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

ACG Clinical Guideline: Focal Liver Lesions

Focal liver lesions (FLLs) have become an increasingly common finding on abdominal imaging, especially asymptomatic and incidental liver lesions. Gastroenterologists and hepatologists often see these patients in consultation and make recommendations for management of multiple types of liver lesions, including hepatocellular adenoma, focal nodular hyperplasia, hemangioma, and hepatic cystic lesions including polycystic liver disease. Malignancy is important to consider in the differential diagnosis of FLLs, and healthcare providers must be familiar with the diagnosis and management of FLLs. This American College of Gastroenterology practice guideline uses the best evidence available to make diagnosis and management recommendations for the most common FLLs.

Congenital Vascular and Lymphatic Diseases

Over the past several centuries, the integration of contemporary medical techniques and innovative technologies, like genetic sequencing, have played a pivotal role in enhancing our comprehension of congenital vascular and lymphatic disorders. Nonetheless, the uncommon and complex characteristics of these disorders, especially considering their formation during the intrauterine stage, present significant obstacles in diagnosis and treatment. Here, we review the intricacies of these congenital abnormalities, offering an in-depth examination of key diagnostic approaches, genetic factors, and therapeutic methods.

[A Uncommon Case: Kasabach-Merritt syndrome with VACTERL Association]

The Kasabach-Merrit syndrome is characterized as the association of a vascular tumor, typically a caposiform hemangioendothelioma and rarely a tufted hemangioma, and a severe consumptive coagulopathy with potentially life-threatening thrombocytopenia. The severe coagulopathy with increased bleeding tendency must be considered before invasive procedures and often requires repeated platelet concentrate substitutions. We present a case of a mature male neonate with Kasabach-Merritt- Syndrome as well as VACTERL association. The VACTERL association describes a group of malformations. Our patient presented with anal atresia combined with tethered cord, and left renal agenesis. The VACTERL association as well as Kasabach-Merritt syndrome were found to be independent pathologies within this patient. A common occurrence or an association with each other has not been described in the literature so far. The challenging coagulation setting due to severe thrombocytopenia complicated the surgical management so far. Finally, mTOR-inhibitor sirolimus was successful in terms of tumor reduction and especially reduction of platelet consumption.

Sirolimus combined with glucocorticoids in the treatment of Kasabach-Merritt phenomenon in a neonate: A case report

RATIONALE

Kaposiform hemangioendothelioma is an aggressive vascular tumor that is often associated with life-threatening coagulopathies and Kasabach-Merritt phenomenon. Pathologic biopsies can provide a good basis for diagnosis and treatment. Therapy with srolimus combined with glucocorticoids may offer patients a favorable prognosis.

PATIENT CONCERNS

A large purplish-red mass on the knee of a child with extremely progressive thrombocytopenia and refractory coagulation abnormalities. Conventional doses of glucocorticoids alone failed to improve coagulation abnormalities and the child developed large cutaneous petechiae and scalp hematomas.

DIAGNOSIS

Kaposiform hemangioendothelioma combined with Kasabach-Merritt phenomenon.

INTERVENTIONS

The patient received prednisolone 2.0 mg/kg*d for 4 days. Blood products were transfused to ensure vital signs and to complete the pathologic biopsy. Sirolimus combined with prednisolone was given after clarifying the diagnosis of Kaposiform hemangioendothelioma.

OUTCOMES

The tumor basically disappeared on examination and the ultrasound showed a subcutaneous hyperechoic mass with normal blood flow.

LESSONS

Sirolimus combined with glucocorticoids is effective in controlling Kasabach-Merritt phenomenon and pathologic biopsy is important for definitive diagnosis.

Treatment practices and response in kaposiform hemangioendothelioma: A multicenter cohort study

BACKGROUND AND OBJECTIVES

Kaposiform hemangioendothelioma (KHE) and tufted angioma (TA) are rare vascular tumors in children historically associated with significant morbidity and mortality. This study was conducted to determine first-line therapy in the absence of available prospective clinical trials.

METHODS

Patients from 17 institutions diagnosed with KHE/TA between 2005 and 2020 with more than 6 months of follow-up were included. Response rates to sirolimus and vincristine were compared at 3 and 6 months. Durability of response and response to other treatment modalities were also evaluated.

RESULTS

Of 159 unique KHE/TA subjects, Kasabach-Merritt phenomenon (KMP) was present in 64 (40.3%), and only two patients were deceased (1.3%). Over 60% (n = 96) demonstrated treatment response at 3 months, and more than 70% (n = 114) by 6 months (no significant difference across groups). The vincristine group had higher radiologic response at 3 months compared to sirolimus (72.7% vs. 20%, p = .03), but there were no differences between these groups at 6 months. There were no differences in rates of recurrent or progressive disease between vincristine and sirolimus.

CONCLUSIONS

In this large, multicenter cohort of 159 patients with KHE/TA, rates of KMP were consistent with historical literature, but the mortality rate (1.3%) was much lower. Overall treatment response rates were high (>70%), and there was no significant difference in treatment response or durability of disease comparing sirolimus to vincristine. Our results support individualized treatment decision plans depending on clinical scenario and patient/physician preferences. Response criteria and response rates reported here will be useful for guiding future treatment protocols for vascular tumors.

Medical Management of Nonmalignant Vascular Tumors of the Head and Neck: Part 1

Vascular anomalies, broadly classified as nonmalignant tumors and malformations, consist of a multitude of disorders that have a wide range of symptoms and complications as well as overlapping clinical, radiologic, and histologic findings. Although usually difficult, distinguishing between nonmalignant vascular tumors and malformations, as well as the precise diagnosis within these distinctions, is critical because prognosis, therapy, and chronicity of care vary greatly. In contrast to normal endothelial turnover in vascular malformations, vascular tumors are characterized by the abnormal proliferation of endothelial cells and aberrant blood vessels.

