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

Kaposiform Hemangioendothelioma with Kasabach-Merritt Phenomenon in a Neonate - Role of Dual Therapy: A Case Report and Review of Literature

Kaposiform hemangioendothelioma (KHE) represents a rare, borderline vascular tumor with locally aggressive behavior. They are often associated with a potentially life-threatening coagulopathy known as Kasabach–Merritt phenomenon (KMP). Due to heterogeneous nature of the vascular lesion and lack of standardized treatment protocols, these patients pose a diagnostic dilemma and therapeutic challenge with morbidity and potential mortality. We report successful management of an infant with KHE and associated KMP. Difficulties encountered in diagnosis, initiation of therapy, and role of dual therapy with vincristine and steroids are discussed.

Control of Platelet CLEC-2-Mediated Activation by Receptor Clustering and Tyrosine Kinase Signaling

Platelets are blood cells responsible for vascular integrity preservation. The activation of platelet receptor C-type lectin-like receptor II-type (CLEC-2) could partially mediate the latter function. Although this receptor is considered to be of importance for hemostasis, the rate-limiting steps of CLEC-2-induced platelet activation are not clear. Here, we aimed to investigate CLEC-2-induced platelet signal transduction using computational modeling in combination with experimental approaches. We developed a stochastic multicompartmental computational model of CLEC-2 signaling. The model described platelet activation beginning with CLEC-2 receptor clustering, followed by Syk and Src family kinase phosphorylation, determined by the cluster size. Active Syk mediated linker adaptor for T cell protein phosphorylation and membrane signalosome formation, which resulted in the activation of Bruton's tyrosine kinase, phospholipase and phosphoinositide-3-kinase, calcium, and phosphoinositide signaling. The model parameters were assessed from published experimental data. Flow cytometry, total internal reflection fluorescence and confocal microscopy, and western blotting quantification of the protein phosphorylation were used for the assessment of the experimental dynamics of CLEC-2-induced platelet activation. Analysis of the model revealed that the CLEC-2 receptor clustering leading to the membrane-based signalosome formation is a critical element required for the accurate description of the experimental data. Both receptor clustering and signalosome formation are among the rate-limiting steps of CLEC-2-mediated platelet activation. In agreement with these predictions, the CLEC-2-induced platelet activation, but not activation mediated by G-protein-coupled receptors, was strongly dependent on temperature conditions and cholesterol depletion. Besides, the model predicted that CLEC-2-induced platelet activation results in cytosolic calcium spiking, which was confirmed by single-platelet total internal reflection fluorescence microscopy imaging. Our results suggest a refined picture of the platelet signal transduction network associated with CLEC-2. We show that tyrosine kinase activation is not the only rate-limiting step in CLEC-2-induced activation of platelets. Translocation of receptor-agonist complexes to the signaling region and linker adaptor for T cell signalosome formation in this region are limiting CLEC-2-induced activation as well.

Bone Marrow Langerhans Cell Histiocytosis in Association with Kasabach-Merritt Syndrome: The Difficulty of a Differential Diagnosis

Langerhans cell histiocytosis is a rare haematological disorder with variable clinical findings and a high mortality rate. On the other hand, Kasabach-Merritt syndrome is of rare onset at adult age, requiring the simultaneous presentation of vascular lesion, thrombocytopenia, and consumptive coagulopathy. We present the first reported case of both diseases in a single patient and highlight the difficulties of diagnostic. A 69-year-old woman with immune thrombocytopenic purpura underwent surgery for the removal of giant skin haemangiomas. During post-operative care, intravascular disseminated coagulopathy developed. After weeks of corticosteroids and immunosuppressive therapy with no clinical improvement, pulmonary tuberculosis was diagnosed and appropriate treatment initiated. Despite all the efforts, the patient's clinical condition kept worsening and she eventually died. An autopsy revealed bone marrow Langerhans cell histiocytosis. In this case, the patient's autoimmune background together with tuberculosis and intravascular disseminated coagulopathy masked the presentation and made the diagnosis of a rapidly progressive fatal disease very difficult.

