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

Consensus statement for the diagnosis, treatment, and prognosis of kaposiform hemangioendothelioma

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor that typically presents in infancy or early childhood. As awareness of KHE increases, it is imperative that the management of KHE be updated to reflect the latest evidence-based guidelines. The aim of this study was to integrate the literature and Chinese expert opinions to provide updated recommendations that will guide the diagnosis, treatment, and prognosis of patients with KHE. According to this consensus statement, 28 nationally peer-recognized experts in vascular anomalies and an expert in evidence-based medicine were assembled and formed three consensus subgroups. A series of key themes and questions were developed for each group, including recommendations for diagnosis, treatment, and prognosis. A systematic search was conducted for English-language articles published in PubMed and other relevant studies identified by the expert panel. A diagnosis of KHE necessitates the integration of clinical, imaging, and histologic features. The treatment of KHE should be tailored to the specific characteristics of each patient, including the size of the lesion, the presence of symptoms, the location, and the overall condition of the patient. In addition to focusing on the disease itself, it is also important to consider the complications of KHE and their impact on prognosis. The recommendations presented herein are intended to assist in the guidance of clinical practice and decision-making in patients with KHE, with the objective of improving patient outcomes.

Kaposiform hemangioendothelioma in the mandibular gingiva: a rare case report with literature review

Kaposiform hemangioendothelioma (KHE) is a locally aggressive vascular tumor in neonates and children. KHE can occur anywhere in the body, but occurrence in the oral cavity is exceptionally rare. The clinical features of KHE are similar to those of oral lesions, such as infantine hemangioma, pyogenic granuloma, and chronic periodontitis. However, unlike other oral lesions, KHE invades neighboring tissue planes and recurs frequently as malignancy. Moreover, some instances of KHE are accompanied by a life-threatening condition named Kasabach-Merritt phenomenon. Correct diagnosis of KHE is very difficult despite its importance. KHE lacks not only specific clinical characteristics, but also distinct imaging findings even with advanced modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). Thus, KHE is often misdiagnosed as another disease. We report a case of KHE in the mandibular gingiva. The enlarged gingival mass showed reddish granulomatous appearance with intact mucosal surface. It was misdiagnosed as another disease and underwent simple resection, but it recurred several times. In radiological examination using periapical radiography, cone beam computed tomography, and magnetic resonance imaging, no specific findings other than ill-defined alveolar bone destruction were observed. The subsequent pathological examination showed CD-31 and CD-34 positive, and D2-40 and HHV-8 negative. This report includes discussion about radiological, clinical, and histopathological features of the lesion and comprehensive literature review.

Similarities and differences in the clinical features and management of primary lymphedema and kaposiform hemangioendothelioma associated with lymphedema in children

Background

Primary lymphedema (PLE) and kaposiform hemangioendothelioma-related lymphedema (KLE) are rare vascular anomalies (VAs). This study aimed to examine the clinical features, management, and prognosis of PLE and KLE.

Method

The clinical features, imaging, treatments, and outcomes of 12 patients with PLE and 12 patients with KLE were retrospectively reviewed.

Results

The mean age at which signs/symptoms were diagnosed was 68.2 months for PLE patients and 25 months for KLE patients. In PLE, the involvement of multiple sites is common, whereas in KLE, it typically affects a single site. Morbid obesity, which is common in adult patients, is rare in pediatric PLE and KLE patients. Imaging agent accumulation was observed in KLE but not in PLE via lymphoscintigraphy. In contrast, complications of PLE primarily involve skin and soft tissue, whereas musculoskeletal system complications are more common in KLE. Regarding prognosis, most patients stabilize or even experience lesion regression after standard treatment.

Conclusion

PLE and KLE share clinical symptoms. PLE often involves multiple sites, whereas KLE typically presents unilaterally with local lymphatic stasis. Standardized treatment enables the majority of children with lymphedema to control the disease without progression, with KLE showing potential reversibility. Given their rarity, a multidisciplinary approach is crucial for diagnosis and management.