Kaposiform hemangioendothelioma presented with raynaud phenomenon: a case report

BACKGROUND

Kaposiform hemangioendothelioma (KHE) is a rare vascular neoplasm affecting infants or young children. KHE includes a spectrum of lesions, ranging from small and superficial tumors to large and invasive lesions with Kasabach-Merritt phenomenon (KMP). Currently, no published studies have reported a KHE presenting as thrombocytopenia and Raynaud phenomenon.

CASE PRESENTATION

A 2-year-old boy with right hand swelling and thrombocytopenia was admitted to our hospital. His right hand turned swelling and red, even occasionally cyanotic. This condition became worse in response to cool environments and improved with warming, and platelet counts were between 50 ~ 80 × 10^9/L. Physical examination on admission revealed the swelling and frostbite-like rash of the right-hand fingers, and the skin temperature of the right hand was lower than the left. On day 3 of admission, chest CT results showed an irregular mass on the right side of the spine. The puncture biopsy demonstrated positive CD31, D2-40, and FLI1 immunohistochemical staining, but negative GLUT1 staining, confirming the diagnosis of KHE. Furthermore, endothelin-1 (ET1) expression levels significantly increased, and eNOS and A20 expression levels significantly decreased comparing with control patients. The patient received methylprednisolone and sirolimus treatments, and his condition gradually improved during the follow-up.

CONCLUSIONS

We reported the first case of KHE presenting with thrombocytopenia and Raynaud phenomenon. The development of Raynaud phenomenon could be associated with increased ET-1 and reduced eNOS and A20 expressions. Careful differential diagnosis of hidden KHE should be considered in children with thrombocytopenia and Raynaud phenomenon.

Platelet functional abnormalities in pediatric patients with kaposiform hemangioendothelioma/Kasabach-Merritt phenomenon

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor of infancy that is commonly associated with a life-threatening thrombocytopenic condition, Kasabach-Merritt phenomenon (KMP). Platelet CLEC-2, tumor podoplanin interaction is considered the key mechanism of platelet clearance in these patients. Here, we aimed to assess platelet functionality in such patients. Three groups of 6 to 9 children were enrolled: group A with KHE/KMP without hematologic response (HR) to therapy; group B with KHE/KMP with HR; and group C with healthy children. Platelet functionality was assessed by continuous and end point flow cytometry, low-angle light scattering analysis (LaSca), fluorescent microscopy of blood smears, and ex vivo thrombi formation. Platelet integrin activation in response to a combination of CRP (GPVI agonist) and TRAP-6 (PAR1 agonist), as well as calcium mobilization and integrin activation in response to CRP or rhodocytin (CLEC-2 agonist) alone, were significantly diminished in groups A and B. At the same time, platelet responses to ADP with or without TRAP-6 were unaltered. Thrombi formation from collagen in parallel plate flow chambers was also noticeably decreased in groups A and B. In silico analysis of these results predicted diminished amounts of CLEC-2 on the platelet surface of patients, which was further confirmed by immunofluorescence microscopy and flow cytometry. In addition, we also noted a decrease in GPVI levels on platelets from group A. In KHE/KMP, platelet responses induced by CLEC-2 or GPVI activation are impaired because of the diminished number of receptors on the platelet surface. This impairment correlates with the severity of the disease and resolves as the patient recovers.

Refractory kaposiform lymphangiomatosis relieved by splenectomy

Introduction

Kaposiform lymphangiomatosis (KLA) is a rare and complex lymphatic anomaly with a poor prognosis. There is no standard treatment, and drug therapies are the most common therapeutic method. However, some patients' symptoms become gradually aggravated despite medical treatment. Splenectomy may be an alternative option when pharmacological therapies are ineffective.

Materials and Methods

We reviewed and evaluated the cases of 3 patients with KLA who ultimately underwent splenectomy. Results: The lesions were diffusely distributed and involved the lungs and spleens of the 3 patients. Laboratory examinations revealed that all three patients had thrombocytopenia and reduced fibrinogen levels. All patients underwent symptomatic splenectomy after the medication failed. Surprisingly, their symptoms greatly improved. Histopathological investigation of the splenic lesions of the three patients confirmed the diagnosis of KLA. Immunohistochemical staining showed positivity for CD31, CD34, podoplanin, Prox-1 and angiopoietin 2 (Ang-2).

Discussion

This study aimed to review the features of KLA patients treated by splenectomy and explore the underlying link between splenectomy and prognosis. The reason for the improvement after splenectomy may be related to increased Ang-2 levels and platelet activation in patients with KLA. Future research should seek to develop more targeted drugs based on molecular findings, which may give new hope for the treatment of KLA.

Recurrent metastatic angiosarcoma presenting as Kasabach-Merritt syndrome

Angiosarcoma is an incredibly rare type of malignancy, accounting for only 1%-2% of all soft-tissue sarcomas globally. It is clinically, pathologically and radiologically difficult to diagnose angiosarcoma owing to its varied presentation with little or no well-defined imaging findings.Kasabach-Merritt syndrome is also a lesser-heard entity which carries extremely poor prognosis. It is primarily seen in infants with vascular malformations and in kaposiform haemangioendothelioma. It is a condition of consumptive coagulopathy and only few of the cases have been reported so far in the adults with a background of angiosarcoma.This report presents the case of a male in his 70s who was diagnosed with metastatic angiosarcoma and experienced a complicated disease course due to Kasabach-Merritt syndrome.

Impact of age and tumor size on the development of the Kasabach-Merritt phenomenon in patients with kaposiform hemangioendothelioma: a retrospective cohort study

Introduction

The Kasabach-Merritt phenomenon (KMP) is a severe complication of kaposiform hemangioendothelioma (KHE). The risk factors for KMP need further investigation.

Methods

The medical records of patients with KHE were reviewed. Univariate and multivariate logistic regression models were used for the risk factors for KMP, and the area under the receiver operator characteristic (ROC) curve was used to assess the predictive power of risk factors.