Current concepts in ablative procedures for primary benign liver lesions: a step forward to minimize the invasiveness of treatment when deemed necessary

With increased use of medical imaging, the incidental detection of benign solid liver tumors has become more frequent. Facing with benign disease, the indications for surgery are still object of discussion in light of the stable natural course of most lesions and obvious drawbacks of any surgical intervention; therefore, in most situations, a conservative approach is recommended, and surgery is mainly reserved for those cases with persistent or worsening symptoms, or who are at risk for complications as malignant transformation. The advent of ablative techniques has widened the range of treatment options available to these patients, presenting as a valid alternative to resection in terms of safety and efficacy in selected cases, particularly in patients who are considered poor surgical candidates and with smaller lesions. This review outlines the role of percutaneous ablative methods for benign solid liver tumors that are encountered in adults, providing a per histology analysis of the existing evidence. The up-to-date strategies for management of the most common benign solid tumors are recapitulated.

Unexplained isolated acute severe thrombocytopenia after surgery for a recurrent malignant retroperitoneal tumor presenting with colon perforation: A case study of a disastrous complication

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Thrombocytopenia in cancer patients is correlated with poor prognosis.

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Drugs, sepsis, HIT, DIC, ITP are the most common causes of postoperative thrombocytopenia.

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Prompt diagnosis is essential as management varies considerably depending on etiology.

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Secondary ITP has not previously been associated with a retroperitoneal tumor.

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Kasabach-Merritt syndrome has not previously been associated with a retroperitoneal tumor.

Introduction

Tumor- or treatment- induced thrombocytopenia in solid cancer patients is common. In the postoperative setting, diagnosis of thrombocytopenia become more complex as infection, sepsis, drugs and transfusion come also into the equation.

Presentation of case

Herein, the case an otherwise-healthy 71-year-old male patient with a sizable recurrent malignant retroperitoneal tumor under pazopanib admitted with colon perforation and submitted to emergency left colectomy with end transverse colostomy is presented. Immediate postoperative period characterized by massive primary tumor growth and isolated acute severe thrombocytopenia. The patient treated with combined prednisone, IVIg and platelets transfusion along with medication discontinuation with no response.

Discussion

Sepsis-, drug- and heparin-induced thrombocytopenia, disseminated intravascular coagulopathy and secondary (sepsis-, drug-, transfusion- or tumor-induced) immune thrombocytopenia (ITP) were included in the differential diagnosis. Based on exclusion, secondary drug- or tumor-induced ITP was the most prominent diagnosis. Concomitant presentation of thrombocytopenia along with massive primary tumor growth made Kasabach-Merritt syndrome also a probable diagnosis. However, neither secondary ITP nor Kasabach-Merritt syndrome has previously been associated with a retroperitoneal tumor in the literature.

Conclusion

Although management of thrombocytopenia depends on etiology, in our patient’s case the diagnosis of secondary ITP and directed management did not result in a successful outcome.

Kaposiform hemangioendothelioma: current knowledge and future perspectives

Kaposiform hemangioendothelioma (KHE) is a rare vascular neoplasm with high morbidity and mortality. The initiating mechanism during the pathogenesis of KHE has yet to be discovered. The main pathological features of KHE are abnormal angiogenesis and lymphangiogenesis. KHEs are clinically heterogeneous and may develop into a life-threatening thrombocytopenia and consumptive coagulopathy, known as the Kasabach-Merritt phenomenon (KMP). The heterogeneity and the highly frequent occurrence of disease-related comorbidities make the management of KHE challenging. Currently, there are no medications approved by the FDA for the treatment of KHE. Multiple treatment regimens have been used with varying success, and new clinical trials are in progress. In severe patients, multiple agents with variable adjuvant therapies are given in sequence or in combination. Recent studies have demonstrated a satisfactory efficacy of sirolimus, an inhibitor of mammalian target of rapamycin, in the treatment of KHE. Novel targeted treatments based on a better understanding of the pathogenesis of KHE are needed to maximize patient outcomes and quality of life. This review summarizes the epidemiology, etiology, pathophysiology, clinical features, diagnosis and treatments of KHE. Recent new concepts and future perspectives for KHE will also be discussed.

Childhood Vascular Tumors

Vascular tumors in pediatric patients are an important entity for the clinician to recognize and correctly diagnose. They may present at birth or develop at any point during infancy, childhood, or adolescence. Most are benign, but even benign lesions may have significant morbidity without proper intervention. Malignant vascular tumors are also rarely seen in the pediatric population, and may be associated with various syndromes.

