Kaposiform haemangioendothelioma: a review with emphasis on histological differential diagnosis

Construction and applications of the EOMA spheroid model of Kaposiform hemangioendothelioma

BACKGROUND

Kaposiform hemangioendothelioma (KHE) is a rare intermediate vascular tumor with unclear pathogenesis. Recently, three dimensional (3D) cell spheroids and organoids have played an indispensable role in the study of many diseases, such as infantile hemangioma and non-involuting congenital hemangiomas. However, few research on KHE are based on the 3D model. This study aims to evaluate the 3D superiority, the similarity with KHE and the ability of drug evaluation of EOMA spheroids as an in vitro 3D KHE model.

RESULTS

After two days, relatively uniform morphology and high viability of EOMA spheroids were generated by the rotating cell culture system (RCCS). Through transcriptome analysis, compared with 2D EOMA cells, focal adhesion-related genes such as Itgb4, Flt1, VEGFC, TNXB, LAMA3, VWF, and VEGFD were upregulated in EOMA spheroids. Meanwhile, the EOMA spheroids injected into the subcutaneous showed more obvious KMP than 2D EOMA cells. Furthermore, EOMA spheroids possessed the similar characteristics to the KHE tissues and subcutaneous tumors, such as diagnostic markers (CD31 and LYVE-1), cell proliferation (Ki67), hypoxia (HIF-1α) and cell adhesion (E-cadherin and N-cadherin). Based on the EOMA spheroid model, we discovered that sirolimus, the first-line drug for treating KHE, could inhibit EOMA cell proliferation and downregulate the VEGFC expression. Through the extra addition of VEGFC, the effect of sirolimus on EOMA spheroid could be weakened.

CONCLUSION

With a high degree of similarity of the KHE, 3D EOMA spheroids generated by the RCCS can be used as a in vitro model for basic researches of KHE, generating subcutaneous tumors and drug screening.

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.

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 of the thigh: A case report

Kaposiform hemangioendothelioma is a rare, locally aggressive or borderline vascular tumor that typically affects infants. It presents as a purpuric cutaneous lesion and may be associated with life-threatening coagulation disorders, such as the Kasabach-Merritt phenomenon. The differential diagnosis can be challenging based on clinical presentation alone. Imaging plays a crucial role in the diagnostic workup, particularly magnetic resonance imaging. We present a case report of a 4-month-old patient with an enlarging vinous cutaneous mass on the thigh and coagulation abnormalities. Magnetic resonance imaging revealed a large, infiltrative, soft-tissue lesion with poorly defined margins and heterogeneous enhancement, that involved all muscle compartments of the thigh and was associated with lymphedema, stranding of the subcutaneous fat and cutaneous thickening. These findings were consistent with kaposiform hemangioendothelioma of the thigh and the diagnosis was confirmed by histopathological characterization.

Laparoscopic cholecystectomy for symptomatic cholecystolithiasis (CCL) in "Kasabach-Merritt syndrome" (KMS) (Kaposi-tumor like hemangioendothelioma with case-specific perioperative management)

Objectives

The Kasabach-Merritt syndrome (KMS) is characterized by the occurrence of hemangioendothelioma (giant hemangioma with thrombosis leading to thrombocytopenia), which can be associated with disseminated intravasal coagulation. Specific aim: Based on (i) selective references from the current scientific literature and derived recommendations as well as (ii) own experiences obtained in the diagnostic and perioperative management of a representative case from daily practice in abdominal surgery, the specific case undergoing elective cholecystectomy (CCE) in KMS is to be described by means of scientific case report.

