Kasabach-merritt phenomenon: a retrospective study of treatment with vincristine

Treatment experience for different risk groups of Kaposiform hemangioendothelioma

Background

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor with a high risk of mortality. Few studies with large samples of KHE have been reported. KHE may develop into the Kasabach-Merritt phenomenon (KMP), which is characterized by thrombocytopenia and consumptive coagulopathy. The features of severe symptomatic anemia and life-threatening low platelets make the management of KHE associated with KMP challenging.

Objective

The aim of this study was to examine the clinical characteristics of patients with KHE and discuss the treatment experience for different risk groups of KHE.

Methods

Through a retrospective review of 70 patients diagnosed with KHE between 2017 and 2022 in our center, we classify lesions into three clinicopathological stages based on the tumor involving depth, and divided the severity of KHE into three levels by estimating clinicopathological stages and severity of thrombocytopenia. Treatments of different severity groups were estimated with sufficient data.

Results

In our cohort, 27% were neonates, and KHE lesion occurred at birth in 84% of patients. There was a slight male predominance (32 girls and 38 boys). Common clinical characteristics included associated coagulation disorder (100%), locally aggressive cutaneous blue-purple mass (89%), thrombocytopenia (78%), and local pain or joint dysfunction (20%). The lower extremities were the dominant location (35%), followed by the trunk (29%), the maxillofacial region and neck (24%), and the upper extremities (10%). Of the total cohort, 78% developed KMP; the median age at which thrombocytopenia occurred was 27.8 days. The median platelet count of patients who were associated with KMP was 24,000/µL in our cohort. Ninety-two percent of patients were given surgery treatment and 89% of these patients were given high-dose methylprednisolone (5-6 mg/kg daily) before surgery. In 55 patients with KMP, 36% were sensitive to high-dose corticosteroid therapy. Patients from the low-risk group (eight cases) underwent operation, all of whom recovered without recurrence after a maximum follow-up of 5 years. Out of 26 patients from the high-risk group, 25 underwent surgery treatment, with 1 case undergoing secondary surgery after recurrence and 1 case taking sirolimus. Out of 36 cases from the extremely high-risk group, 32 underwent surgery (including 2 cases who underwent external carotid artery ligation and catheterization), 3 of whom underwent secondary operation after recurrence, and the remaining 4 cases took medicine. The mean length of having sirolimus was 21 months; two cases stopped taking sirolimus due to severe pneumonia. Two cases died at 1 and 3 months after discharge.

Conclusions

Our study describes the largest assessment of high-risk patients with KHE who have undergone an operation to date, with 5 years of follow-up to track recovery, which provides invaluable knowledge for the future treatment of patients with KHE and KMP from different risk groups: Early surgical intervention may be the most definitive treatment option for most patients with KHE; multimodality treatment is the best choice for the extremely high-risk group.

The use of mTOR inhibitors for the treatment of kaposiform hemangioendothelioma. A systematic review

BACKGROUND

Kaposiform hemangioendothelioma (KHE) is a locally aggressive and potentially lethal vascular tumor of infancy. Current consensus recommendations include the use of vincristine and/or systemic steroids as first-line treatment. Mammalian target of rapamycin (mTOR) inhibitors represent a promising therapy for patients with KHE. The goal of our study is to critically assess the existing literature on outcomes of patients with KHE treated with mTOR inhibitors.

METHODS

We conducted a literature search from 1 January 2000, to 30 April 2022. Articles reporting outcomes of patients treated with mTOR inhibitors for KHE were included. Descriptive statistics were used to describe and summarize the outcomes of the treatment.

RESULTS

We included 327 patients with a mean age at diagnosis of 9.1 months (SD ± 9). Patients were treated with an mTOR inhibitor for a mean of 15.2 months (SD ± 4.1). A total of 315 (96.3%) patients had positive outcomes including improvement of the tumor size, symptoms and/or laboratory parameters in 227 (85%) and complete remission in 38 (12%). Seven (2%) patients did not respond to treatment and seven (2%) died of sepsis (4), Kasabach-Merritt phenomenon complications (1), cardiac and liver failure due to ductus arteriosus (1), or metastatic disease (1).