Results

A total of 338 patients with KHE were enrolled. The incidence of KMP was 45.9%. Age of onset (P < 0.001, odds ratio [OR] 0.939; 95% confidence interval [CI] 0.914-0.966), lesion size (P < 0.001, OR 1.944; 95% CI 1.646-2.296), mixed type (P = 0.030, OR 2.428; 95% CI 1.092-5.397), deep type (P = 0.010, OR 4.006; 95% CI 1.389-11.556), and mediastinal or retroperitoneal lesion location (P = 0.019, OR 11.864; 95% CI 1.497-94.003) were correlated with KMP occurrence through multivariate logistic regression. ROC curve analysis revealed that the optimal cutoffs were 4.75 months for the age of onset (P < 0.001, OR 7.206, 95% CI 4.073-12.749) and a lesion diameter of 5.35 cm (P < 0.001, OR 11.817, 95% CI 7.084-19.714). Bounded by a lesion size of 5.35 cm, we found significant differences in tumor morphology, age of onset, treatments, and hematological parameters. Using an onset age of 4.75 months as a cutoff, we found significant differences in tumor morphology, lesion size, hematological parameters, and prognosis.

Conclusion

For KHE patients with an onset age <4.75 months and/or lesion diameter >5.35 cm, clinicians should be wary of the occurrence of KMP. Active management is recommended to improve the prognosis.

Complex Lymphatic Anomalies: Report on a Patient Registry Using the Latest Diagnostic Guidelines

Objective: Generalized lymphatic anomaly (GLA), Gorham-Stout disease (GSD), kaposiform lymphangiomatosis (KLA), and central conducting lymphatic anomaly (CCLA) are rare, multisystem lymphatic disorders, referred to as complex lymphatic anomalies (CLAs). Their etiology remains poorly understood; however, somatic activating mutations have recently been discovered, and the results of targeted treatments are promising. This study aimed to elaborate on the phenotypic description of CLA. Methods: Thirty-six consecutive patients were recruited for the "GLA/GSD Registry" of the University Hospital of Freiburg, Germany (2015-2021). Clinical data were prospectively collected provided that a signed informed consent form was obtained. The latest proposed diagnostic guidelines were retrospectively applied. Results: Thirty-two patients (38% males) were included in the study; 15 GLA, 10 GSD, 3 KLA, and 4 CCLA patients were identified. Eighty-four percent already had symptoms by the age of 15 years. Osteolysis and periosseous soft-tissue infiltration were associated with GSD (p < 0.001 and p = 0.011, respectively), ascites and protein-losing enteropathy with CCLA (p = 0.007 and p = 0.004, respectively), and consumption coagulopathy with KLA (p = 0.006). No statistically significant differences were found in organ involvement, distribution of osteolytic lesions, number of affected bones and fractures. Twenty-five patients had complications; one patient with GLA died despite multimodal treatment. Spontaneous regression was seen in one patient with untreated KLA. Conclusions: CLA are rare, and their overlapping clinical presentations make differential diagnosis difficult. The characterization of our case series contributes to the phenotypic description and differentiation of these four clinical entities. A further understanding of their pathogenesis is crucial for evaluating targeted therapies and optimizing medical care.

Case Report: Pancreatic and hepatic kaposiform hemangioendothelioma presenting as consumptive coagulopathy and right hepatic atrophy

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor that causes progressive angiogenesis and lymphangiogenesis, which often occurs in the skin or soft tissue, with an acute onset and rapid progression. A 4-year-old girl was admitted to our hospital with a 2-year history of thrombocytopenia, combined with right hepatic atrophy and pancreatic lesion for 3 months. At the age of two, she developed purpura and thrombocytopenia was detected, after treatment with gamma globulin and corticosteroids, the platelet count normalized, but it dropped immediately at lower doses. One year after the cessation of corticosteroids therapy, the patient presented with abdominal pain and abnormal liver function and the magnetic resonance imaging (MRI) revealed right hepatic atrophy and pancreatic occupancy, but the first liver biopsy did not reveal any positive pathological results. By analyzing the clinical manifestations in conjunction with MRI and abnormal coagulation, we considered that the patient might be diagnosed as KHE with Kasabach-Merritt phenomenon, however, sirolimus treatment was ineffective and pancreatic biopsy only showed a tendency for tumors of vascular origin. Finally, we performed a Whipple operation after the right hepatic artery embolization, histological and immunohistochemical examination suggested KHE. Three months postoperatively, the patient's liver function, pancreatic enzymes and blood clotting function gradually returned to normal. KHEs may result in significant blood loss with worsening of the coagulopathy and functional impairment, timely surgical intervention for KHE is necessary when non-invasive or minimally invasive treatment is ineffective, or the symptoms of tumor compression are obvious.

Progressive kaposiform hemangioendothelioma and sirolimus-related severe thrombocytopenia

Kaposiform hemangioendothelioma is a locally invasive tumor and we were unable to find any previous reports of multifocal progression. Sirolimus, a mammalian target of rapamycin inhibitor, has been widely used to treat kaposiform hemangioendothelioma. Herein, we report a case of multifocal progressive kaposiform hemangioendothelioma, wherein sirolimus treatment caused severe thrombocytopenia. A 12-year-old East Asian girl presented with indurated dark-purple masses on her back. The patient had received three surgical interventions following the first appearance of the masses in 2012 and subsequent reappearances in 2014 and 2016. Kaposiform hemangioendothelioma was diagnosed based on radiological and pathological findings. Two more masses appeared in the following year. The patient was treated with oral sirolimus (2.5 mg/ m2/day) and developed grade 3 thrombocytopenia 8 days later. The patient was uneventfully relieved 5 days later after the withdrawal of sirolimus and the administration of appropriate medications. This rare case indicated that kaposiform hemangioendothelioma could be progressive with local metastatic characteristics in children. Besides, the severe sirolimus-induced complication highlights the importance of serum drug level monitoring during treatment. Physicians should be extremely cautious while treating kaposiform hemangioendothelioma patients with sirolimus.

