependent manner. Artesunate at 300 µg/ml significantly reduced the proliferation and invasion of EOMA cells, and significantly decreased the expression of vascular endothelial growth factor (VEGF)-A, VEGFR-1, VEGFR-2 and hypoxia inducible factor-1α over time; caspase-3 was simultaneously upregulated in vitro. Artesunate significantly inhibited tumor growth, and the curative effect was similar to that observed with PYM in vivo. It was concluded that artesunate could effectively inhibit the growth of vascular tumors, and thus could be a novel drug candidate for the treatment of infantile hemangioma.

Excellent outcome of medical treatment for Kasabach-Merritt syndrome: a single-center experience

Background

Kasabach-Merritt syndrome (KMS) is a rare but life-threatening illness. The purpose of this study is to report our single-center experience with KMS.

Methods

We reviewed the medical records of 13 patients who were diagnosed with KMS between 1997 and 2012 at Samsung Medical Center. Treatment response was defined as follows: 1) hematologic complete response (HCR) – platelet count >130×10⁹/L without transfusion; 2) clinical complete response (CCR) – complete tumor disappearance or small residual vascular tumor displaying lack of proliferation for at least 6 months after treatment discontinuation.

Results

Participants included 7 male and 6 female patients. The median initial hemoglobin levels and platelet counts were 9.7 g/dL (range, 6.6–11.6 g/dL) and 11×10⁹/L (range, 3–38×10⁹/L), respectively. Twelve patients received corticosteroid and interferon-alpha as initial treatment, and the remaining patient received propranolol instead of corticosteroid. Two patients with unsatisfactory response to the initial treatment received weekly vincristine. Successful discontinuation of medication was possible at a median of 301 days (range, 137–579) in all patients except one who was lost to follow-up. The median times to achieve HCR and CCR were 157 days and 332 days, respectively. The probabilities of achieving HCR and CCR were 77% and 54% at 1 year, and 88% and 86% at 2.5 years, respectively.

Conclusion

The prognosis of KMS in our cohort was excellent. Our data suggest that individualized treatment adaptation according to response may be very important for the successful treatment of patients with KMS.

Clinical Outcomes for Systemic Corticosteroids Versus Vincristine in Treating Kaposiform Hemangioendothelioma and Tufted Angioma

A meta-analysis was performed to evaluate the efficacy and safety of systemic corticosteroids versus those of vincristine in the treatment of kaposiform hemangioendothelioma (KHE) and tufted angioma (TA).A literature search of PubMed, Embase, and Web of Science was performed for clinical studies on systemic corticosteroid versus vincristine therapies in treating KHE/TA. Pooled relative risks (RRs) and response rate with 95% confidence intervals (CIs) were used to measure outcomes. Heterogeneity, subgroup analysis, sensitivity analysis, and publication bias analysis were performed for result evaluation.Thirteen studies, comprising 344 participants, were used in the analysis. Vincristine therapy was found to be relatively more effective than systemic corticosteroids (RRs = 0.45, 95%CI: 0.35-0.58). The result of pooled adverse reactions response rate for systemic corticosteroids was 0.31 (95%CI, 0.18-0.43), significantly higher than that for vincristine, which was 0.12 (95%CI, 0.06-0.19). In subgroup analyses, factors including mean age and race of patients, and period of follow-up were examined as possible sources of heterogeneity.This is the first meta-analysis estimating the clinical outcomes of systemic corticosteroids in comparison with those of vincristine in the treatment of KHE/TA. The results showed that vincristine was considerably more effective with lower complication rates than systemic corticosteroids; thus, vincristine could be suggested as the first-line therapy for KHE/TA.

Mesenchymal tumours of the mediastinum--part II

This is the second part of a two-part review on soft tissue tumours which may be encountered in the mediastinum. This review is based on the 2013 WHO classification of soft tissue tumours and the 2015 WHO classification of tumours of the lung, pleura, thymus and heart and provides an updated overview of mesenchymal tumours that have been reported in the mediastinum.