Kaposiform lymphangiomatosis and kaposiform hemangioendothelioma: similarities and differences

BACKGROUND

Kaposiform lymphangiomatosis (KLA) and kaposiform hemangioendothelioma (KHE) are rare and aggressive vascular disorders. The aim of this study was to examine the clinical features and prognosis of KLA and KHE involving the thorax.

METHODS

The clinical features, imaging and pathological findings, treatments and outcome were retrospectively reviewed for 6 patients with KLA and 7 patients with KHE involving the thorax.

RESULTS

The mean ages at the time of the presentation of signs/symptoms were 26.7 months and 4.1 months for KLA and KHE, respectively. Respiratory symptoms, pericardial and pleural effusion, thrombocytopenia and coagulopathy were common in both KLA and KHE. Diffuse lesions involving the lung and extrathoracic sites were observed in KLA but not in KHE. Histopathologically, all lesions had spindled tumor cells, which were immunoreactive for CD31 and D2-40. In KLA, the spindle cells were distributed in sparse and poorly marginated clusters, whereas the spindle cells formed more defined and confluent vascularized nodules in KHE. Unlike the refractory behavior of KLA, the majority of patients with KHE responded to medical treatments with regression of the lesion and normalization of the hematologic parameters.

CONCLUSIONS

The presenting and histological characteristics of KLA can overlap with those of KHE. The presence of diffuse vascular lesions in the mediastinum and lung with refractory thrombocytopenia and coagulopathy should suggest the diagnosis of KLA. Given the rarity and high morbidity and mortality of these disorders, the diagnostic process and therapeutic approach should include a multidisciplinary team review and consensus.

Kasabach-Merritt syndrome arising from a vascular fistula

A 58-year-old woman presented with gum bleeding, hematuria, and cutaneous ecchymoses. Left hip replacement had been performed five years prior. The overall findings of our work-up were consistent with ongoing DIC triggered by the presence of an arterio-venous left femoral fistula. The patient was treated successfully with fresh frozen plasma, the fistula was surgically repaired and a stent was placed. On the second day, bleeding had resolved and laboratory values reverted to normal. This uncommon scenario is reminiscent of the Kasabach-Merritt syndrome and well illustrates that patients with an arterio-venous fistula can sometimes present with atypical features. The Kasabach-Merritt syndrome is reported in pediatric and adult patients with giant hemangiomas and angiosarcomas. Adult cases are described also in association with hematomas and large vascular aneurysms. The underlying pathophysiology is the sequestration and consumption of platelets and clotting factors with uncontrolled formation of microthrombi within the vascular lesion. DIC and a microangiopathic hemolytic anemia can subsequently develop. Mechanistic pathways of the Kasabach-Merritt syndrome in the context of a vascular fistula are shared with the more common causes of the syndrome. We speculate that the endothelial dysfunction and injury caused by the flow shear were the pivotal triggers of the aberrant trapping of platelets, the consumptive coagulopathy, and the formation of microthrombi within the fistula. Mortality rate can be as high as up to 40%. The Kasabach-Merritt syndrome could represent the only clinical feature of an otherwise occult vascular fistula. Emergency physicians should be aware of this condition.

Vascular tumors in infants and adolescents

Malignant vascular tumors as part of the vascular anomalies spectrum are extremely rare in children and young adults. Instead, benign vascular neoplasias are frequently encountered in the pediatric patient population. While vascular malformations are congenital vascular lesions, originating from a mesenchymal stem cell defect, vascular tumors are neoplastic transformations of endothelial and other vascular cells. The appropriate differential diagnosis and nomenclature according to the classification of the International Society for the Study of Vascular Anomalies (ISSVA) is decisive to initiate correct therapy. While infantile hemangioma can be routinely diagnosed by clinical means and rarely require therapy, more rare vascular tumors are frequently difficult to diagnose, require dedicated cross-sectional imaging, and benefit from an interdisciplinary treatment approach. The focus of this review is to provide an overview over the spectrum of vascular tumors, typical imaging characteristics, and summarize treatment options including interventional radiology approaches.