[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.

Case Report: Recurrent blepharal kaposiform hemangioendothelioma in an adult patient

Background

Kaposiform hemangioendothelioma (KHE) is a rare and invasive vascular tumor that mainly occurs in children and is rarely seen in adults. We report a case of KHE found on the eyelid of an adult patient.

Case report

We present an adult patient in whom KHE recurred 6 months after tumor resection. He underwent second surgical resection and intraoperative chemotherapy. There was no evidence of recurrence at the 3-year follow-up.

Conclusion

KHE in adults is easy to be misdiagnosed. KHE can be treated by surgical resection. Complete resection of the tumor and intraoperative chemotherapy may help prevent a recurrence.

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.

Kaposiform hemangioendothelioma of skull base with dura invasion in a pediatric patient: a case report

Kaposiform hemangioendothelioma is an extremely rare vascular tumor which shows aggressive local growth. We present a case of rapid growing vascular skull tumor with dura invasion in a pediatric patient with neurofibromatosis type 1. A 14-year-old male complained of headache and dizziness for 1 month after minor head trauma. Brain magnetic resonance imaging (MRI) revealed a 5-cm-sized tumor in the left frontotemporal bone with internal hemorrhage and cystic changes. The gross total resection of tumor was done. At the 7-month follow-up, brain MRI revealed a recurrent skull tumor with intracranial dura mass. He underwent second surgery, and the pathologic diagnosis was suggestive of Kaposiform hemangioendothelioma. For this vascular proliferative tumor, mTOR inhibitor was treated for 6 months, and there was the recurred nodular-enhancing mass along the sphenoid ridge. After additional 2 months of medication, the following MRI revealed a decreased nodular-enhancing mass.

Toxic effects of sirolimus and everolimus on the development and behavior of zebrafish embryos

Sirolimus and everolimus have been widely used in children. These mammalian target of rapamycin (mTOR) inhibitors have shown excellent efficacy not only in organ transplant patients as immunosuppressive agents but also in patients with some other diseases. However, whether mTOR inhibitors can affect the growth and development of children is of great concern. In this study, using zebrafish models, we discovered that sirolimus and everolimus could slow the development of zebrafish, affecting indicators such as survival, hatching, deformities, body length, and movement. In addition to these basic indicators, sirolimus and everolimus had certain slowing effects on the growth and development of the nervous system, blood vessels, and the immune system. These effects were dose dependent. When the drug concentration reached or exceeded 0.5 μM, the impacts of sirolimus and everolimus were very significant. More interestingly, the impact was transient. Over time, the various manifestations of experimental embryos gradually approached those of control embryos. We also compared the effects of sirolimus and everolimus on zebrafish, and we revealed that there was no significant difference between these drugs in terms of their effects. In summary, the dose of sirolimus and everolimus in children should be strictly controlled, and the drug concentration should be monitored over time. Otherwise, drug overdosing may have a certain impact on the growth and development of children.

Kaposiform hemangioendothelioma complicated by Kasabach-Merritt phenomenon in an infant girl

Key Clinical Message

We report a successful treatment course of an infant with mediastinal Kaposiform hemangioendothelioma. As the current complex of diseases is rare and calls for highly specialized treatment, large prospective studies are lacking. This case provides an example of balanced treatment complicated by Kasabach-Merritt phenomenon, life-threatening infections, and pericardial effusion.

Abstract

Kaposiform hemangioendothelioma (KHE) and tufted angioma are vascular benign tumors that can be associated with the rare condition Kasabach-Merritt Phenomenon (KMP). KMP is characterized by consumption coagulopathy with severe thrombocytopenia, hypofibrinogenemia, and elevated D-dimer. We here report successful treatment of a female infant with a mediastinal KHE where treatment was complicated by KMP, life-threatening infections, and pericardial effusion. Due to the absence of randomized clinical trials, there is currently no standardized treatment protocol available for KHE. In our case, the infant was treated successfully with prednisolone, vincristine, and sirolimus.