Benign liver lesions 2022: Guideline for clinical practice of Associazione Italiana Studio del Fegato (AISF), Società Italiana di Radiologia Medica e Interventistica (SIRM), Società Italiana di Chirurgia (SIC), Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB), Associazione Italiana di Chirurgia Epatobilio-Pancreatica (AICEP), Società Italiana Trapianti d'Organo (SITO), Società Italiana di Anatomia Patologica e Citologia Diagnostica (SIAPEC-IAP) - Part II - Solid lesions

Benign liver lesions are increasingly diagnosed in daily clinical practice due to the growing use of imaging techniques for the study of the abdomen in patients who have non-specific symptoms and do not have an increased risk of hepatic malignancy. They include simple or parasitic hepatic cysts and solid benign tumors which differ widely in terms of prevalence, clinical relevance, symptoms and natural history and often lead to significant clinical problems relating to diagnosis and clinical management. Following the need to have updated guidelines on the management of benign focal liver lesions, the Scientific Societies mainly involved in their management have promoted the drafting of a new dedicated document. This document was drawn up according to the present Italian rules and methodologies necessary to produce clinical, diagnostic, and therapeutic guidelines based on evidence. Here we present the second part of the guideline, concerning the diagnosis and clinical management of hemangioma, focal nodular hyperplasia, and hepatocellular adenoma.

Advantages of laparoscopic hepatic hemangioma surgery in quality of life: a prospective study

BACKGROUND

Surgical intervention is the most accurate method for the treatment of hepatic hemangioma. The advantages of laparoscopic surgery on quality of life should be clarified by prospective studies.

METHODS

The sample sizes of the laparoscopic and open surgery groups were calculated based on previous retrospective literature. Intraoperative and postoperative parameters were prospectively collected and analyzed. Quality of life in both groups was predicted by a mixed linear model.

RESULTS

Sixty patients were enrolled in the laparoscopic surgery group and open surgery group. The laparoscopic group had a longer operation time (P = 0.040) and more hospitalization expenses (P = 0.001); however, the Clavien-Dindo classification and comprehensive complication index suggested a lower incidence of surgical complications in the laparoscopic group, with P values of 0.049 and 0.002, respectively. After mixed linear model prediction, between-group analysis indicated that the laparoscopic group had little impact on role-physical functioning and role-emotional functioning; in addition, within-group analysis showed a rapid recovery time on role-physical functioning and role-emotional functioning in the laparoscopic group. Quality of life in both groups recovered to the preoperative level within 1 year after the operation.

CONCLUSION

The advantages of laparoscopic hepatectomy for hepatic hemangioma were fewer postoperative complications, lower impact on quality of life and faster recovery from affected quality of life.

Combination therapy for pediatric patients with Kasabach-Merritt phenomenon: A single-center retrospective study

This study aimed to in the management of Kasabach-Merritt phenomenon (KMP), a severe thrombocytopenic coagulopathy that occurs in the presence of an enlarging vascular tumor. Here, we retrospectively evaluated 12 patients with KMP in Guangzhou Women and Children's Medical Center, Guangzhou Medical University, from 2017 to 2021. 12 patients, including 7 females and 5 males, were identified. Tumors were located in the leg (n = 4), neck (n = 1), face (n = 3), chest wall (n = 1), back (n = 2), and retroperitoneum (n = 1). A plaque-like lesion with ecchymosis was the most common cutaneous manifestation. All the patients underwent embolization therapy. Nine patients received steroid treatment and 7 patients were administered with sirolimus. The mean duration of treatment was 1.6 months. All the patients reported in this study were alive when discharged. Embolization combined with steroid and sirolimus appears effective in patients with KMP, as well as in those who experienced disease recurrence. However, a long-term follow-up of the children cured of KMP will be necessary to monitor its recurrence and improve the outcome.

Case report: A rare case of retroperitoneal kaposiform hemangioendothelioma with spinal involvement without abnormal platelet count in 18F-FDG PET/CT

Kaposiform hemangioendothelioma (KHE) is a rare vascular neoplasm that mostly appears in infancy or early childhood. Most KHE occurred on the limbs and trunk with cutaneous lesions. Approximately 12% of KHE patients manifested as deep masses and spinal involvement is extremely rare. KHE may develop into life-threatening thrombocytopenia and consumptive coagulopathy, known as the Kasabach-Merritt phenomenon (KMP), especially in patients with retroperitoneal involvement. The thrombocytopenia is usually severe, with a median platelet count of 21 × 10⁹/L at the initial presentation of KMP. Here, firstly we described a case of a 13-month-old girl with KHE who presented the movement limitation of the lower extremity caused by spinal involvement with a normal platelet count. ¹⁸F-fluorodeoxyglucose-positron emission tomography/CT (¹⁸F-FDG PET/CT) showed mildly elevated metabolism in the lesion, suggesting a probably low-grade malignant tumor. Then the patient was diagnosed with KHE by biopsy. After 6-month sirolimus monotherapy, the size of the retroperitoneal lesion was reduced significantly and the patient showed improvement in clinical symptoms. This case demonstrated the advantage of ¹⁸F-FDG PET/CT in the evaluation of disease activity in KHE and the possibility of using ¹⁸F-FDG PET/CT to guide therapy and prognostication.

Management of pancreatic kaposiform hemangioendothelioma with sirolimus in a pediatric patient: a case report and literature review

BACKGROUND

Kaposiform hemangioendothelioma (KHE) is a rare locally aggressive vascular tumor. The pancreas is not a common site of KHE, especially in pediatric patients. Given that no guidelines are available for the treatment of KHE, management is currently based on expert opinions and clinical experiences. Here, we report a case of pancreatic KHE with obstructive jaundice, which was treated successfully with oral sirolimus instead of radical surgery. Additionally, a literature review on pancreatic KHE was performed to summarize prior clinical experiences and the available treatments.