Recent advances in the pathobiology and management of Kasabach-Merritt phenomenon

Kasabach-Merritt Phenomenon (KMP) refers to the clinical constellation of thrombocytopenia, consumptive coagulopathy and purpura associated with Kaposiform haemangioedothelioma or tufted angioma, but not the more common infantile haemangioma. It shows a variable and unpredictable response to traditional pharmacological agents, such as steroids, vincristine or interferon alpha 2a or 2b. More recently, the interaction between platelets and endothelial cells and the proangiogenic phenotype that results has been recognized to underly the pathogenesis of this disorder. Recent efforts have attempted to target the platelet by using antiplatelet agents and by the withholding of platelet transfusions even in those patients who have significant thrombocytopenia and laboratory evidence of coagulopathy. Excellent response rates and prompt results have been achieved by combining antiplatelet therapy with vincristine, without the need for steroid use. This synergistic approach moves away from the conventional wisdom of treating the underlying lesion to control the coagulopathy. Sirolimus, which is directed against the PI3/AKT/mTOR downstream signalling pathway involved in lymphangiogenesis, has also shown promising results, although further study is needed.

Steroid-resistant kaposiform hemangioendothelioma: a retrospective study of 37 patients treated with vincristine and long-term follow-up

BACKGROUND

Kaposiform hemangioendothelioma (KHE) with Kasabach-Merritt phenomenon (KMP) still remains a particular and life-threatening disease. The purpose of this study was to evaluate the efficacy of vincristine (VCR) and the possibility of replacement with steroids in the treatment of steroid-resistant KHE with KMP.

PROCEDURE

We retrospectively reviewed the medical records of 37 patients with steroid-resistant KHE who were treated at the Children's Hospital of Fudan University between March 2003 and March 2013.

RESULTS

The age of initial diagnosis with KHE was between 1 day and 10 months. Eight and 29 cases were located in the superficial and deep soft tissues, respectively. Thirty-seven KHE lesions did not respond well to steroids before starting VCR treatment. Twenty-six KHE lesions achieved complete remission, with platelet counts reaching normal levels within7.6 ± 5.2 weeks after VCR treatment. The vascular tumor began to decrease in size or soften at an average of 4.9 ± 2.7 weeks. Two KHE lesions had partial responses and one remains in treatment. Eight KHE lesions had no apparent response to VCR and thus received other therapies. Twenty-eight patients have ended treatment with VCR; the average length of treatment was 31.2 ± 5.9 weeks. Side effects occurred in 48.6% of patients who received steroids, and in 11.4% of patients who received VCR treatment. The mean follow-up time was 3.5 years. No recurrences have been reported.

CONCLUSIONS

VCR appears to be a safe and effective treatment option in the management of steroid-resistant KHE with KMP, and recommended as first-choice treatment.

Successful treatment of mild pediatric kasabach-merritt phenomenon with propranolol monotherapy

Kasabach-Merritt phenomenon (KMP) is relatively rare in childhood and adolescents with high mortality rate because of its hemorrhagic complications and unresponsiveness to treatments such as corticosteroids, vincristine, intravascular embolization, and/or surgery. Propranolol, a β -adrenergic receptor blocker, has a promising efficacy against vascular tumors such as infantile hemangiomas. But limited and variable data has been reported regarding the role of propranolol in treatment of KMP. We herein reported the successful treatment of mild pediatric KMP with propranolol monotherapy in a case of a five-week-old child with kaposiform hemangioendothelioma with successful treatment of both clinical and hematologic responses. After eight months of follow-up, patient still had stable cutaneous lesion while receiving propranolol monotherapy. Regular hematologic monitoring was done in order to detect any late relapse of the disease. Six months after discontinuation of propranolol, patient has still remained free of hematologic relapse, and primary cutaneous lesion has become a pale pink, 1 cm sized skin lesion.