CONCLUSION

This systematic review supports the efficacy and safety of mTOR inhibitors for KHE. Their use resulted in positive outcomes in terms of decreased symptoms, reduction in tumor size and improvement in biochemical parameters with a mortality rate of 2%. According to these findings, we suggest revised consensus treatment guidelines for KHE with mTOR inhibitors potentially considered first-line therapy.

How we approach the diagnosis of a vascular anomaly

Vascular anomalies represent a diverse group of complex disorders that can cause significant complications, including coagulopathies, pain, and decreased function. The diagnosis of vascular anomalies is often challenging due to heterogeneity of presenting phenotypes and overlapping clinical features with other pediatric conditions. Pediatric hematologists/oncologists (PHO) are uniquely positioned for an essential role in diagnosing, managing, and coordinating the multidisciplinary care required to maximize the quality of life of these patients. Here, we review the diagnostic approach involved in patients with vascular anomalies and utilize cases to highlight the challenges involved, and how PHOs can play a vital part in the care of these patients.

Lower Gastrointestinal Bleeding Because of Kasabach-Merritt Syndrome Showing an Impressive Response to Sirolimus

Kasabach-Merritt syndrome is a rare but life-threatening disease in which a rapidly growing vascular tumor induces localized intravascular coagulation, causing thrombocytopenia, microangiopathic hemolytic anemia, and consumption coagulopathy. It presents mainly in infants and young children. We present an adult with recurrent and severe lower gastrointestinal bleeding due to Kasabach-Merritt syndrome, treated successfully with sirolimus after multiple other failed interventions.

Comprehensive Therapy for Infant Vascular Tumor Associated With Kasabach-Merritt Phenomenon-Single-Center Primary Experience

OBJECTIVE

To introduce our single-center experience of infant vascular tumor associated with Kasabach-Merritt phenomenon (KMP) which received combined medicine treatment with intralesional laser photocoagulation (ILP) and sclerotherapy.

METHODS

A retrospective study was conducted using medical records of all children with a diagnosis of kaposiform hemangioendothelioma (KHE) or tufted angioma (TA) associated with KMP treated with medicine, intralesional laser photocoagulation (ILP), and sclerotherapy between February 2017 and November 2020. Clinical features, response to comprehensive therapy, and outcomes were recorded.

RESULTS

A total of 23 patients including nine females (39%) and 14 males (61%) were identified. The mean age was 6.9 months (age range, 11 days-2 years) at the time of treatment. Nine children (39%) demonstrated sensitivity to single corticosteroid therapy; 14 children (61%) received combined therapy with intravenous Vincristine (VCR) and corticosteroid therapy. All children had at least two ILP and sclerotherapy performed, with a mean of 3.5 procedures (range: 2-6). Of these 14 children, only one experienced a relapse of thrombocytopenia and the remaining 13 children had no clinical symptoms recurred.

CONCLUSION

The combined therapy modalities could induce a more rapid tumor response and resolution of KMP and decrease the rebound rates. This research presents a novel and safe multi-modality treatment for infant vascular tumors associated with KMP.

Standards of care for Kasabach-Merritt phenomenon in China

Kasabach-Merritt phenomenon (KMP) is a rare disease that is characterized by severe thrombocytopenia and consumptive coagulation dysfunction caused by kaposiform hemangioendothelioma or tufted hemangioma. This condition primarily occurs in infants and young children, usually with acute onset and rapid progression. This review article introduced standardized recommendations for the pathogenesis, clinical manifestation, diagnostic methods and treatment process of KMP in China, which can be used as a reference for clinical practice.

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.

A case report of Kaposiform haemangioendothelioma; response with propranolol and steroids

Background

Kaposiform haemangioendothelioma is a rare vascular tumor and may involve skin, deep soft tissue or bone. It is a locally aggressive tumor usually seen in infants. Here we report a case of kaposiform hemagioendothelioma in a child who responded to propranolol and steroids.

