Overexpression Prox1 in HemECs resembles Kaposiform hemangioendothelioma and cytotoxicity of sirolimus in vitro

BACKGROUND

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor that occurs in children. Prox1 is a specific lymphatic marker for KHE. We intended to establish a Prox1 transgenic cell line resembling KHE and investigate the mechanism of sirolimus in treating KHE.

METHODS

Prox1 was stably expressed in infantile hemangioma cell HemECs. RT-qPCR and Western blot were conducted to measure the expression of target genes. CCK-8, EdU assay, and cell cycle analysis were conducted to detect cell proliferation. Wound healing and transwell assay were used to evaluate cell migration and invasion.

RESULTS

Both mRNA and protein levels of Prox1, LYVE-1, Podoplanin were upregulated in Prox1⁺ HemECs. An acceleration of cell growth and a rise in migration and invasion were observed with Prox1 overexpression. Sirolimus inhibited cell proliferation, promoted apoptosis and led to G1 phase arrest in Prox1⁺ HemECs. The expression of p-mTOR, p-4EBP1, and p-P70S6K decreased and the ratio of LC-3 II/LC-3 I elevated after treatment of sirolimus.

CONCLUSIONS

Stable overexpression of Prox1 in HemECs induced a lymphatic endothelial reprogramming, and enhanced aggressive biological effects, partly resembled the invasion of KHE, and could serve as a novel model for KHE. Sirolimus may block mTOR-mediated pathways and induced autophagy in KHE.

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.

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.

Vascular Anomalies of the Head and Neck: A Pediatric Overview

Vascular anomalies, further classified into vascular tumors and malformations, often involve the head and neck region of children. These entities may raise diagnostic dilemmas, as they often demonstrate heterogenous and overlapping histologic features. The aim of this paper is to provide an overview of the common vascular anomalies in the head and neck region of children. Specific entities discussed include infantile hemangioma, congenital hemangioma, tufted angioma, kaposiform hemangioendothelioma, and various vascular malformations. Clinicopathologic features and associated molecular associations are reviewed.

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.

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.

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.

Vascular tumors

Vascular tumors are a rare subset of vascular anomalies. These are classified based on their malignant potential or local destruction potential. Classification has been historically difficult and treatment recommendations are based on case series. The purpose of this chapter is to review the presentation, pathologic and imaging characteristics. Treatment recommendations are summarized based on the current literature. Congenital and infantile hemangiomas are covered separately in a separate chapter in this issue.

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

Background

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

Case presentation

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

Conclusions

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

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.

Immunohistochemical Analysis of mTOR Pathway-Related Proteins in Kaposiform Hemangioendothelioma

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

A not so harmless mass: Kaposiform hemangioendothelioma complicated by a Kasabach-Merritt phenomenon

A vascular mass localized in the face and the neck was displayed by ultrasonography in a 38-week-old male fetus. At birth, the mass was bulky and purplish. The newborn breathed spontaneously but with severe desaturation. During laryngoscopy, we observed an obstruction of the larynx with a left-shift caused by the hemorrhagic mass. Blood analysis revealed anemia, severe thrombocytopenia, and coagulation disorders. The diagnosis of kaposiform hemangioendothelioma (KHE) complicated by a Kasabach-Merritt phenomenon (KMP) was put forward and treatment with propranolol, corticoids, and vincristine was initiated. Platelets were transfused daily for 8 days but did not resolve the thrombocytopenia. At day 8, we added sirolimus to the treatment and noted a rapid response with the normalization of the platelet count within 1 week and a significant regression of the mass. In this paper, we review the clinical and biological features of hemangioendothelioma associated with KMP and discuss its current and future treatment. Sirolimus seems to be very promising.

Kaposiform lymphangiomatosis and kaposiform hemangioendothelioma: similarities and differences

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Our experience with sirolimus for the treatment of complicated vascular anomalies]

AIM OF THE STUDY

mTOR inhibitors are being used to treat complex vascular anomalies (VA) without response to conventional treatments. We report our results in pediatric patients treated with sirolimus.

METHODS

Retrospective review of patients treated with sirolimus between 2014 and 2017, analyzing vascular anomaly type, treatment response and complications. Treatment protocol included patients with complex vascular anomalies, after signing the informed consent. The initial dose was 0.8 mg/m2/12 h, verifying plasmatic levels. Favorable response was defined both in clinical and radiological terms.

MAIN RESULTS

Sirolimus was employed in nine patients, median age 14 months old (1 month-14 years), 66% girls. Five complex micro-cystic lymphatic malformations (LM), one multifocal lynphangioendotheliomatosis with thrombocytopenia, one kaposiform lymphangiomatosis, one lymphatic-venous malformation and one kaposiform hemangioendothelioma (KHE) were treated. Median treatment was 4 months (IQR 2-18 months). Resolution or improvement was objectified in four patients (44%). KHE patient presented complete resolution after two months of treatment. Two patients with micro-cystic LM and the one with lymphatic-venous malformation improved after a median treatment of three months. Two patients presented rebound effect after discontinuing treatment. Three patients had hypertransaminasemia and hypercholesterolemia without requiring medical treatment.