Case presentation

(Patient-, finding- and treatment-specific characteristics): - Medical history: 72-years old female patient with a known KMS of the left arm and upper thorax, recurrent thrombophlebitis of the left arm and thoracic veins, previous upper GI bleeding (Mallory-Weiss syndrome in 2006, chronic anemia in lack of vitamin B12, type-A gastritis, former bleeding complications after teeth extraction/open appendectomy 1962/Caesarean section 1968 with need of transfusion [60 red blood cell packages]), intraabdominal adhesions, hypothyreosis, initial liver cirrhosis. - Symptomatology: Characteristic for cholecystolithiasis (CCL). - Diagnostic: Abdominal ultrasound shows CCL, fibroscan does not confirm suspicious cirrhosis. Laboratory parameters showed: Activation of intravasal coagulation with elevated prothrombin fragments, D-dimers and reduced antiplasmin concentration. Accelerated fibrinolysis capacity; currently, no secondary thrombocytopenia or factor-13 decrease. In addition, fibrinogen concentration within normal range, no hint onto the manifestation of an aquired von-Willebrand's syndrome. - Diagnosis: Chronic fibrosing cholecystitis in CCL after former acute cholecystitis (3 months ago) with indication for surgical intervention. - Therapy: Laparoscopic CCE including careful exploration of upper abdominal cavity for KMS manifestation (with no revision of bile duct) and peritoneal adhesiolysis (histological finding, chronic fibrosing cholecystitis with thickening of the wall of the gall bladder but no hint of malignancy) under perioperative prophylaxis with antibiotics and temporary cessation of platelet medication for 7 d preoperatively, "bridging" with low molecular weight heparin (Clexane, 1 × 40 mg s.c.; Sanofi-Aventis, Frankfurt/Main, Germany); 1 h preoperatively, 15-20 mg/kg body weight Cyclocapron i.v. (once again 6-8 h postoperatively; thereafter, 500 mg of Cyclocapron 4×/d until the 3rd postoperative day). - Intraoperatively: Congestion of veins but not at the immediate surgical field (gall bladder, hepatic bed of the gall bladder, Calot's triangle). - Outcome: Uneventful, in particular, no (bleeding) complications.

Conclusions

If surgical approach is indicated, the intervention should be thoroughly planned (in particular, under elective circumstances) with regard to hemangioma site and extension as well as distance to the surgical field and possible surgical alternative options (surgical access site, open/laparoscopic approach etc.) to prevent - at the best possible rate - bleeding complications intra-/postoperatively and, thus, to provide adequate patient safety.

Novel organoid construction strategy for non-involuting congenital hemangioma for drug validation

BACKGROUND

Non-involuting congenital hemangiomas (NICHs) are fully formed vascular tumors at birth with distinctive clinical, radiologic, and histopathological profiles. In the literature, there is no effective therapy strategy for patients with NICH except surgery. Currently, no cell line or animal model exists for studying the mechanism of NICH and drug validation. We plan to construct a new strategy by constructing NICH organoids for further study.

RESULT

Here, we report a novel NICH organoid system construction and optimization process. Both HE and immunohistological staining exactly matched NICH tissue. We further performed transcriptome analysis to elucidate the characteristics of NICH organoids. Both NICH tissue and NICH organoids manifested similar trends in download sites. NICH organoids display novel features to new cells derived from organoids and show spectacular multiplication capacity. In the preliminary verification, we found that cells splitting from NICH organoids were human endothelial cells. Drug validation demonstrated that trametinib, sirolimus, and propranolol showed no inhibitory effects on NICH organoids.

CONCLUSION

Our data show that this new NICH-derived organoid faithfully captured the features of this rare vascular tumor. Our study will boost further research on the mechanism of NICH and drug filtering in the future.

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.

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.

MRI-based radiomics in distinguishing Kaposiform hemangioendothelioma (KHE) and fibro-adipose vascular anomaly (FAVA) in extremities: A preliminary retrospective study

OBJECTIVE

To investigate the pretreatment differentiation between Kaposiform hemangioendothelioma (KHE) and fibro-adipose vascular anomaly (FAVA) in extremities of pediatric patients. To build and validate an MRI-based radiomic model.

METHOD

In this retrospective study, we obtained imaging data from 43 patients. We collected and compared clinical information, sketched region of interest (ROI), and extracted radiomic features from fat-suppressed T2-weighted (T2FS) images of the two cohorts of 30 and 13 patients respectively (training versus testing cohort 7:3). To select features, we used two sample t-test and the least absolute shrinkage and selection operator (LASSO) regression. The support vector machine (SVM) classification was constructed and evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

Thirty patients with KHE and 13 patients with FAVA in the extremities were included. Most lesions demonstrated low to intermediate signal intensity on T1-weighted images and hyperintense signals on T2-weighted ones. They also showed similar traits pathologically. Initially, 107 radiomic features were acquired and then three were finally selected. The support vector machine (SVM) model was able to differentiate the two anomalies from each other with an area under the curve (AUC) of 0.807 (95%CI 0.602-1.000) and 0.846 (95%CI 0.659-1.000) in training and testing cohort, respectively.