Case presentation

A 3-year-old male child presented with a swelling below his right knee with characteristic violet skin lesion. There was no evidence of Kasabach–Merritt phenomenon. After no improvement with several attempts at debridement and anti-tubercular treatment; a diagnosis of Kaposiform Haemangioendothelioma was reached on the basis of overall clinical picture and histology. The child was treated with propranolol and steroids and had an excellent clinical response and a near complete resolution on imaging at 5 months.

Conclusions

These cases are often misdiagnosed and despite a delay in diagnosis have good outcomes with appropriate multimodality management. This case highlights the unique and typical characteristics of kaposiform haemangioendothelioma.

Endothelial cell malignancies in infants, children and adolescents: Treatment results of three Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Endothelial cell malignancies are extremely rare in childhood. New identification of genetic abnormalities (WWTR1:CAMTA1 translocation) helps to recognize potential therapeutic targets. Little is known about treatment and outcome of these patients.

METHODS

Clinical course, treatment, and outcome in patients with endothelial cell malignancies treated within the Cooperative Weichteilsarkom Studiengruppe (CWS) trials CWS-91, -96, -2002P, and the Soft-Tissue Sarcoma Registry (SoTiSaR) were analyzed (1991-2019).

RESULTS

Patients had angiosarcoma (AS) (n = 12), malignant epithelioid hemangioendothelioma (EHE) (n = 16), and kaposiform hemangioendothelioma (KHE) (n = 13). The median age was 5.39 years (range, 0.8-17.34); 33 patients had localized disease (LD), and 8 patients had metastatic disease. Therapy consisted of chemotherapy (CHT) (AS n = 8, EHE n = 9, KHE n = 5), interferon or new agent therapy (EHE n = 5, 2 KHE n = 2), microscopically or macroscopically complete resection (AS n = 3, EHE n = 6, KHE n = 3), and radiotherapy (AS n = 6, EHE n = 2, KHE n = 1). Two patients (KHE) had watch-and-wait strategy resulting in stable disease. Complete remission (CR) was achieved in AS (10/12; 83%), EHE (10/16; 63%), and KHE (5/13; 38%). The five-year EFS and OS for patients with AS was 64% (± 29 CI 95%) and 80% (± 25, CI 95%), with EHE 62% (± 24, CI 95%) and 78% (± 23, CI 95%), with KHE 33% (± 34, CI 95%) and 92% (± 15, CI 95%), respectively. Complete resection was a significant prognostic factor for AS, LD for EHE.

CONCLUSIONS

Endothelial cell malignancies in childhood have a fair outcome with multimodal treatment. New treatment options are needed for metastic disease.

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.

Bifocal Tibial Kaposiform Hemangioendothelioma Responsive to Vincristine Therapy: A Case Report

BACKGROUND Kaposiform hemangioendothelioma is a rare locally aggressive vascular endothelial-derived spindle cells neoplasm. Herein, we report a rare case of bifocal tibial kaposiform hemangioendothelioma. CASE REPORT A 9-year-old female presented with a 2-year history of pain and swelling in the left leg. The patient had a high plasma level of the D-dimer and fibrinogen. Radiography revealed a centric lytic lesion on the left proximal tibial metaphysis and an eccentric lateral distal tibial metaphyseal. Histopathologic examination of the sample taken from the distal tibia revealed a dense spindle cell tumor with lobular architecture composed of compact spindle cells compressing small slit-like vascular spaces, forming glomeruloid nests. No necrosis was identified. Based on these findings and the positive immunohistochemical staining for CD31, CD34, and D2-40, the patient was diagnosed with kaposiform hemangioendothelioma. Treatment was started by using vincristine chemotherapy, after which the patient developed temporary peroneal neuropathy, which improved over the next 3 months. CONCLUSIONS Bifocal tibial kaposiform hemangioendothelioma lesions are unique in pediatric patients and can be successfully treated with vincristine chemotherapy. In these cases, the treating physician should be aware of peroneal neuropathy as a potential complication of vincristine administration.