CASE DESCRIPTION

A 10-month-old Chinese male infant presented with obstructive jaundice without any signs of fever, abdominal pain, or distention. A detailed consultation revealed an uneventful history. The obstructive jaundice worsened significantly during 3 weeks of conservative therapy. A pancreatic mass was identified via radiological evidence, and a laparoscopic biopsy of the tumor was performed, which confirmed the diagnosis of pancreatic KHE based on histological findings. Oral sirolimus 0.8 mg/m² twice daily was administered at a steady serum concentration of 5-15 ng/mL, which led to a shrinkage in tumor size and resolution of jaundice. The patient showed no evidence of recurrence after 1 year of follow-up and is still on sirolimus treatment, which has been tolerated well up to the time of this report.

CONCLUSIONS

The pancreas is a rare location of KHE, which is a locally aggressive vascular tumor. Diagnosis is based on histological findings, and therapy should be multidisciplinary and individualized. Although sirolimus has been very successful in the treatment of KHE even without radical surgery, the possible risks of tumor recurrence and adverse effects warrant some caution.

How we approach coagulopathy with vascular anomalies

Some vascular anomalies can present with challenging hematologic aberrations. Kaposiform hemangioendothelioma (KHE) may be complicated with Kasabach-Merritt phenomenon (KMP) and stagnant blood flow in slow-flow malformations can promote activation and consumption of coagulation factors, which results in bleeding and clotting known as localized intravascular coagulopathy (LIC). These patients can experience significant morbidity secondary to pain due to thrombosis and are at higher risk of hematologic complications during surgical procedures. No standard of care has been established to prevent or manage these complications. This review focuses on the management of coagulopathy in children and adults with vascular anomalies.

Prevalence and Characteristics of Hepatic Hemangioma Associated with Coagulopathy and Its Predictive Risk Factors

Background: Knowledge of the relationships between hepatic hemangiomas and coagulopathy and the risk factors for hemangiomas is lacking. The aim of this study was to investigate the prevalence and characteristics of hepatic hemangiomas associated with coagulopathy, elucidate the causes of coagulopathy, and identify the predictive factors for hemangioma-related complications. Methods: In 281 consecutive patients with hepatic hemangiomas, we performed ultrasonography and conducted serum laboratory tests for liver function and six coagulation factors, i.e., platelets, as well as five coagulation fibrinolytic markers (prothrombin time (PT), fibrinogen, thrombin-antithrombin III complex (TAT), d-dimer, and fibrin and fibrinogen degradation products (FDP)) as indicators of coagulation disorder. Results: Among 281 patients, 56 (19.9%) had abnormal coagulation factors. Abnormal values of d-dimer were most frequently found among the six coagulation factors. The number of abnormal coagulation factors was significantly correlated with tumor size, M2BPGi, and HDL cholesterol, among which tumor size was the most significant independent predictor of the number of abnormal coagulation factors. Conclusions: The prevalence of hepatic hemangiomas associated with coagulopathy was relatively high and became more frequent with increases in tumor size. Predictive factors of hemangioma-related complications were found to be a tumor size of >5 cm in diameter and coagulopathy, especially the elevation of d-dimer.

Sirolimus plus prednisolone vs sirolimus monotherapy for kaposiform hemangioendothelioma: a randomized clinical trial

The Kasabach-Merritt phenomenon (KMP) in kaposiform hemangioendothelioma (KHE) is characterized by life-threatening thrombocytopenia and consumptive coagulopathy. This study compared the efficacy and safety of sirolimus plus prednisolone versus sirolimus monotherapy as treatment strategies for KHE with KMP in the largest cohort to date. Participants were randomized to receive either sirolimus in combination with a short course of prednisolone or sirolimus monotherapy for at least 12 months. The primary outcome was defined as achievement of a durable platelet response (platelet count >100×109/L) at week 4. Participants completed efficacy assessments 2 years after the initial treatment. At week 4, a durable platelet response was achieved by 35 of 37 patients given sirolimus and prednisolone compared with 24 of 36 patients given sirolimus monotherapy (difference 27.9%; 95% CI, 10.0% to 44.7%). Compared with the sirolimus monotherapy group, the combination treatment group showed improvements in terms of measures of durable platelet responses at all points during the initial 3-week treatment period, median platelet counts during weeks 1 to 4, increased numbers of patients achieving fibrinogen stabilization at week 4, and objective lesion responses at month 12. Patients receiving combination therapy had fewer blood transfusions and a lower total incidence of disease sequelae than patients receiving sirolimus alone. The frequencies of total adverse events and grade 3-4 adverse events during treatment were similar in both groups. The responses seen in patients with KHE with KMP were profound and encouraging, suggesting that sirolimus plus prednisolone should be considered a valid treatment for KHE with KMP. ClinicalTrial.gov, number NCT03188068.

Health-Related Quality of Life in Children With Kaposiform Hemangioendothelioma

BACKGROUND AND OBJECTIVE

Kaposiform hemangioendothelioma (KHE) is a rare, aggressive and borderline vascular tumor mainly occurring in infants and children. The aim of this study was to determine the health-related quality of life (HRQOL) in children with KHE.

MEASURES

A total of 91 children with KHE participated in this cross-sectional study. The HRQOL was assessed by the age-specific Pediatric Quality of Life Inventory Version 4.0 (PedsQL™ 4.0) Infant Scales, Family Information Form (FIF), Family Impact Module (FIM) and Generic Core Scales (GCS). For comparison, demographically matched healthy children were recruited as a control group. The main outcome measure of HRQOL was analyzed in the two groups. We determined related factors that influenced the HRQOL in children with KHE and their parents by using a stepwise multiple regression analysis.

RESULTS

The study found that the scores of each item in the family impact module (FIM) were lower than 75, which suggesting that KHE can make the parents of patients in a state of poor quality of life. The scores of physiological and psychosocial domains in all age groups of patients with KHE were lower than those of normal children (P < 0.01). Activity dysfunction is the factor influencing the physiological function score of all-age patients. KMP is the factor influencing the psychosocial function score of all-age patients.