Local suture ligation-assisted percutaneous sclerotherapy for Kasabach-Merritt phenomenon-associated kaposiform haemangioendothelioma

Kaposiform haemangioendotheliomas (KHEs) complicated by the Kasabach-Merritt phenomenon (KMP) are rare and severe neoplastic lesions often associated with locally aggressive disease, consumption coagulopathy and high mortality rates. Current regimens have yet to achieve a satisfactory therapeutic effect. Thus, an effective and minimally invasive approach for treating complex KHE/KMP cases is necessary for clinical management. The present case series describes patients with KHE/KMP who underwent local suture ligation-assisted percutaneous sclerotherapy to minimise surgical trauma and ensure effective treatment. Between September 2015 and September 2017, 3 consecutive patients with KHE/KMP underwent staged local suture ligation-assisted percutaneous sclerotherapy. Of these patients, 2 presented with medical histories of corticosteroid treatment with unsatisfactory outcomes. The patients underwent a stepwise synthetic serial therapy programme consisting of percutaneous sclerotherapy and adjunctive pharmacotherapy accompanied by a suture ligation procedure. Clinical, radiological, pathological and laboratory data were analysed to evaluate the outcomes of the therapy. All patients were successfully managed with the proposed procedure. Significant relief of clinical symptoms and improvements in haematological indicators were achieved. No recurrence or complications were observed during regular follow-up (4, 19 and 28 months). In conclusion, local suture ligation-assisted percutaneous sclerotherapy was demonstrated to be a safe and effective treatment for KHE/KMP, being minimally invasive, involving simple manipulation and providing a clear treatment benefit in certain cases. Further studies involving larger sample sizes are required to thoroughly evaluate the procedure, which can potentially be used as a novel therapeutic option for KHE/KMP treatment.

Kaposiform hemangioendothelioma with Kasabach-Merritt phenomenon in an infant: Successful treatment with prednisolone, vincristine, and addition of sirolimus

A full-term newborn with kaposiform hemangioendothelioma (KHE) affecting the right thigh with thrombocytopenia due to Kasabach-Merritt phenomenon (KMP) was referred to our center. After biopsy, he rapidly evolved to severe thrombocytopenia and severe coagulopathy. Standard therapy was initiated with prednisolone and vincristine. His coagulopathy worsened to life-threatening hemorrhage necessitating aggressive blood products replacement. Sirolimus was added; he became transfusion independent with no further bleeding and reduction in tumor size. Addition of sirolimus to treatment of vascular anomalies with hemostatic complications should be considered as part of early treatment for patients with KMP/KHE.

Kaposiform hemangioendothelioma without cutaneous involvement

PURPOSE

We sought to characterize the clinical features and management of patients diagnosed as Kaposiform hemangioendothelioma (KHE) without cutaneous involvement.

METHODS

The electronic patient chats at six Triple A hospitals in China were searched to find all patient diagnoses with KHE without cutaneous involvement.

RESULTS

Of 30 patients (mean age at diagnosis, 55.6 months), 17 (56.7%) were male. Fourteen (46.7%) patients were associated with Kasabach-Merritt phenomenon (KMP). Patients with KMP were significantly more likely to have lesions involving truck compared to patients without KMP (odds ratio 10.000; 95% confidence interval 1.641-60.921; P = 0.011). Other common complication included severe anemia and decreased range of motion. In the majority of cases (93.3%), the lesions were highly infiltrative and locally invasive with ill-defined margins. Histological examination was required in all patients without KMP for precise diagnosis. In all, 16 (53.3%) patients received corticosteroid treatment, 19 (63.3%) received oral sirolimus treatment, 7 (23.3%) received intravenous vincristine, and 5 (16.7%) patients used propranolol. Patients had varied responses to conventional drugs, whereas all patients receiving sirolimus treatment had better response. In all, three patients (10%) died of disease, all presented with KMP. Feature of these recalcitrant cases (death) included young age, visceral location, extensive involvement, and lack of improvement with high-dose corticosteroids.

CONCLUSIONS

Our study clearly demonstrated that KHE without cutaneous involvement could be associated with important complication, which might result in death or severe morbidity. Increased awareness of KHE without cutaneous involvement is required for early diagnosis and aggressive therapy in an attempt to prevent complication.

Development of Kasabach-Merritt phenomenon following vaccination: More than a coincidence?