Vincristine and sirolimus in the treatment of kaposiform haemangioendothelioma

AIM

Kaposiform haemangioendothelioma (KHE) is a rare, potentially life-threatening vascular tumour that is often associated with thrombocytopenia and coagulopathy, known as the Kasabach-Merritt phenomenon (KMP). Because of the rarity and complexity of KHE, the optimal paradigm for treating KHE has yet to be elucidated. We aim to assess the efficacy and safety of vincristine and sirolimus for the treatment of KHE.

METHODS

A comprehensive review of the literature was conducted from January 1993 to June 2018. A total of 15 studies were selected for the meta-analysis. Five studies included 75 individuals and reported the response and side effects to vincristine in the treatment of KHE with or without KMP. A total of 10 studies that included 127 individuals reported the response and safety of sirolimus for treating KHE with or without KMP.

RESULTS

The pooled odds ratio (OR) for the effectiveness of vincristine was 0.72. The pooled OR for the effectiveness of sirolimus was 0.91. The side effects associated with vincristine during the treatment included neuropathy, abdominal pain, loss of appetite and mild elevations of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The side effects associated with sirolimus therapy included bronchitis; lymphopenia; elevated AST, ALT and platelets; hyperlipidaemia; opportunistic infection; mild reversible leukopenia; mucositis; fever; pain and skin rash/vomiting and diarrhoea.

CONCLUSIONS

This systematic review showed a high efficacy of vincristine and sirolimus in the treatment of KHE. Based on the available data in the literature, it appears that sirolimus is potentially an efficacious and safe treatment option for KHE. Further randomised, controlled trials are recommended.

Current treatment and management of infantile hemangiomas

Infantile hemangiomas, otherwise known as infantile capillary hemangiomas, strawberry hemangiomas, or strawberry nevi, are nonmalignant vascular tumors that commonly affect children. The natural disease course typically involves growth for up to a year, followed by regression without treatment over a period of years with no cosmetic or functional sequelae. Less commonly, however, infantile hemangiomas can become a threat to vision or even life depending on location and size of the lesion. In addition, infantile hemangiomas, particularly those involving the face, may be disfiguring and result in lifelong sequelae. β-blockers have become a mainstay of therapy given their relatively low-risk profile and efficacy. Other treatment modalities previously described in the literature include corticosteroids (both intralesional and systemic), imiquimod, vincristine, bleomycin A5, and interferon α. More recently, angiotensin-converting enzyme inhibitors such as captopril have been used. Laser therapy and, less commonly, surgical excision are also available treatment options. We review current recommended management and treatment of capillary hemangiomas and discuss the benefits and risks of all previously reported treatment modalities.

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 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 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.

A Case Report of 2 Sirolimus-Related Deaths Among Infants With Kaposiform Hemangioendotheliomas

Kaposiform hemangioendothelioma (KHE) is a rare infiltrative vascular tumor that is potentially life-threatening when presenting with Kasabach-Merritt phenomenon (KMP). KMP is clinically characterized as severe thrombocytopenia and hypofibrinogenemia and therefore is associated with a high mortality rate. There is no standard of cure for KHE currently. Potential medications, including corticosteroids, propranolol, and chemotherapy drugs such as sirolimus, are often used for alleviating KHE symptoms. Although some case reports of sirolimus treatment have shown promising results with recovered coagulant parameters, the off-target effects may cause severe problems. Here we describe 2 cases of infant patients with KHE and KMP who were scheduled to receive sirolimus on a long-term basis. However, both patients developed paroxysmal cough and tachypnea shortly after the onset of sirolimus treatment and succumbed to infection thereafter. This report reveals a potential risk of infection in sirolimus-treated infant patients. The fatal complication highlights the importance of antibiotic prophylaxis and serum sirolimus level monitoring to ensure the safe use of sirolimus in the treatment of infant patients with KHE.

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.