CONCLUSION

The derived radiomic features were helpful in differentiating KHE from FAVA. A model which contained these features might further improve the performance and hopefully could serve as a potential tool for identification.

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.

Vascular anomalies: clinical perspectives

Vascular anomalies are classified as vascular tumors or vascular malformations according to their cellular features and biological behavior. Detailed history and clinical assessment allow for the proper clinical diagnosis of most vascular anomalies and guide the choice of imaging to evaluate them. This article discusses the general information needed from a clinical history and physical exam to formulate a diagnosis of vascular anomaly. Then, the authors review the clinical findings from the most common vascular tumors and vascular malformations.

Genetic context of oncogenic drivers dictates vascular sarcoma development in aP2‐Cre mice

Angiosarcomas are aggressive vascular sarcomas that arise from endothelial cells and have an extremely poor prognosis. Because of the rarity of angiosarcomas, knowledge of molecular drivers and optimized treatment strategies is lacking, highlighting the need for in vivo models to study the disease. Previously, we generated genetically engineered mouse models of angiosarcoma driven by aP2‐Cre‐mediated biallelic loss of Dicer1 or conditional activation of Kras^G12D with Cdkn2a loss that histologically and genetically resemble human tumors. In the present study, we found that DICER1 functions as a potent tumor suppressor and its deletion, in combination with either KRAS^G12D expression or Cdkn2a loss, is associated with angiosarcoma development. Independent of the genetic driver, the mTOR pathway was activated in all murine angiosarcoma models. Direct activation of the mTOR pathway by conditional deletion of Tsc1 with aP2‐Cre resulted in tumors that resemble intermediate grade human kaposiform hemangioendotheliomas, indicating that mTOR activation was not sufficient to drive the malignant angiosarcoma phenotype. Genetic dissection of the spectrum of vascular tumors identified genes specifically regulated in the aggressive murine angiosarcomas that are also enriched in human angiosarcoma. The genetic dissection driving the transition across the malignant spectrum of endothelial sarcomas provides an opportunity to identify key determinants of the malignant phenotype, novel therapies for angiosarcoma, and novel in vivo models to further explore angiosarcoma pathogenesis. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Primary Kaposiform Hemangioendothelioma of the Humerus: A Case Report

Kaposiform hemangioendothelioma (KHE) is a neoplasm originating mainly from vessels and has a mild proclivity for malignancy. This neoplasm mainly involves somatic soft tissue and retroperitoneum. Histological findings include a nodular arrangement of oval-to-spindle cells containing pale cytoplasm. Vascular spaces are in the form of slit-like channels in which red blood cells are evident. Here, we report the case of a two-year-old male who presented with Erb’s palsy and a mass lesion in the right humerus. Tissue biopsy features were compatible with KHE.

Comparison of Effectiveness of Two Different Doses of Propranolol on Kaposiform Hemangioendothelioma

OBJECTIVE

To compare the clinical efficacy and safety of two different doses of propranolol in the treatment of cutaneous kaposiform hemangioendothelioma (KHE).

METHODS

The cohort of this prospective case-control study comprised 11 children with KHE treated from October 2015 to August 2018 in our institution. All participants were clinically and pathologically diagnosed as having cutaneous KHE. The children were allocated to two groups: six children in Group A (low-dose group) received oral propranolol 1.5 mg/kg/d, whereas five in Group B (high-dose group) received oral propranolol 2 mg/kg/d. The children were checked and photographed before and after treatment. Changes in the tumors were tracked by clinical and ultrasound examination. Follow-up visits to monitor for adverse reactions occurred regularly.

RESULTS

Grade I, Grade II, and Grade IV improvements in tumors were each noted in one child in Group A (three improved in total) and Grade III in two and Grade IV in another two children in Group B (four improved in total). Oral propranolol was effective in 50 and 80% of children in Groups A and B, respectively; this difference is statistically significant (P < 0.01). Minor adverse reactions occurred in eight of the 11 children.