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.

Clinical and imaging features of Kaposiform hemangioendothelioma in infants

Objective

Kaposiform hemangioendothelioma (KHE) is a locally aggressive tumor of vascular origin. This study investigated the clinical and imaging features of KHE to provide a reference for its early diagnosis.

Methods

The clinical and imaging findings of 27 clinically confirmed KHE cases (including 21 with focal lesions and 6 with diffuse lesions) between January 2016 and December 2021 were retrospectively analyzed.

Results

The mean age of the 27 patients was 105 ± 80.27 days. Twenty-two (81.5%) of these patients had Kasabach-Merritt phenomenon. Most KHEs were located in the trunk and/or extremities (22/27). Ultrasonography showed heterogeneous echogenicity and/or striated hypoechoic bands with abundant or patchy blood flow within the tumor. On plain computed tomography (CT), they appeared as heterogeneous lesions isodense with the muscles, with a CT value of 29.58 ± 11.53 HU. In the arterial phase, the KHEs showed striated or lamellar heterogeneous enhancement, with a CT value of 153.91 ± 52.11 HU after enhancement. All KHEs showed uneven and high signal intensity on T2-weighted imaging, mixed high and low signal intensity on fat-saturated images, and no significant diffusion restriction on diffusion-weighted imaging.

Conclusion

KHEs can occur in various locations and present as highly infiltrative and heterogeneous masses that can invade the skin, adjacent muscles, and bones. A vascularized mass with purpuric skin changes, with uneven and high T2WI signal is highly suggestive of the diagnosis of KHE.

Kaposiform haemangioendothelioma of the spine associated with fixed hyperlordotic deformity and Kasabach-Merritt Syndrome: a case report and literature review

Kaposiform haemangioendothelioma (KHE) is a rare childhood disease classified by the International Society for the Study of Vascular Anomalies (ISSVA) as a locally aggressive vascular tumor. It has been reported to affect any site, with a predilection for the extremities and trunk. Although it typically manifests as an enlarging cutaneous or soft tissue lesion, less than 10% of cases have no skin involvement, with the retroperitoneum being the most frequently involved extracutaneous site. Approximately twenty cases of KHE with bony involvement have been reported in the literature to date, with only five of those cases involving the spine specifically.We present a, rare case of KHE who presented with progressive fixed hyperlordotic deformity, multiple non-specific spinal lesions, and abnormal blood tests, posing a clinical and radiological diagnostic challenge. Additionally, we conducted a thorough review of the literature to compare and contrast the various multimodality imaging manifestations of KHE involving the spine.

Retroperitoneal kaposiform hemangioendothelioma with kasabach-merritt phenomenon in children: A case report and review of the literature

Objective

To investigate the clinical features, diagnosis and treatment methods and prognosis of retroperitoneal Kaposiform hemangioendothelioma (R-KHE) in children.

Methods

The clinical data of an infant with R-KHE was retrospectively analyzed. Literature on R-KHE in pediatrics were retrieved in databases including Wanfang, CNKI and PubMed as of April 2022.

Results

A 1 month and 6 days female infant with R-KHE was reported. After the diagnosis was confirmed by biopsy and pathological examination, the patient was treated by interventional embolization, and a combined therapy with glucocorticoid, vincristine, sirolimus and propranolol. The patient has been followed up for 1 year and 2 months, and is still alive with tumor. Through literature search, a total of 15 children, together with the case in our report, were included. The main manifestations were diversity among those patients. 14 cases have combined Kasabach-Merritt phenomenon (KMP). 6 cases accepted surgery plus drug therapy. 4 cases accepted only surgery, and 4 cases only accepted drug therapy. While drug therapy plus radiotherapy were employed to 1 case. Improvement was observed in 11 cases, with significantly reduced tumor and survival with tumor. Tumor disappeared completely in 2 cases. While 2 cases suffered death.