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 the treatment of progressive kaposiform hemangioendothelioma: A multicenter retrospective study

Kaposiform hemangioendothelioma (KHE) is an aggressive disease with high morbidity and mortality. The aim of this study was to retrospectively evaluate the efficacy and safety of sirolimus for the treatment of progressive KHE. A multicenter, retrospective cohort study was conducted in patients with progressive KHE treated with sirolimus. A total of 52 patients were analyzed. Thirty-seven (71%) patients exhibited Kasabach-Merritt phenomenon (KMP) and were significantly younger than the patients without KMP [95% confidence interval (CI), 14.39-41.61; p < 0.001]. Patients without KMP were all treated with sirolimus alone, whereas 21 KMP patients with severe symptoms received short-term combination therapy with prednisolone. Overall, 96% and 98% of patients showed improved relief of notable symptoms and/or improved complications at 6 and 12 months after treatment, respectively. After sirolimus treatment, significant decreases in mean severity scores occurred at 6 months (95% CI, 2.23-2.54, p < 0.001) and 12 months (95% CI, 1.53-1.90, p < 0.001). Compared to KMP patients, patients without KMP showed a response that was similar to but less pronounced during the 12 months of treatment (95% CI, 40.87-53.80; p < 0.001). For subgroup analysis of KMP patients, there were no significant differences in tumor shrinkage between those treated with combination therapy and those receiving sirolimus alone (95% CI, 18.11-25.02; p > 0.05). No patients permanently discontinued treatment due to toxicity-related events, and no drug-related deaths occurred. Sirolimus was effective and safe for the treatment of progressive KHE. Sirolimus may be considered as a first-line therapy or as part of a multidisciplinary approach for the treatment of KHE.

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.

Kaposiform haemangioendothelioma: a review with emphasis on histological differential diagnosis

Kaposiform haemangioendothelioma (KHE) is a rare, locally aggressive/borderline vascular tumour primarily seen in neonates and children. KHE is occasionally associated with Kasabach-Merritt phenomenon and tends to have a poor clinical prognosis. While the histological features of tufted angiomas and KHE overlap, some believe tufted angiomas are a milder, benign, more localised counterpart of KHE. The other histological differential diagnoses of KHE include infantile haemangioma, congenital haemangioma, spindle cell haemangioma, verrucous malformation/haemangioma, and Kaposi sarcoma. Microscopically, KHE is characterised by confluent nodules of neoplastic spindled endothelial cells involving multiple planes of tissue which are positive for endothelial, lymphatic, and smooth muscle markers. Resection, once thought to be the definitive treatment for KHE, is often unattainable due to the extent of the lesion; thus, single or combination chemotherapies have been used to treat these patients. Sirolimus has recently been reported to be a successful agent to treat refractory and complicated cases of KHE.

Kasabach-Merritt Phenomenon: Classic Presentation and Management Options

Kasabach-Merritt phenomenon (KMP) is a rare consumptive coagulopathy associated with specific vascular tumors, kaposiform hemangioendothelioma, and tufted angioma. Kasabach-Merritt phenomenon, characterized by profound thrombocytopenia, hypofibrinogenemia, elevated fibrin split products, and rapid tumor growth, can be life-threatening. Severe symptomatic anemia may also be present. With prompt diagnosis and management, KMP can resolve and vascular tumors have been shown to regress. This review highlights the clinical presentation, histopathology, management, and treatment of KMP associated with kaposiform hemangioendothelioma, and less frequently tufted angioma. A classic clinical case is described to illustrate the presentation and our management of a patient with KMP.

A Rare Presentation of Isolated Congenital Splenic Hemangioma With Kasabach-Merritt Syndrome

INTRODUCTION

Splenic hemangiomas (SHs) are the most common benign neoplasms of the spleen. However, they are rare in the newborn period. We present an extremely rare case of congenital SH complicated by Kasabach-Merritt syndrome.

CASE PRESENTATION

A 2.93 kg male infant was delivered at term with a prenatal diagnosis of a left infrarenal mass diagnosed by ultrasound at 35 weeks of gestation. Magnetic resonance imaging demonstrated a well-defined splenic mass with multiple flow voids and scattered areas of high intensity suggestive of hemorrhage. He developed anemia, thrombocytopenia, and coagulopathy which required transfusion with packed red cells, platelets, cryoprecipitate, and fresh frozen plasma. Excision biopsy of the spleen led to resolution of anemia, thrombocytopenia, and coagulopathy. The diagnosis of SH was confirmed by histopathology. At 2 months outpatient follow-up, the patient was growing well without any evidence of tumor recurrence.