CONCLUSION

Sirolimus presented mild effects for treatment of complex VA in our study, but was highly resolutive at KHE.

Kaposiform hemangioendothelioma without cutaneous involvement

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Congenital Vascular Tumors

Vascular tumors are benign neoplasms, which result from proliferating endothelial cells. These lesions present during infancy or childhood, may affect any location, and exhibit postnatal growth. Local complications include bleeding, tissue destruction, and pain whereas systemic sequelae include thrombocytopenia, congestive heart failure, and death. Vascular tumors should be differentiated from vascular malformations, which present at birth, have a quiescent endothelium, and grow in proportion to the child. Together, vascular tumors and malformations comprise the field of vascular anomalies.

Atypically presenting kaposiform hemangioendothelioma of the knee: ultrasound findings

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor of early childhood and infancy. Kasabach-Merritt phenomenon, a common complication of KHE, is characterized by life-threatening thrombocytopenia, hemolytic anemia, and consumption coagulopathy. There may be atypical cases that do not present with Kasabach-Merritt phenomenon and do have atypical imaging findings. Knowledge of atypical imaging features may assist radiologists in identifying KHE. In this report, we present a 4-year-old case of KHE with atypical ultrasound findings.

Histopathology of Spindle Cell Vascular Tumors

Vascular tumors with a spindled morphology represent a diagnostic challenge in soft tissue pathology. It may be difficult to distinguish certain benign entities in this category from spindled vascular tumors of intermediate malignancy or even spindled variants of angiosarcoma. This article focuses on vascular tumors characterized by a predominantly spindled morphology, including spindle cell hemangioma, acquired tufted angioma (angioblastoma of Nakagawa), kaposiform hemangioendothelioma, Kaposi sarcoma, and spindle cell variants of angiosarcoma.

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

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

Angiopoietins as serum biomarkers for lymphatic anomalies

Vascular anomalies can cause significant morbidity and mortality. Advances in diagnosis will be improved if noninvasive biomarkers can be identified, as obtaining a tissue biopsy can worsen the disease and precipitate complications. The goal of this study was to identify biomarkers for vascular anomaly patients to aid diagnosis and potentially give insights into pathogenesis. Blood was collected at baseline and then 6 and 12 months after treatment with the mTOR inhibitor sirolimus. Patients groups included generalized lymphatic anomaly (GLA), kaposiform lymphangiomatosis (KLA) and kaposiform hemangioendothelioma (KHE) with or without the Kasabach-Merritt phenomenon (KMP) coagulopathy. Serum was obtained from healthy controls selected to match the age and sex of the patients (21 days-28.5 years; 42% males; 58% females). Angiogenic and lymphangiogenic factors (VEGF-A, C, D, Ang-1 and Ang-2) were measured in serum using ELISA. In lymphatic anomaly patients, baseline levels of VEGF-A and VEGF-D were not different compared to controls. Angiopoietin-2 (Ang-2) levels were near controls levels in GLA patients but 10-fold greater in KLA patients and 14-fold greater in KHE patients when the KMP coagulopathy was present but not when it was absent. VEGF-C and angiopoietin-1 (Ang-1) levels were lower in KHE patients with KMP. Our analyses suggest that Ang-2 and Ang-1 can be used as biomarkers to help identify KLA and KHE patients with KMP coagulopathy with high sensitivity and specificity. After 12 months of sirolimus treatment, Ang-2 levels were lower in KLA and KHE with KMP patients compared to baseline levels and with most patients showing a clinical response. Hence, serum Ang-2 and Ang-1 levels may help in the diagnosis of patients with lymphatic anomalies and are concordant to sirolimus response.

Adult-onset Kaposiform hemangioendothelioma of the tongue: case report and review of the literature

We present here a very rare clinical case of a 38-year-old man with Kaposiform hemangioendothelioma (khe) of the tongue who presented to our institution with a growth under the left side of the tongue with no pain or discomfort. There were no enlarged lymph nodes and no significant neurologic findings. Diagnostic histopathology confirmed the lesion to be khe. The tumour was removed surgically, and the surgical specimen confirmed the diagnosis. Follow-up at 3 months shows no clinical evidence of recurrence.

Response to Paclitaxel in an Adult Patient with Advanced Kaposiform Hemangioendothelioma

BACKGROUND

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

CASE PRESENTATION

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

CONCLUSIONS

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

Neonatal kaposiform hemangioendothelioma of the spleen associated with Kasabach-Merritt phenomenon

Kaposiform hemangioendothelioma is a rare locally aggressive vascular tumor that usually manifests during early childhood. Typically the lesion presents with skin, soft tissue and bone involvement and is characterized histologically by ill-defined nodularity and the presence of spindle cells with resemblance to Kaposi's sarcoma. We report a rare neonatal case of a splenic kaposiform hemangioendothelioma associated with Kasabach-Merritt phenomenon that was diagnosed with radiographic imaging. Because of the rapid onset of thrombocytopenia and anemia, the patient required urgent splenectomy with subsequent resolution of the blood dyscrasias.