Conclusion

R-KHE has diverse clinical presentations and non-specificity in symptoms and imaging examinations, and most cases accompanied with KMP. Methods for R-KHE treatment include surgical resection, interventional embolization and drug therapy. Close attention needs to be paid to the adverse reactions of the drug during the course of treatment.

Severe consumptive hypothyroidism in hepatic hemangioendothelioma

OBJECTIVES

Consumptive hypothyroidism may occur in hepatic hemangioendothelioma. The altered expression of deiodinases inactivates peripheral thyroid hormones. As a result, serum levels of free triiodothyronine and free thyroxine are reduced to varying degrees. There are no established recommendations for the dosage of sirolimus for this particular indication. We describe for the first time the course of treatment with low-dose sirolimus.

CASE PRESENTATION

We present a 5-week-old infant with hepatic hemangioendothelioma and severe consumptive hypothyroidism. Due to hepatic infiltration he showed signs of right heart strain. Therapy of hemangioendothelioma was initiated with propranolol and, in the absence of response, methylprednisolone was added. Treatment was continued with low-dose sirolimus (due to side effects) and propranolol. Hypothyroidism was managed with levothyroxine and liothyronine.

CONCLUSIONS

Consumptive hypothyroidism due to cutaneous hemangioma and hepatic hemangioendothelioma can be managed with propranolol and low-dose sirolimus. Treatment of severe hypothyroidism may require a combinational therapy by substitution of both T3 and T4.

Cocktail therapy with prednisolone, vincristine and sirolimus for Kasabach‑Merritt phenomenon in 10 infants

Kasabach-Merritt phenomenon (KMP) is a life-threatening condition caused by rare vascular tumors. To reduce drug resistance observed in monotherapy of KMP with prednisone, vincristine (VCR) or sirolimus, the present study evaluated the efficacy and safety of triad therapy in the treatment of KMP. A total of 10 KMP infants managed with prednisolone, VCR and sirolimus in The Second Affiliated Hospital of Xi'an Jiaotong University (Xi'an, China) between April 2017 and August 2021 were retrospectively reviewed. The three female and seven male infants with KMP underwent cocktail therapy with prednisone, VCR and sirolimus. At diagnosis, the infants, aged 49.1±41.0 days, showed laboratory test results with platelet counts 22±15.4x10⁹/l, fibrinogen 81.7±26.9 mg/dl and D-dimer 38649±13443.6 ng/ml. The average maximal diameter of the tumors at diagnosis was 84.5±25.1 mm. KMP risk is increased by large tumors with deep lesions infiltrating the muscle. Platelet counts normalized after a median 10 days (range, 5-69 days) of treatment. With combination therapy maintained for 46.8±24.4 days, ultrasound showed that the thickness of the tumors decreased by 51% from 28.9±12.1 to 13.9±6.2 mm. Neutropenia and gastrointestinal disorders were the most common adverse effects. The present study found that the cocktail therapy with prednisolone, VCR and sirolimus has favorable tolerance and efficacy for life-threatening KMP. Once a stable condition has been achieved, cocktail therapy should be replaced by sirolimus monotherapy to reduce potential side effects.

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.

Rapamycin induces autophagy and apoptosis in Kaposiform hemangioendothelioma primary cells in vitro

BACKGROUND

Rapamycin has been recommended to treat Kaposiform hemangioendothelioma (KHE) with Kasabach-Merritt phenomenon (KMP), but the underlying mechanism of the clinical effect has not been established. Therefore, we determined rapamycin cytotoxicity on KHE cells in vitro and the underlying mechanism.

METHODS

KHE primary cells were derived from a tumor specimen and treated with rapamycin. Immunofluorescence was applied to identify the cells. Cell viability was measured using the Cell Counting Kit-8 (CCK-8) assay. Cell cycle and apoptosis were assessed using flow cytometry (FCM). Western blots (WB) were performed to determine phosphorylation of mammalian target of rapamycin (mTOR), p70 S6 kinase (S6K1), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), as well light chain 3 (LC3) expression.