CONCLUSIONS

The findings presented here suggest that patients with KHE have a poor HRQOL. KMP and activity dysfunction are risk factors for poor HRQOL in patients with KHE. However, lesion size, lesion location and education level of the mother and father were not related to the HRQOL.

Characterization of kaposiform lymphangiomatosis tissue-derived cells

BACKGROUND

Kaposiform lymphangiomatosis (KLA) is a recently characterized systemic lymphatic anomaly. Activation of RAS/MAPK and PI3K/AKT/mTOR pathways may affect KLA pathogenesis, but the cellular basis of KLA is unclear. Abnormal-spindle endothelial cells that express lymphatic endothelial cell (LEC) markers are characteristic of KLA histopathology. This study evaluated patient-derived KLA cells to establish their morphological and biological characteristics.

PROCEDURE

We established cell lines from primary KLA tissues of two patients with KLA and examined their morphological and functional characteristics, messenger RNA and protein expression profiles, gene mutations, and responses to inhibitors of the RAS/MAPK and PI3K/AKT/mTOR pathways.

RESULTS

Both KLA cell lines showed spindle-shaped morphology, stained positive for podoplanin (PDPN), and exhibited impaired tube-formation properties. They expressed LEC marker PDPN and mesenchymal stem cell markers (CD90, CD105) in the absence of endothelial cell markers (CD34, CD31, VWF), per real-time polymerase chain reaction. Both mTOR inhibitor rapamycin and MEK inhibitor trametinib inhibited growth of the two cell lines. A NRAS p.Q61R variant was found in one of two independent KLA tissue samples, but not in the KLA cells (per targeted next-generation sequencing); and KLA cells with this variant had elevated AKT phosphorylation levels. ERK phosphorylation levels were undetectable in both KLA cell lines.

CONCLUSIONS

Inhibition of the RAS/MAPK and PI3K/AKT/mTOR pathways may represent potential therapeutic targets in KLA. These patient-derived KLA cell lines will be useful research tools to elucidate KLA etiology, and could pave the way for basic, translational, and preclinical studies of this disease.

Liver transplantation for benign liver tumors

Benign liver tumors are common lesions that are usually asymptomatic and are often found incidentally due to recent advances in imaging techniques and their widespread use. Although most of these tumors can be managed conservatively or treated by surgical resection, liver transplantation (LT) is the only treatment option in selected patients. LT is usually indicated in patients that present with life-threatening complications, when the lesions are diffuse in the hepatic parenchyma or when malignant transformation cannot be ruled out. However, due to the significant postoperative morbidity of the procedure, scarcity of available donor liver grafts, and the benign course of the disease, the indications for LT are still not standardized. Hepatic adenoma and adenomatosis, hepatic hemangioma, and hepatic epithelioid hemangioendothelioma are among the most common benign liver tumors treated by LT. This article reviews the role of LT in patients with benign liver tumors. The indications for LT and long-term outcomes of LT are presented.

[Clinical features of Kasabach-Merritt syndrome: an analysis of 16 neonates]

OBJECTIVE

To study the clinical features, treatment, and prognosis of neonates with Kasabach-Merritt syndrome (KMS), and to provide a reference for optimizing the diagnosis and treatment of this disease.

METHODS

A retrospective analysis was performed for the clinical and follow-up data of 16 neonates with KMS who were admitted to the Anhui Children's Hospital, Anhui Medical University, from January 2016 to December 2020.

RESULTS

Of the 16 neonates, there were 13 boys (81%) and 3 girls (19%), with an age of 1 hour to 10 days on admission. Among these neonates, 13 (81%) had cutaneous hemangioma (2 in the head and face, 5 in the trunk, and 6 in the extremities) and 3 (19%) had liver hemangioma. The main clinical manifestations of bleeding tendency and scattered petechiae and ecchymosis were observed in 10 neonates (62%). All the 16 neonates had varying degrees of thrombocytopenia and coagulation disorders. They all received glucocorticoid treatment after admission and 7 (44%) of them had response, among whom 4 experienced recurrence. Among the neonates with no response to glucocorticoid treatment, 3 received sirolimus treatment, among whom 1 had the tumor volume reduced by 58.8% after 4 weeks of treatment, with platelet count and coagulation function returning to normal, while 2 had no significant reduction in tumor volume or significant increase in platelet count and achieved a tumor volume reduced by (43.7±0.4)% after 4 weeks of combined treatment with bleomycin arterial embolization, with platelet count and coagulation function returning to normal. After 4 weeks of bleomycin arterial embolization alone for 4 neonates, tumor volume was reduced by (52.0±3.4)%, and platelet count and coagulation function returned to normal. Blunt and sharp dissection was performed for 2 neonates. The tumor was removed completely during surgery in the 2 neonates, with no infection or recurrence after surgery, and platelet count and coagulation function returned to normal. The postoperative pathological examination showed Kaposiform hemangioendothelioma in 1 out of the 2 neonates.

CONCLUSIONS

KMS has characteristic clinical manifestations, histopathological features, and laboratory examination results. The KMS neonates who are not sensitive to glucocorticoids can achieve a good curative effect through arterial embolization and sirolimus treatment.

Intracranial kaposiform hemangioendothelioma presenting as epistaxis: a rare case report with review of literature

INTRODUCTION

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor of intermediate malignancy with tendency for local invasion and recurrence. The tumor almost exclusively occurs in children, especially in infants. Intracranial KHE are extremely rare with only two cases reported in the literature.

REPORT

We report the clinical and pathological features of this rare tumor arising from basitemporal region in a 21-month child. Our case did not present with Kasabach-Merritt phenomenon. Histopathological examination confirmed the diagnosis of KHE.

CONCLUSION

KHE should be considered in the differential diagnosis of intracranial extra-axial neoplasm in children, and histopathological examination plays an important role in distinguishing KHE from its morphologic mimics. It is essential to diagnose KHE due to its locally aggressive nature.