CONCLUSIONS

Congenital SH is a rare entity that can be fatal if the potential complication of Kasabach-Merritt syndrome is not anticipated, evaluated, and promptly treated. Our patient had a favorable outcome with early surgical excision of the SH.

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.

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.

[Management of vascular anomalies in children]

Vascular anomalies, which are broadly identified as "angiomas", are rare entities and often unknown by the medical sphere. They are divided in two different categories which carry different prognosis and management: "vascular tumors" and "vascular malformations". Their precise identification is crucial and involves a good knowledge of the biological classification published by Mulliken and Glowacki and that has recently been updated by the International Society for the Study of Vascular Anomalies (ISSVA). Vascular tumors are benign, common, inborn or not and most of the time disappear with growth. Vascular malformations are always congenital and growth with the child. They can involve type of vessels solely or combined with others. A rheologic differentiation between slow and fast flow malformations is essential in order to characterize the seriousness of the lesion. Frequently, their diagnosis is clinically established and the anamnesis is conducted to answer three questions that are the time of revelation of the lesion ("When?"), its aspect ("What?") and its evolution ("How?"). Further investigations are usually not required but a non-invasive imaging technique such as Doppler ultrasound could be useful if a doubt exists. Surgery is not mandatory and must always be well thought because its consequences might be disastrous. It must be left to cosmetic sequelae of these lesions or to lesions that are totally resectable without causing any unacceptable deformation.

Response to Paclitaxel in an Adult Patient with Advanced Kaposiform Hemangioendothelioma

BACKGROUND

Kaposiform hemangioendothelioma (KHE) is a rare neoplasm of vascular origin that typically arises from the skin or soft tissues as a solitary tumor. The optimal therapy for this disease is still unknown. We report the case of an adult patient presenting with metastatic KHE of the spleen, who had a partial response after treatment with paclitaxel.

CASE PRESENTATION

A 36-year-old man presented in November 2012 with a nontraumatic rupture of the spleen. A splenectomy was performed, and the pathology was consistent with a nonspecific vascular proliferation. Follow-up scans revealed lytic bone lesions and liver metastasis. A biopsy of the liver was performed and confirmed KHE. The decision was made to proceed with treatment with gemcitabine and docetaxel, which was discontinued due to myelotoxicity. The patient was then transferred to our institution, and a pathology review supported the diagnosis of metastatic KHE. His disease remained stable until February 2014, when he developed progression in the liver. Chemotherapy was restarted with paclitaxel, and a partial response was documented after 3 cycles. Unfortunately, disease progression occurred after 24 weeks, and subsequent treatments included prednisone, doxorubicin, interferon-α, gemcitabine, and ifosfamide, without any response. The patient developed Kasabach-Merritt phenomenon and passed away 1 week later due to a major gastrointestinal bleeding.

CONCLUSIONS

This case report suggests that paclitaxel could be considered as a treatment option for advanced KHE, a rare condition for which no standard treatment exists.

Imaging features of kaposiform lymphangiomatosis

BACKGROUND

Kaposiform lymphangiomatosis is a rare, aggressive lymphatic disorder. The imaging and presenting features of kaposiform lymphangiomatosis can overlap with those of central conducting lymphatic anomaly and generalized lymphatic anomaly.

OBJECTIVE

To analyze the imaging findings of kaposiform lymphangiomatosis disorder and highlight features most suggestive of this diagnosis.

MATERIALS AND METHODS

We retrospectively identified and characterized 20 children and young adults with histopathological diagnosis of kaposiform lymphangiomatosis and radiologic imaging referred to the vascular anomalies center between 1995 and 2015.