RESULTS

Rapamycin inhibited the growth of KHE primary cells in a dose- and time-dependent manner. Cell cycle progression was arrested in the G0/G1 phase and apoptosis was induced. WB results showed that LC3-II/I expression was significantly elevated in KHE primary cells treated with rapamycin, while the level of p-mTOR, p-S6K1, and p-4E-BP1 expression was reduced. LC3 fluorescent spots were increased in the rapamycin treatment group.

CONCLUSIONS

Rapamycin inhibited KHE primary cell proliferation, induced apoptosis and autophagy, and blocked the mTOR signaling pathway.

Magnetic Resonance Imaging Evaluation of Hemangioma Resection for Encephalofacial Angiomatosis (Sturge-Weber Syndrome) in Children under Intelligent Algorithm

This study was aimed to evaluate the clinical efficacy of hemangioma resection in the treatment of infantile encephalofacial angiomatosis (Sturge–Weber syndrome, SWS) through magnetic resonance imaging (MRI) images, and intelligent algorithms were employed to process MRI images. A retrospective study of 45 children diagnosed with facial hemangioma admitted to hospital was conducted. Then, MRS images were acquired, and a mathematical model for MRI image denoising and reconstruction was constructed based on nonlocal similar block low-rank prior algorithms. The processing effect was assessed regarding the peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). Finally, MRI images were collected to analyze the difference between the metabolites of N-acetylaspartic acid (NAA), creatine (Cr), choline (Cho), and their ratios in the lesions of the children before and after treatment. The improvement rate was analyzed through a twelve-month follow-up. The algorithm test results showed that compared with the classic K-singular value decomposition (K-SVD) denoising algorithm and the Sparse MRI reconstruction algorithm, the proposed algorithm processed MRI images more clearly and had more detailed information. The quantitative results showed that the PSNR and SSIM in the image processed by the algorithm proposed were remarkably large. The clinical treatment results showed that compared with those before treatment, the nCho level after treatment, the ratio of Cho/Cr and Cho/NAA were remarkably reduced, and the difference was remarkable (P < 0.05). The follow-up results showed that the considerable improvement rate was 88.89%, the postoperative organ remodeling rate was 17.78%, and the probability of reoperation was only 6.67%. In summary, the introduction of intelligent algorithms for denoising and reconstruction of MRI images can remarkably improve image quality and help doctors use image information to diagnose diseases and evaluate treatment effects. The hemangioma resection for the treatment of pediatric SWS had a high treatment improvement rate and was worthy of clinical adoption.

Kaposiform hemangioendothelioma with fatal income: Kasabach-Merritt phenomenon and hypercalcemia

Kaposiform hemangioendothelioma is a rare, borderline tumor that typically occurs during early childhood. Kasabach-Merritt phenomenon is a complication characterized by a consumptive coagulopathy resulting from the localized intravascular coagulation. Hypercalcemia generation is a rare association that was related in our case to parathyroid hormone-related protein produced by this angioma.

Case report: Kaposi hemangioendothelioma of the right upper limb with the Kasabach-Merritt phenomenon: A potentially lethal diagnostic challenge

Kaposi hemangioendothelioma (KHE) is a rare vascular neoplasm that presents usually within the first year of life. Because of its rarity and complexity, there is often a delay in diagnosis. KHE could be associated with a life-threatening consumptive coagulopathy named the Kasabach-Merritt phenomenon (KMP). Here, we present the case of a 2-month-old girl who presented with progressive redness and swelling of her right upper limb over 6 weeks. Multiple health practitioners misdiagnosed her condition as an insect bite, cellulitis, and necrotizing fasciitis and gave treatment accordingly, which proved futile. A full blood count revealed bicytopenia of anemia and thrombocytopenia, a normal coagulation cascade, low fibrinogen, and raised D-Dimer levels. The imaging was suggestive of a high-flow vascular tumor likely to be a KHE. Subsequently, she was started on single-agent oral sirolimus with a dose increment to achieve satisfactory therapeutic levels and was treated for 1 year. She successfully completed the treatment regimen and had only transient hypertriglyceridemia, which resolved upon the completion of treatment. Currently, she is in remission 3 years after treatment. Keeping her case as an example, we would like to highlight the potentially lethal misdiagnosis of KHE with KMP, the importance of an early diagnosis of this condition, and the successful treatment outcome with single-agent sirolimus.