CONCLUSIONS

Propranolol treatment is effective against cutaneous KHE. There were no serious adverse reactions, and the treatment was safe in the long term. A dose of 2 mg/kg/d was more effective than 1.5 mg/kg/d in the treatment of KHE and did not increase the rate of adverse reactions. Children with KHE should be treated with propranolol 2 mg/kg/d orally.

Solid pancreatic masses in children: A review of current evidence and clinical challenges

Pancreatic tumors in children are infrequently encountered in clinical practice. Their non-specific clinical presentation and overlapping imaging characteristics often make an accurate preoperative diagnosis difficult. Tumors are categorized as epithelial or non-epithelial, with epithelial tumors further classified as tumors of the exocrine or endocrine pancreas. Although both are tumors of the exocrine pancreas, solid pseudopapillary neoplasm is the most prevalent solid pancreatic tumor in children, while pancreatoblastoma is the most common malignant tumor. Insulinoma is the most common pediatric pancreatic tumor of the endocrine pancreas. Malignant tumors require a complete, often radical, surgical resection. However, pancreatic parenchyma-sparing surgical procedures are utilized for benign tumors and low-grade malignancy to preserve gland function. This review will discuss the epidemiology, pathophysiology, clinical and diagnostic characteristics, and management options associated with both common and rare solid pancreatic masses in children. We will also discuss current challenges encountered in their evaluation and treatment.

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.

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 haemangioendothelioma: magnetic resonance imaging features in 64 cases

Background

Kaposiform haemangioendothelioma (KHE) is a rare, locally aggressive disorder. The presenting and imaging features of KHE can overlap with other vascular anomalies and tumours. We aimed to analyse the imaging findings of KHE disorder and highlight features most suggestive of this diagnosis.

Methods

The clinical features and imaging findings were retrospectively reviewed in 64 patients with pathological diagnosis of KHE.

Results

Of the 64 patients diagnosed with KHE, 36 patients were < 6 months and 28 patients were ≥ 6 months. The most common presenting features were Kasabach-Merritt phenomenon (KMP, 42.2 %), visible cutaneous lesions (90.6 %), oedema or swelling (43.8 %) and destructive changes or remodelling of adjacent bone (42.2 %). Compared with patients in the group ≥ 6 months, patients in the group < 6 months have higher odds of KMP (P = 0.000), infiltrative lesion with ill-defined borders (P = 0.044). The group ≥ 6 months have higher odds of destructive changes or remodelling of adjacent bone (P = 0.002). In all patients, the lesions in all of the 64 patients were hypointense or isointense compared with muscle on T1-weighted sequences, and hyperintense on T2-weighted or inversion-recovery sequences, nine patients (14.1 %) showed vascularity. There were 28 patients (43.8 %) with characteristic enhancing and infiltrative soft-tissue thickening.

Conclusions

Presence of visible cutaneous lesions with ill-defined borders, destructive changes or remodelling of adjacent bone, severe thrombocytopenia and consumptive coagulopathy should favour the diagnosis of KHE.

Kaposiform haemangioendothelioma of duodenum in a neonate

Kaposiform haemangioendothelioma, an endothelial borderline tumour, is typically seen in childhood involving extremities. It has been closely associated with a consumptive coagulopathy state, Kasabach-Merritt phenomenon (KMP). Extracutaneous involvement is uncommon. Intestinal involvement is quite uncommon and can masquerade as an acute abdomen. A 24-day-old neonate presented with bilious vomiting and fever for 5 days. Sections from the resected gangrenous duodenum contained a submucosal tumour composed of infiltrating nodules of slit-like or crescentic CD34-positive spindled-to-flattened endothelial-lined vascular spaces along with zones of fibrosis. No nuclear pleomorphism or necrosis identified. The findings were classic example of kaposiform haemangioendothelioma with an absence of any deranged coagulation profile. The index case raises interest given its congenital incidental presentation at an uncommon site, like duodenum, and absence of coexistent KMP.