Kasabach-Merritt phenomenon (KMP) occurred uniquely in patients with kaposiform hemangioendothelioma (KHE) and tufted angioma (TA). We report the clinical characteristics of two patients with KHE involving the right upper arm. The patients demonstrated rapid enlargement of the lesion with severe KMP shortly after vaccination. Sirolimus was used to treat the KHE with KMP. The patients showed a quick normalization of the platelet level. The follow-up examination revealed that the size of the mass was significantly decreased. This report raises the intriguing possibility that extrinsic factors may contribute to the development of KMP in the context of an already existing KHE.

Musculoskeletal complication in kaposiform hemangioendothelioma without Kasabach-Merritt phenomenon: clinical characteristics and management

PURPOSE

Musculoskeletal complications have been associated with kaposiform hemangioendothelioma (KHE) and can lead to disability and reduced quality of life. We aimed to determine the clinical characteristics of musculoskeletal complication in patients with KHE without Kasabach-Merritt phenomenon (KMP) in order to identify features that may aid clinicians in KHE treatment.

PATIENTS AND METHODS

We conducted a cohort study of KHE without KMP associated with musculoskeletal complication between January 2006 and February 2017 at three tertiary medical centers in China. The study included 29 nonthrombocytopenic patients with KHE and musculoskeletal complication.

RESULTS

The mean age at diagnosis of KHE was 4.5 years (range, 0.3-50.0 years). The mean follow-up was 4.1 years (range, 0.5-9.0 years). In most cases (72.4%), decreased range of motion (ROM) appeared within 2 years of KHE onset. Associated chronic pain was reported in 12 patients. Bone-joint changes were common in patients with decreased ROM (75.9%). All the patients received at least one medical therapy including corticosteroids, vincristine, propranolol, and sirolimus. Sirolimus demonstrated the highest efficacy rate, with 94.7% of patients showing improvements in ROM and chronic pain.

CONCLUSION

Musculoskeletal complication can occur early in the disease course of KHE without KMP. Although no uniformly effective treatment modality was found, sirolimus demonstrated the best response in patients with KHE with decreased ROM and chronic pain.

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.

Kaposiform haemangioendothelioma: clinical features, complications and risk factors for Kasabach-Merritt phenomenon

BACKGROUND

Few studies have reported the clinical features, complications and predictors of Kasabach-Merritt phenomenon (KMP) associated with Kaposiform haemangioendothelioma (KHE).

OBJECTIVES

To determine the clinical characteristics present at diagnosis and to identify features that may aid clinicians in managing KHE.

METHODS

We conducted a cohort study of 146 patients diagnosed with KHE.

RESULTS

KHE precursors or lesions were present at birth in 52·1% of patients. In 91·8% of patients, lesions developed within the first year of life. The median age at diagnosis of KHE was 2·3 months (interquartile range 1·0-6·0). The extremities were the dominant location, representing 50·7% of all KHEs. Among KHEs in the cohort, 63·0% were mixed lesions (cutaneous lesions with deep infiltration). Approximately 70% of patients showed KMP. A KHE diagnosis was delayed by ≥ 1 month in 65·7% of patients with KMP. Patients with KMP were more likely to have major complications than patients without KMP (P = 0·023). Young age (< 6 months), trunk location, large lesion size (> 5·0 cm) and mixed lesion type were associated with KMP in a univariate analysis. In the multivariate analysis, only age [odds ratio (OR) 11·9, 95% confidence interval (CI) 4·07-34·8; P < 0·001], large lesion size (OR 5·08, 95% CI 2·24-11·5; P < 0·001) and mixed lesion type (OR 2·96, 95% CI 1·23-7·13; P = 0·016) were associated with KMP.

CONCLUSIONS

Most KHEs appeared before 12 months of age. KHEs are associated with various major complications, which can occur in combination and develop early in the disease process. Young age, large lesion size and mixed lesion type are important predictors of KMP.

Kaposiform hemangioendothelioma in children: a benign vascular tumor with multiple treatment options

BACKGROUND

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor affecting infants and young children. Although benign, it can be associated with an aggressive locally growing tumor and/or a life-threatening Kasabach-Merritt phenomenon (KMP). To date, only reviews of limited cases have been performed. We, therefore, conducted a comprehensive literature search to collect relevant data and make recommendations for future treatment trials.