RESULTS

The median age at onset was 6.5 years (range 3 months to 27 years). The most common presenting features were respiratory compromise (dyspnea, cough, chest pain; 55.5%), swelling/mass (25%), bleeding (15%) and fracture (5%). The thoracic cavity was involved in all patients; all patients had mediastinal involvement followed by lung parenchymal disease (90%) and pleural (85%) and pericardial (50%) effusions. The most common extra-thoracic sites of disease were the retroperitoneum (80%), bone (60%), abdominal viscera (55%) and muscles (45%). There was characteristic enhancing and infiltrative soft-tissue thickening in the mediastinum and retroperitoneum extending along the lymphatic distribution.

CONCLUSION

Kaposiform lymphangiomatosis has overlapping imaging features with central conducting lymphatic anomaly and generalized lymphatic anomaly. Presence of mediastinal or retroperitoneal enhancing and infiltrative soft-tissue disease along the lymphatic distribution, hemorrhagic effusions and moderate thrombocytopenia (50-100,000/μl) should favor diagnosis of kaposiform lymphangiomatosis.

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.

Vascular Anomalies in Pediatrics

A standardized classification system allows improvements in diagnostic accuracy. Multidisciplinary vascular anomaly centers combine medical, surgical, radiologic, and pathologic expertise. This collaborative approach tailors treatment and management of vascular anomalies for affected individuals.

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.

[Is alfa-interferon still current in the management of Kasabach-Merritt syndrome?]

Kasabach-Merritt syndrome (KMS), characterized by thrombocytopenia, may complicate vascular tumors such as kaposiform hemangioendothelioma and tufted angioma. We report on two infants, respectively 2 months and 15 days old at the onset of symptoms, the first of whom presented with a left cervico-occipito-scapular hemangioma with parotid extension, and the second with a vascular tumor located on the left shoulder with fast extension on the left inferior hemithorax and the left arm. Thrombocytopenia (< 20 G/L) was associated in both cases. Treatment comprised first high-dose corticosteroids (2mg/kg) in association with vincristine (1mg/m(2)/week). Interferon was introduced as third-line treatment at 3 MIU/m(2)/day. In the first patient, interferon was effective both on thrombocytopenia and tumor in 2 months. In the second patient, the first interferon treatment was not effective despite 6 months of therapy. However, a second treatment 8 years later was successful. After 10 and 3 years follow-up, respectively, there were no side effects and most particularly no neurologic complications. These two observations open the discussion of the role of interferon (3 MIU/m(2)/day) as well as new therapies in the control of angiogenesis in case of failure of first-line treatment of complicated KMS vascular tumors.

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.

The importance of early diagnosis and treatment of kaposiform hemangioendothelioma complicated by Kasabach-Merritt phenomenon

Kaposiform hemangioendothelioma (KHE) is a locally aggressive vascular tumor that may be complicated by Kasabach-Merritt phenomenon (KMP), a profound thrombocytopenia resulting from platelet trapping within a vascular tumor, either KHE or tufted angioma (TA). Typical features also include low fibrinogen and elevated D-dimers. It is well known that KMP is not caused by infantile hemangiomas. Management of vascular tumors complicated by KMP is challenging, and it is common for referral centers to receive patients in critical medical condition after multimodality treatment failure of vascular anomalies. Our aim is to communicate the importance of early diagnosis and treatment of KHE associated with KMP. A full-term male newborn with KHE complicated by KMP is reported. Treatment with vincristine, aspirin and ticlopidine normalized the coagulation parameters within one week, requiring a total of six doses of vincristine, seven months of ticlopidine and 17 months of aspirin. Early diagnosis and treatment of KHE complicated by KMP may allow the administration of fewer doses of vincristine and avoid the use of corticosteroids.

Other vascular tumors

Vascular tumors are rare in children and adults. Classification of these tumors has been difficult, especially in the pediatric population, due to the rarity of these lesions, the unusual morphologic appearance, their diverse clinical behavior, and no independent stratification for pediatric tumors. In 2013, The World Health Organization updated the classification of soft tissue vascular tumors. Pediatric tumors were not independently stratified and the terminology was mostly left unchanged, but the intermediate category of tumors was divided into locally aggressive and rarely metastasizing. These tumors are treated with multimodality therapy and therefore need the guidance of an interdisciplinary team for best care.