HEPATIC VASCULAR TUMORS IN CHILDREN: POTENTIAL RISKS, OPTIMAL IMAGING AND THE ROLE OF SURGICAL INTERVENTION

OBJECTIVE

The aim: To revise the case-series of hepatic vascular tumors (HVT), particularly to identify optimal visualization, management and role of surgical intervention.

PATIENTS AND METHODS

Materials and methods: Out of 96 children with hepatic tumors who hospitalized in a single center from 2011 to 2020, 20 (20,8%) were diagnosed HVT. Hepatic Hemangiomas (HHs) were presented in 19 patients and Kaposiform hemangioendotelioma (KHE) in one case. To determine the type of HH we used radiological classification. For visualisation contrast-enhanced MRI (n=7, 30%) and cCT (n=15,70%) were used. Follow-up period was 14-77 months.

RESULTS

Results: All HVT were revealed by sonogram at the age of 0-5 m, with 4 (20%) diagnosed prenatally. Male to female ratio was 3:2. Beta-blockers were prescribed to 12 patients with HHs. Treatment duration was from 6 to 24 month. Steroid therapy was initial in cases when it was impossible to prescribe the curative dose of beta-blockers. Complications of propranolol treatment were transitory bradycardia (n=7) and transitory hypoglycemia (n=2). After vincristine chemotherapy decreases the tumor size by 54%, that allowed a safe liver resection. 4 (20%) patients - two multifocal HHs, one diffuse HH and in patient with KHE manifested congestive heart failure and pulmonary hypertension Mortality rate is 5% (n=1), this patient died against progressive cardiovascular failure.

CONCLUSION

Conclusions: life-threatening complication of HVT was congestive heart failure. Early treatment is beneficial for complications prevention. Surgical treatment is optional for KHE when can be removed safely.

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.

Cutaneous Vascular Neoplasms of Uncertain Biological Behavior

Neoplasms of uncertain biological behavior present physicians with a genuine conundrum in practice. Cutaneous vascular neoplasms within this category are exceedingly rare, possessing significant gaps and uncertainty in many facets of clinical practice. Firstly, lesions were selected for review based on their categorization as indeterminate behavior, indicating the potential for local recurrence and rarely metastasize. After identification of the target lesions, a comprehensive review of the literature using national databases produced several landmark studies and case series regarding these neoplasms. Limiting the review to only cutaneous limited tumors narrowed the pool of studies; however, quite a large sum of papers remained. Examination of each paper yielded beneficial results on diagnosing, effective treatments, follow-up findings, and prognosis for each indeterminate lesion discussed. Overall, the literature search combined the molecular, histologic, immunohistochemical, surgical strategies to develop an up-to-date and comprehensive framework to guide physicians when encountering such lesions. The tumors reviewed include: kaposiform hemangioendothelioma, endovascular papillary angioendothelioma, pseudomyogenic hemangioendothelioma, retiform hemangioendothelioma, epithelioid hemangioendothelioma, and composite hemangioendothelioma.

Kaposiform haemangioendothelioma in an adult: lack of response to topical sirolimus and response to radiotherapy

Kaposiform haemangioendothelioma (KHE) is a rare, primarily paediatric tumour with only a handful of case reports in the adult population. Given the paucity of evidence, this article is important in raising awareness of radiotherapy as a suitable and effective treatment in the adult population with KHE and highlights the potential limitations of topical sirolimus in these tumours.

[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.

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.

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.

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.