METHODS

Review of the available literature between 1993 and 2017 revealed a total of 105 publications involving 215 patients of less than 21 years of age. To this, we added 12 from our department and 4 from the Cooperative Weichteilsarkomstudie database.

RESULTS

We found that KMP was present in 79% of the infants, in 47% of the 1-5-year olds, in 43% of the 6-12-year olds, and in 10% of the 13-21-year-old patients. KMP was present in nearly all (94%) patients with retroperitoneal tumors and in all patients with extra-regional tumors. The median size of a KHE without KMP was 12 cm² as compared to 49 cm² when associated with a KMP. With complete (not further classifiable if R0 or R1) resection, all patients were cured. If inoperable, response regarding KMP/regression of tumor size was seen in 29/28% with steroid-, 47/39% with vincristine-, 44/43% with interferon alpha-, 65/61% with anti-platelet agents-, and in 97/100% with sirolimus-containing therapies.

CONCLUSIONS

Patients with progressive KHE should undergo resection whenever it is considered a safe option. If inoperable, sirolimus should be the first choice for treating KMP and reducing tumor size.

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.

Management of Refractory Pediatric Kaposiform Hemangioendothelioma With Sirolimus and Aspirin

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor characterized by aggressive local invasion and a syndrome of platelet trapping known as Kasabach-Merritt phenomenon that, through deposition of platelet derived growth factors, may perpetuate the growth of the tumor. Although many cases of KHE are successfully treated with local control or low-intensity chemotherapy, some cases are often refractory even to aggressive treatment. Herein, we describe a patient with a refractory, recurrent KHE despite multiple attempts at local control and intensive chemotherapy, that ultimately was successfully treated with rationally designed and low-intensity combination therapy of sirolimus and aspirin.

Episode of Kasabach-Merritt phenomenon following Japanese encephalitis vaccination: Case report

Kasabach-Merritt phenomenon (KMP) is a rare potentially life-threatening consumptive coagulopathy characterized by thrombocytopenia and hypofibrinogenemia occurring associated with the vascular tumors kaposiform hemangioendothelioma (KHE) and tufted angioma (TA). A 10-month old male infant, diagnosed with KHE on his left leg, underwent a rapid increase of the lesion and severe thrombocytopenia, one day after the first dose of inactivated Japanese encephalitis (JE) vaccination. The episode of KMP was treated successfully by steroid. KMP is a rare complication of vaccination that physicians should be aware of. Giving up the following vaccination to provide the recurrence of KMP is not recommended.

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.

Integrin β3/Akt signaling contributes to platelet-induced hemangioendothelioma growth

Hemangioendothelioma (HE) is a type of angiomatous lesions that features endothelial cell proliferation. Understanding the mechanisms orchestrating HE angiogenesis can provide therapeutic insights. It has been shown that platelets can support normal and malignant endothelial cells during angiogenesis. Using the mouse endothelial-derived EOMA cell line as a model of HE, we explored the regulatory effect of platelets. We found that platelets stimulated EOMA proliferation but did not mitigate apoptosis. Furthermore, direct platelet-EOMA cell contact was required and the proliferation was mediated via integrin β3/Akt signaling in EOMA cells. SiRNA knockdown of integrin β3 and inhibition of Akt activity significantly abolished platelet-induced EOMA cell proliferation in vitro and tumor development in vivo. These results provide a new mechanism by which platelets support HE progression and suggest integrin β3 as a potential target to treat HE.

Multimodal treatment of Kasabach-Merritt syndrome arising from tufted angioma: A case report

Kasabach-Merritt syndrome (KMS) is a rare type of vascular tumor associated with a severely decreased platelet count. No standard guidelines for the treatment of the disease have been established so far. In the present study, a 1-year-old pediatric patient with KMS arising from tufted angioma was successfully and variously treated with steroids, vincristine, surgery and propranolol for 18 months. Systemic steroids stabilized the platelet count stable, while vincristine reduced the size of the tumor. Due to unpredictable response, the patient was operated. Combination of vincristine and propranolol was introduced post-surgery to improve the severely low platelet count of the patient. Following multimodal therapy for 18 months, there has been no evidence of recurrence or metastasis during 2 years of follow-up. Currently, the patient is alive and well. The management of KMS presents a challenge, and well-designed studies are required to clearly determine the benefits and risks of multidisciplinary treatment.