Vascular tumors of the mediastinum

Vascular tumors represent only a sliver of all tumors affecting the mediastinum, but they pose diagnostic challenges due to significant overlap among entities, ever-evolving classification schemes, and the exquisite rarity of some of the entities not only in the mediastinum but in pathology practice as a whole. Most of the vascular tumors are better known to the practice of soft tissue pathology, from which some of the knowledge of clinical behavior can be extrapolated. For example, the stratification of epithelioid hemangioendothelioma (EHE) into two biologically separate categories has effectively translated from the somatic soft tissues to the thorax. For other entities, the effective validation of soft tissue parameters is hindered by the small numbers of reported mediastinal cases. Many of the treatment modalities have also transferred over, with the key differences resting on the difficulty in achieving complete surgical resection for mediastinal tumors as opposed to those in the somatic soft tissues. Accordingly, systemic drug therapies have emerged as attractive options for some of the mediastinal vascular tumors, such as kaposiform hemangioendothelioma (KHE) and Kaposi sarcoma (KS). The categories presented herein mirror the classification scheme set forth by the 5th Edition WHO Classification of Soft Tissue and Bone Tumors. This review focuses on the biologically aggressive vascular neoplasms while limiting discussion of the benign entities to relevant comparisons in the differential diagnoses. While distinguishing among the benign entities has academic importance, in practice, the stakes are far higher for diagnosing the biologically aggressive tumors given their marked heterogeneity in clinical outcomes. Practical advice for problem areas in pathology will be reviewed alongside tumor pathobiology, including the latest in molecular diagnostics.

Sirolimus for Kaposiform Hemangioendothelioma With Kasabach-Merritt Phenomenon in Two Infants

Kaposiform hemangioendothelioma is an aggressive vascular tumor with infiltrative growth that commonly occurs in infancy and is associated with a life-threatening consumptive coagulopathy, as well as Kasabach-Merritt phenomenon. Recently, promising results have shown that sirolimus had been successfully used to treat Kasabach-Merritt phenomenon without significant toxicity. However, the situation the authors encountered in treating infants was not so satisfactory. Here, the authors present 2 patients younger than 3 months with refractory Kaposiform hemangioendothelioma treated with sirolimus and experienced severe pneumonia. The outcomes suggest that it is necessary to keep an eye on any symptoms indicate the infection of respiratory tract and use the antibiotics in time. The 2 cases also remind us of the potential sign that indicate the recurrence of KMP, which refers to firmer lesion with deepen color, especially when it comes with complications.

Soft Tissue Special Issue: Perivascular and Vascular Tumors of the Head and Neck

Perivascular and vascular neoplasms of the head and neck are a rare group of tumors comprising a spectrum of clinical/biologic and histological features. They are frequently diagnostically challenging, due to their morphologic and immunohistochemical overlap. In this review, we summarize the pathology of these neoplasms, discussing morphology, immunohistochemistry, associated genetic findings, and the differential diagnoses.

Congenital haemangiomas: a single-centre retrospective review

OBJECTIVE

Congenital haemangiomas (CHs) are rare, benign vascular tumours that are fully developed at birth. Three subtypes of CHs have been described based on clinical behaviour: rapidly involuting CHs (RICHs), non-involuting CHs (NICHs) and partially involuting CHs (PICHs). We explore in our study clinical, evolutionary and paraclinical characteristics of the three CH subtypes.

DESIGN

Children with CH attending our department of paediatric dermatology at Bordeaux University Hospital over a 13-year period were retrospectively included. Epidemiological, clinical and evolutionary data, photographs and imaging results were reviewed. All available tissue samples were histologically examined.

RESULTS

We included 57 patients: 22 with RICH, 22 with NICH and 13 with PICH. Males predominated (ratio 1.7); the most common CH location was on the limbs. RICH, NICH and PICH exhibited overlapping characteristics; all were single telangiectatic lesions with pale peripheral halos. At birth, NICHs were flat but RICHs and PICHs bulky. The median age at complete RICH involution was 12 months. One-third of CHs that appeared RICH-like at birth underwent incomplete involution to become PICHs. Heart failure and thrombocytopenia were rare complications. PICHs were frequently ulcerated. Pain was common for NICH and PICH. The imaging and histological data of the three CH subtypes were rather similar.