Kaposiform Hemangioendothelioma: clinicopathological characteristics of 8 cases of a rare vascular tumor and review of literature

BACKGROUND

Kaposiform Hemangioendothelioma (KHE) is a rare vascular tumor of intermediate malignant potential which shows locally aggressive growth but only rarely metastasizes. It is mostly considered to be a tumor of pediatric population but its occurrence in the adults is not uncommon as once considered. Histologically, KHE can mimic other soft tissue neoplasms of different behaviors (e.g. Kaposi Sarcoma, hemangioma) and establishing the correct diagnosis is important for appropriate treatment. Herein, we describe the clinicopathological features of 8 cases of KHE which will be helpful in making their diagnosis.

METHODS

We reviewed pathology reports, microscopy glass slides and obtained follow up information about 8 cases of KHE which were diagnosed at our institution from January 2008 till June 2020. Immunohistochemical stain for HHV8 was also performed.

RESULTS

Age ranged from 7 months to 25 years. Seven patients were less than 20 years of age and one patient was 25 years old. Equal gender distribution was observed. Extremities were the most common sites of involvement, followed by head and neck, pancreas and ischiorectal region. 2 cases were resection specimen and all others were incisional biopsies. The largest tumor size was 5.5 cm in one of the resections. The incisional/fragmented tissues were all less than 5 cm in aggregate. Most cases showed predominance of nodular growth and a minor component of spindle cell population along with lymphangiomatosis like vascular channels, with evidence of microthrombi in 2 cases. Few multinucleated giant cells were observed in 2 cases. None of the cases exhibited significant nuclear atypia or mitotic activity. One of the cases arising in dermis showed underlying bone involvement. HHV8 was negative in 7/7 cases.

CONCLUSIONS

KHE can also involve adult population and it should always be considered in the differential diagnoses of a vascular lesion. Presence of multinucleated giant cells is a rare finding. Knowledge about histological features and potential mimics is helpful in avoiding misdiagnosis.

Kaposiform Hemangioendothelioma of the Oral Cavity: A Rare Tumor with an Unusual Location

Kaposiform hemangioendothelioma is a rare neoplasm with intermediate malignant behavior, mainly affecting infants and children. Involvement head and neck is uncommon, and there are only four cases reported in the oral cavity and oropharynx. Microscopically, it is characterized by a vascular proliferation permeated by spindle-to-ovoid cells resembling Kaposi sarcoma. Immunohistochemically, the tumor is positive for CD31, CD34 and negative for D2-40. Herein we present a rare case of intraoral Kaposiform hemangioendothelioma in a 10-year-old boy.

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.

Sirolimus for Kaposiform Hemangioendothelioma and Kasabach-Merritt Phenomenon in a Neonate

We present a case of a neonate born with kaposiform hemangioendothelioma (KHE), complicated by Kasabach-Merritt phenomenon (KMP) and other serious conditions, who was successfully treated with sirolimus. In addition to complications from thrombocytopenia and fluid overload, during the course of therapy, our patient experienced supratherapeutic drug levels at the commonly accepted starting dose of sirolimus. Patients with KHE and KMP should be closely monitored for potential complications of both the initial disease and unexpected side effects of treatments.

Kasabach-Merritt phenomenon with cellulitis in infant

Kasabach-Merritt phenomenon (KMP) is consumptive coagulopathy in large vascular lesion. This condition is specific in kaposiform haemangioendothelioma (KHE) and tufted angioma, associated with high mortality rate. This condition often involves the limbs, trunk and retroperitoneum. The clinical features that are usually found are purpura, oedema, induration and ecchymosis. A boy baby aged 9 months presented with a history of violaceous tumour that appeared on his left leg at birth that became enlarged since 6 months ago that caused discrepancy between both of his legs. The patient has his left leg massaged through alternative treatment, causing it became bruised and wounded. Blood examination showed normocytic normochromic anaemia with severe thrombocytopenia and high D-dimer. The patient was diagnosed with KMP with cellulitis and treated with oral corticosteroid, propranolol and antibiotics. Diagnosis of KMP can be made through clinical and laboratory findings. Combination therapy with corticosteroid and propranolol can be considered for KMP treatment.