Sirolimus for Vincristine-Resistant Kasabach-Merritt Phenomenon: Report of Eight Patients

BACKGROUND

The use of sirolimus for patients with multidrug-resistant Kasabach-Merritt phenomenon (KMP) has been reported in recent years. We present the experience of a single center in treating vincristine-resistant KMP using sirolimus alone.

METHODS

Children with vincristine-resistant KMP who were treated with oral sirolimus alone were eligible for inclusion in the study. We evaluated responses according to graded response criteria and acute toxicities according to the National Cancer Institute Common Toxicity Criteria.

RESULTS

Between March 2012 and October 2014, eight patients underwent sirolimus treatment. The response rate of hematologic parameters was 100% (8/8). Three tumors shrank enough to allow excision. The tumors were resected after hematologic parameters normalized. Of the five patients with unresectable vascular lesions, three had complete response, and two had partial response of their tumors at the completion of long-term (39.7 ± 24.4 wks) sirolimus treatment. Grade 3 or 4 adverse events were not documented during treatment or follow-up. No recurrence or progression of the disease was observed during follow-up.

CONCLUSION

In this small case series, we found sirolimus to be highly effective, with minimal side effects, for vincristine-resistant KMP. A larger study to compare sirolimus and vincristine for KMP is warranted.

Hepatic angiosarcoma with clinical and histological features of Kasabach-Merritt syndrome

Hepatic angiosarcoma is a mesenchymal tumor originating from liver sinusoidal endothelial cells. It is an extremely rare malignant neoplasm accounting for less than 1% of primary malignant liver tumors. The deregulated coagulopathy that can be seen in hepatic angiosarcoma fulfills the clinical diagnostic criteria of disseminated intravascular coagulation. However, the mechanism that governs this coagulopathy has been poorly understood. This case report provides histological evidence of the consumption of coagulation factors along with trapped platelets occurring within the tumor, which is the foundation for the concept of Kasabach-Merritt syndrome (KMS). KMS is characterized by thrombocytopenia and hyperconsumption of coagulation factors within a vascular tumor. However, KMS associated with angiosarcoma has not been well recognized. This case report describes, for the first time, the histological evidence of KMS that occurred in an extremely rare mesenchymal malignant tumor of the liver.

Intracranial intraaxial cerebral tufted angioma: case report

Tufted angioma (TA) is a rare, slow-growing, vascular lesion that commonly presents as a solitary macule, papule, or nodule arising in the soft tissues of the torso, extremities, and head and neck in children and young adults. Adult-onset cases have been infrequently reported. While typically benign, TAs may be locally aggressive. Complete physical examination and hematological workup are recommended in patients with TA to exclude the presence of Kasabach-Merritt phenomenon (KMP). The authors describe the case of a 69-year-old man with a contrast-enhancing frontal lobe lesion, with surrounding vasogenic edema, which was treated by gross-total resection. Characteristic histological features of a TA were demonstrated, with multiple cannonball-like tufts of densely packed capillaries emanating from intraparenchymal vessels in cerebral cortex and adjacent white matter. Tumor recurrence was detected after 4 months and treated with adjuvant Gamma Knife radiosurgery. To the extent of the authors' knowledge, this case illustrates the first report of TA presenting in an adult as an intracranial intraaxial tumor without associated KMP. The fairly rapid regrowth of this tumor, requiring adjuvant treatment after resection, is consistent with a potential for locally aggressive growth in a TA occurring in the brain.

Surgical treatment of a huge kaposiform hemangioendothelioma in the chest wall: A case study

Kaposiform hemangioendothelioma, a rare vascular pediatric tumor often associated with Kasabach–Merritt phenomenon, is characterized by severe thrombocytopenia and consumptive coagulopathy. Kaposiform hemangioendothelioma is a severe disease and may progress quickly, resulting in a high mortality. However, standard treatment regimens for Kasabach–Merritt phenomenon have not yet been established. We reported here an infant with a large congenital kaposiform hemangioendothelioma in his chest wall who responded extremely well to surgical excision.