Management of Refractory Mandibular Kaposiform Hemangioendothelioma with Sirolimus: A Case Report and Review of the Literature

Kaposiform hemangioendothelioma (KHE) is a rare vascular neoplasm of intermediate malignancy that generally occurs in infancy and early childhood. Typically, the lesion arises from superficial or deep soft tissues of the extremities, trunk and retroperitoneum. The paucity of reported cases of head and neck KHEs is evidence of the rarity of the disease in this region. We report on the presentation and treatment of KHE in an 11-month-old boy who presented with a mandibular lesion. We include a brief discussion about the differential diagnosis of KHE. Management involved preoperative interventional radiology, surgical excision and chemotherapeutic treatment with Sirolimus. The lesion resolved without evidence of relapse 12 months later.

Sirolimus for the treatment of kaposiform hemangioendothelioma: In a trough level-dependent way

With the accumulation of clinical practice, sirolimus is now widely viewed as an effective agent in kaposiform hemangioendothelioma (KHE) treatment using a dose based on experience. Therefore, this retrospective research aimed to provide evidence-based suggestions on the most appropriate dose and trough level of sirolimus. All unresectable KHE cases diagnosed at our center from January 2016 to December 2019 were included. Sirolimus monotherapy was initiated when there was no sign of Kasabach-Merritt phenomenon (KMP) at a dose of 0.8 mg/m² twice a day in order to keep the trough level at 5-20 ng/mL. Patients' clinical information, tumor volume change, trough level fluctuation, and complication occurrence were all recorded. Efficacy represented by tumor shrinkage speed and safety manifested by complication grades were compared between different trough level groups (5-10 vs. 10-15 vs. >15 ng/mL). Twenty-one patients (10 girls and 11 boys) were enrolled. There were eight patients in the 5-10 ng/mL group, seven in the 10-15 ng/mL group, and six in the more than 15 ng/mL group. Trough level over 10 ng/mL manifested better efficacy in tumor shrinkage (t-test, p = 0.011) while a level over 15 ng/mL had no further benefit in efficacy (t-test, p = 0.65). In addition, tumors at a central location reacted better to sirolimus (t-test, p = 0.022). No significant differences were observed in complication occurrence among different concentrations, although boys seemed to be at higher risk of more severe complications (>grade II, χ² -test, p = 0.009, odds ratio = 4.52, range = 1.20-17.24). It proved to be most efficacious in the management of KHE at a trough level between 10 and 15 ng/mL. Such concentration was safe and well tolerated.

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.

Association of tumor size and internal echo pattern with coagulopathy associated with hepatic hemangioma

Little is known concerning causal factors associated with the size and echogenicity of hepatic hemangiomas. The aim of the present study was to investigate the associations between tumor size and echo pattern and coagulation factors, and to elucidate the growth pattern of hemangiomas. In 214 consecutive patients with hepatic hemangiomas, ultrasonography was performed to determine total tumor number, size, echogenicity and location, and serum laboratory tests for liver function and coagulation factors were carried out. The ultrasonographic appearance of hemangiomas was homogeneous in 75.7% of cases and mixed in 24.3% of cases. A mixed echo pattern was seen in 1 out of 145 masses (0.7%) with a diameter <20 mm, in 30 out of 48 (62.5%) with a diameter of 20-40 mm, and in all of the 21 (100%) with a diameter >40 mm. Platelet counts (P<0.0001) and fibrinogen levels (P<0.01) were lower in patients with larger and mixed tumors. Levels of thrombin-antithrombin III complex (TAT), D-dimer, and fibrin and fibrinogen degradation products (FDP) were significantly elevated along with an increase in tumor size (all P<0.0001), and the number of patients with the abnormal values of TAT, D-dimer, and FDP was significantly higher in the mixed group than in the homogeneous group (all P<0.0001). Fibrinogen (P<0.01), platelet count (P<0.001), portal vein diameter (P<0.0001), splenic index (P<0.01), and levels of TAT, D-dimer and FDP (all P<0.0001) were significantly associated with tumor size. Multivariate analysis revealed TAT, D-dimer and FDP as independent predictors of tumor size. The internal echo pattern became mixed as size increased. The size and echogenicity of hemangiomas were closely associated with coagulation factors. Therefore, it was speculated that differences in size and echogenicity were caused by intratumoral thrombosis and subsequent hemorrhage.

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.

Transarterial Embolization in Neonatal Kasabach-Merritt Syndrome

Background: Kasabach-Merritt syndrome (KMS) is characterized by large hemangiomas and persistent thrombocytopenia, which may result in visceral hemorrhage and disseminated intravascular coagulation. This study aimed to evaluate the value of transarterial embolization (TAE) in neonatal KMS patients. Patients and Methods: The clinical course of 11 neonates with KMS who underwent TAE in the Department of Neonatology, Anhui Provincal Children's Hospital, Anhui Medical University, China, were reviewed retrospectively. Results: Eleven neonates with KMS (nine male and two female) were admitted to our hospital between the age of 1 h and 6 days. All were born with progressively enlarged hemangiomas and persistent thrombocytopenia. The largest lesion had its maximum size reached at 15 × 8 × 8 cm. Eight patients had cutaneous hemangiomas (1 right face, one oropharynx, one left upper arm, two back, one left lumbar, one right lower leg, and one right thigh), and three patients had liver hemangiomas. All 11 patients underwent TAE. Nine patients underwent two TAEs, and two patients underwent only one embolization procedure. They all obtained >80% devascularization of their lesions without a major complication. The platelet count increased at 2-5 days after treatment and reached normal count and coagulation profile at 18-28 days after the TAE. Conclusions: TAE is a safe and effective alternative therapy for neonatal KMS patients.