Kaposiform hemangioendothelioma with overlapping features of rapidly involuting congenital hemangioma and a delayed complication of necrotizing fasciitis

We report the case of a male infant born at term with kaposiform hemangioendothelioma (KHE) of the right forearm and coagulopathy. Our case was unusual as it involuted leaving subcutaneous atrophy and prominent veins, which are more commonly observed in rapidly involuting congenital hemangioma. At 3 years of age, the child developed recurrent superficial thrombophlebitis localized to the area where the KHE had regressed. Subsequently, he developed necrotizing fasciitis and thrombotic veins in the same location and group A streptococcal septic shock.

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 in Adolescent-Onset Scoliosis: A Case Report and Review of Literature

Background and Objectives. Kaposiform hemangioendothelioma (KHE) is a vascular tumor of very low incidence, which occurs mostly in children and infants. The tumor is recognized for its locally aggressive, yet rarely metastatic behavior. It may cause consumptive coagulopathy known as Kasabach-Merritt phenomenon. We report a distinctive case, where an 11-year-old boy is presented with progressive thoracolumbar scoliosis without any symptom or neurological sign. Case Report. The patient underwent spinal deformity correction via posterior pedicle screw instrumentation and fusion, along with tumor biopsy. The pathology report confirmed KHE. The patient did not show a prominent progression of scoliosis after the surgery without any further treatments. Conclusions. Many of scoliotic patients do not have any apparent cause, thereby regarded as idiopathic scoliosis. The presented case is where kaposiform hemangioendothelioma is likely to be linked to the patient's scoliosis. We demonstrate the possibility of secondary scoliosis should always be kept in mind of orthopaedic doctors. We also conclude that secondary scoliosis does not show exacerbation after growth completion.

Kaposiform hemangioendothelioma and tufted angioma - (epi)genetic analysis including genome-wide methylation profiling

Kaposiform hemangioendothelioma (KHE) is a locally aggressive vascular condition of childhood and is clinicopathologically related to tufted angioma (TA), a benign skin lesion. Due to their rarity molecular data are scarce. We investigated 7 KHE and 3 TA by comprehensive mutational analysis and genome-wide methylation profiling and compared the clustering, also with vascular malformations. Lesions were from 7 females and 3 males. The age range was 2 months to 9 years with a median of 10 months. KHEs arose in the soft tissue of the thigh (n = 2), retroperitoneum (n = 1), thoracal/abdominal (n = 1), supraclavicular (n = 1) and neck (n = 1). One patient presented with multiple lesions without further information. Two patients developed a Kasabach-Merritt phenomenon. TAs originated in the skin of the shoulder (n = 2) and nose/forehead (n = 1). Of the 5 KHEs and 2 TAs investigated by DNA sequencing, one TA showed a hot spot mutation in NRAS, and one KHE a mutation in RAD50. Unsupervised hierarchical clustering analysis indicated a common methylation pattern of KHEs and TAs, which separated from the homogeneous methylation pattern of vascular malformations. In conclusion, methylation profiling provides further evidence for KHEs and TAs potentially forming a spectrum of one entity. Using next generation sequencing, heterogeneous mutations were found in a subset of cases (2/7) without the presence of GNA14 mutations, previously reported in KHE and TA.

Tufted angioma with associated Kasabach-Merritt phenomenon caused by somatic mutation in GNA14

Tufted angioma (TA) is a rare vascular tumor characterized by histologic tufts of proliferating capillaries that occurs in infancy or early childhood, with a poorly understood pathogenesis. Though benign, TA can be associated with the Kasabach-Merritt phenomenon (KMP), a life-threatening consumptive coagulopathy and thrombocytopenia. Here, we explored the genetic mechanism underlying a case of TA associated with KMP via targeted sequencing of laser capture micro-dissected lesion and blood DNA, and identified a somatic, activating GNA14 mutation specific to the tumor. Our findings support aberrant GNA14 activation underlies the pathogenesis of TA associated with KMP.