Anesthestic management of Kassabach-Meritt Phenomenon in an adult: case report

Background

Kasabach-Merritt phenomenon (KMP) is characterized by a vascular tumor with profound thrombocytopenia and consumptive coagulopathy that may presents significant challenges for anesthesiologist.

Case presentation

An 87-year-old man presented with kaposiform hemangioendothelioma involving the right leg in critical condition due to massive bleeding. Hematology investigations indicated the presence of KMP. Association of this type of tumor with KMP in adults has never been reported.

Conclusion

The present case report lays an emphasis on the potential difficulties during anesthetic management of this rare condition.

Interferon-alpha therapy for refractory kaposiform hemangioendothelioma: a single-center experience

Kaposiform hemangioendothelioma (KHE) is a relatively rare vascular tumor with an aggressive and infiltrating nature. Previous studies have revealed an exclusive relationship between KHE and Kasabach-Merritt Phenomenon (KMP), which is associated with high morbidity and mortality. No universally accepted treatment modality exists for refractory KHE with or without KMP. The aim of this study was to evaluate the safety and efficacy of interferon-alpha (IFN-α) therapy for treatment of refractory KHE. Twelve consecutive patients with KHE were treated with subcutaneous injections of IFN-α after other treatments had failed. Eleven patients exhibited a reduction in tumor size of more than 50%, and the platelet count for all five patients with KMP returned to normal level after IFN-α therapy. The duration of IFN-α treatment ranged from 3 months to 9 months (mean: 6.3 months). The response time for IFN-α treatment ranged from 10 days to 5 weeks (mean: 3.6 weeks). Additionally, no severe complications, such as neurological damage or spastic diplegia, were observed in these patients. In conclusion, our study suggested that IFN-α therapy is effective and safe for refractory KHE, and IFN-α may be used as an alternative after other treatments have failed.

GNA14 Somatic Mutation Causes Congenital and Sporadic Vascular Tumors by MAPK Activation

Vascular tumors are among the most common neoplasms in infants and children; 5%-10% of newborns present with or develop lesions within the first 3 months of life. Most are benign infantile hemangiomas that typically regress by 5 years of age; other vascular tumors include congenital tufted angiomas (TAs), kaposiform hemangioendotheliomas (KHEs), and childhood lobular capillary hemangiomas (LCHs). Some of these lesions can become locally invasive and unresponsive to pharmacologic intervention, leading to significant complications. Recent investigation has revealed that activating mutations in HRAS, KRAS, NRAS, GNAQ, and GNA11 can cause certain types of rare childhood vascular tumors, and we have now identified causal recurrent somatic activating mutations in GNA14 by whole-exome and targeted sequencing. We found somatic activating GNA14 c.614A>T (p.Gln205Leu) mutations in one KHE, one TA, and one LCH and a GNA11 c.547C>T (p.Arg183Cys) mutation in two LCH lesions. We examined mutation pathobiology via expression of mutant GNA14 or GNA11 in primary human endothelial cells and melanocytes. GNA14 and GNA11 mutations induced changes in cellular morphology and rendered cells growth-factor independent by upregulating the MAPK pathway. Our findings identify GNA14 mutations as a cause of childhood vascular tumors, offer insight into mechanisms of oncogenic transformation by mutations affecting Gaq family members, and identify potential targets for therapeutic intervention.

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.

Metastatic Angiosarcoma with Kasabach-Merritt Syndrome Responsive to Gemcitabine and Vinorelbine after Failure of Liposomal Doxorubicin and Paclitaxel: A Case Report

Kasabach-Merritt syndrome (KMS) describes a consumptive coagulopathy associated with certain vascular tumors. It is thought that platelets are destroyed as they circulate through the aberrant endothelial surfaces associated with these tumors. Most published literature describes infants with kaposiform hemangioendothelioma, but a similar syndrome can complicate angiosarcoma in adults. This report describes a man with metastatic angiosarcoma arising in the scalp in whom disease progression was complicated by profound thrombocytopenia consistent with KMS. His disease and associated KMS had progressed previously through paclitaxel and then through liposomal doxorubicin. It did not respond to paclitaxel and bevacizumab, but responded almost completely to chemotherapy with gemcitabine and vinorelbine. Six months later, progression through ongoing chemotherapy then responded to chemotherapy with cyclophosphamide and sirolimus.