Additive value of transarterial embolization to systemic sirolimus treatment in kaposiform hemangioendothelioma

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor in children, which can be accompanied by life-threatening thrombocytopenia, referred to as Kasabach-Merritt phenomenon (KMP). The mTOR inhibitor sirolimus is emerging as targeted therapy in KHE. As the sirolimus effect on KHE occurs only after several weeks, we aimed to evaluate whether additional transarterial embolization is of benefit for children with KHE and KMP. Seventeen patients with KHE and KMP acquired from 11 hospitals in Germany were retrospectively divided into two cohorts. Children being treated with adjunct transarterial embolization and systemic sirolimus, and those being treated with sirolimus without additional embolization. Bleeding grade as defined by WHO was determined for all patients. Response of the primary tumor at 6 and 12 months assessed by magnetic resonance imaging (MRI), time to response of KMP defined as thrombocyte increase >150 × 10³ /μL, as well as rebound rates of both after cessation of sirolimus were compared. N = 8 patients had undergone additive embolization to systemic sirolimus therapy, sirolimus in this group was started after a mean of 6.5 ± 3 days following embolization. N = 9 patients were identified who had received sirolimus without additional embolization. Adjunct embolization induced a more rapid resolution of KMP within a median of 7 days vs 3 months; however, tumor response as well as rebound rates were similar between both groups. Additive embolization may be of value for a more rapid rescue of consumptive coagulopathy in children with KHE and KMP compared to systemic sirolimus only.

Successful treatment of a patient with Kasabach-Merritt syndrome and multiple giant hepatic hemangiomas

Kasabach–Merritt syndrome (KMS) is a rare complication of hemangioma. KMS mostly occurs in the pediatric population with typical clinical manifestations, including thrombocytopenia, consumptive coagulation, and purpura. However, the pathogenesis of KMS is still unclear and the KMS therapy is controversial. We report here a case of KMS and multiple, giant, hepatic hemangiomas in a 34-year-old female patient who was successfully treated in our hospital. Glucocorticoid along with supportive treatments was administrated immediately to reverse fatal disseminated intravascular coagulation and acute hemolysis. After the acute phase, glucocorticoid was tapered slowly and sirolimus was added to treat the hemangiomas. In conclusion, the risk factors of gestation, interventional treatment, and autoimmune disturbance might contribute to the pathogenesis of KMS. Additionally, treatment with glucocorticoid and sirolimus is effective in KMS and multiple giant hepatic hemangiomas.

Chronic lymphedema in patients with kaposiform hemangioendothelioma: incidence, clinical features, risk factors and management

Objectives

There are no cohort studies of chronic lymphedema in patients with kaposiform hemangioendothelioma (KHE). We sought to characterize the incidence, clinical features, risk factors and management of chronic lymphedema in patients with KHE.

Methods

We conducted a multicenter retrospective analysis of patients who had a minimum of 3 years of follow-up after the onset of KHE and/or Kasabach–Merritt phenomenon (KMP). Clinical features were reviewed to determine the possible cause of chronic lymphedema. The degree of lymphedema, risk factors and management strategies were analyzed.

Results

Among the 118 patients, chronic lymphedema was confirmed by lymphoscintigraphy 1 year after the onset of KHE and/or KMP in 13 patients. In 8 patients with lymphedema, extremity swelling was evident in the presence of KHE and/or KMP. In all patients with lymphedema, a unilateral extremity was affected, along with ipsilateral KHE. Most (84.6%) patients reported moderate lymphedema. Lymphedema was more common in patients with larger (≥ 10 cm) and mixed lesions involving the extremities (P < 0.01). A history of KMP and sirolimus treatment were not predictors of lymphedema (P > 0.05). Overall, 76.9% of patients received sirolimus treatment after referral, including 53.8% who presented extremity swelling before referral. Seven (53.8%) patients received compression therapy. Five (38.5%) patients reported lymphedema-associated decreased range of motion at the last follow-up.

Conclusions

Chronic lymphedema is a common sequela of KHE and can occur independently of KMP and sirolimus treatment. Patients with large and mixed KHE involving extremities should be closely monitored for this disabling complication.

Coagulation issues in vascular anomalies

Vascular anomalies, comprised of vascular tumors and malformations, are frequently associated with coagulopathy. Recognition of and familiarity with these vascular anomaly-associated hematologic abnormalities prior to surgery or interventional procedures is essential for pre-operative pre-operative planning. Complicated coagulopathies present within the framework of either Kasabach-Merritt phenomenon (KMP) or localized intravascular coagulopathy (LIC), and their management benefits from the expertise of a hematologist for optimal intra- and peri‑operative care. Furthermore, with the recent broadening of understanding of vascular anomalies and the addition of new classification sub-groups, distinctions of these two classic coagulopathy phenotypes have been recognized. This review summarizes the main features of these coagulopathies, described according to their vascular anomaly type, highlighting clinical aspects relevant to surgical management.

Successful management of a pregnant woman with Kasabach-Merritt syndrome and preeclampsia: A case report

INTRODUCTION

Kasabach-Merritt Syndrome (KMS) is an extremely rare disease in adults, which lead to consumptive coagulopathy characterized by severe hypofibrinogenemia and thrombocytopenia. PATIENT CONCERNS:: a 25-year-old Chinese pregnant women complicated by preeclampsia and KMS presented with refractory postpartum hemorrhage and incision bleeding after cesarean section.

DIAGNOSIS

The diagnosis of KMS was made based on clinical manifestation of Kaposiform Hemangioendothelioma, severe hypofibrinogenemia and thrombocytopenia.

INTERVENTIONS

After a poor response to massive blood products transfusion for 1 week, corticosteroid treatment was initiated for 3 days.

OUTCOMES

The patient reached a normal platelet count and a mild anemia within 4 weeks. Two months later, all laboratory values had returned to normal, and the incision was healing well.

CONCLUSION

Pregnancy complicated by preeclampsia and surgery may have contributions for the development of Kasabach-Merritt syndrome. Corticosteroid is indicated in the episode of acute Kasabach-Merritt syndrome after the failure of massive blood transfusion.

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

•

Thrombocytopenia in cancer patients is correlated with poor prognosis.

•

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

•

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

•

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

•

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.