CONCLUSIONS

We describe the characteristics and evolution of the three CH subtypes using a case series. Certain overlapping features were apparent, reinforcing the hypothesis that RICH, NICH and PICH lie on the same pathological spectrum.

Childhood Vascular Tumors

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

Kaposiform 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.

[Infantile haemangioma: an update]

Infantile haemangioma (IH) are the most frequent skin tumors in childhood. The diagnosis is usually established from the clinical picture and typical course of growth. Sectional imaging procedures are indicated in segmental, especially facial haemangiomas. The vast majority of IH are uncomplicated and do not require any treatment. In complicated IH, treatment should be initiated as soon as possible in order to avoid permanent damage. Propranolol is the treatment of choice for complicated IH.

Vascular tumors in infants and adolescents

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

Peritoneal cavernous hemangiomatosis: A case report

BACKGROUND

Cavernous hemangiomatosis in the liver and spleen has been reported, but it occurs less commonly in the peritoneum. Here we report a case of peritoneal cavernous hemangiomatosis and share some valuable information about this disease.

CASE SUMMARY

A 57-year-old Chinese man had a huge abdominal mass with abdominal distention and a significant reduction of food consumption. An enhanced abdominal and pelvic computed tomography and positron emission tomography–computed tomography revealed multiple cystic masses on the peritoneum, greater omentum, small intestinal mesentery and the surface of the spleen, and a high maximum standardized uptake value of the largest cystic lesion. Exploratory laparotomy was performed, and multiple cystic masses were found on the surface of the peritoneum, greater omentum, mesentery of the small intestine, and surface of the liver and spleen. Dark red bloody cystic fluid was present in the cystic tumor. Pathological examination showed that in the stromal components, the irregular vascular wall was thin. The vessel lumen was interlinked, and the lumen was lined with flat endothelium. According to the intraoperative findings and pathologic results, the patient was diagnosed with peritoneal cavernous hemangiomatosis.

CONCLUSION

The possibility of peritoneal cavernous hemangiomatosis should be considered when multiple cystic masses are found in the abdominal cavity by preoperative examination.

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

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

Topical rapamycin (sirolimus) for the treatment of uncomplicated tufted angiomas in two children and review of the literature

The mTOR inhibitor rapamycin is used systemically for the treatment of vascular lesions. We report the first use of topical rapamycin for the successful treatment of two cases of tufted angioma. The evidence for the use of topical rapamycin in other dermatologic conditions is summarized to aid in clinical decision making on preparations and anticipated side effects.

Nonepithelial Tumors and Tumor-like Lesions of the Skin and Subcutis in Children

This overview of mesenchymal tumors presenting in the skin and/or subcutis in children brings together the range of neoplasms and hamartomas which are seen in this age-group. It is not surprising from the perspective of the pediatric or general surgical pathologist that vascular anomalies, including true neoplasms and vascular malformations, are the common phenotypic category. Since there is considerable morphologic overlap among these lesions, clinicopathologic correlation may be more important than for many of the other mesenchymal tumors. The skin and subcutis are the most common sites of clinical presentation for the infantile myofibroma which is the most common of fibrous mesenchymal tumors in children. Several of the other mesenchymal tumors are more common adults-like dermatofibrosarcoma protuberans, but nonetheless have an important presence in children, even as a congenital neoplasm. A lipomatous tumor in a young child should be considered as a possible manifestation of an overgrowth syndrome.

[Vascular anomalies. Part I: vascular tumors]

Vascular anomalies represent a spectrum of structural disorders and inborn errors of vascular morphogenesis, which may affect the entire arterial and venous vascular tree. They are divided into two major categories: tumors, which exhibit endothelial hyperplasia and malformations, which have normal endothelial turnover unless disturbed. Depending on their nature and complexity they can range from a simple "birthmark" to life-threatening entities. The relatively low incidence (4-10%) of vascular anomalies among the general population combined with the fact that their management often falls within the purview of several different medical and surgical specialties, has traditionally resulted in insufficient expertise in the management of these conditions. Therefore, accurate identification, a uniform nomenclature and a multidisciplinary approach are paramount for correct management.