Vascular tumors of intermediate malignancy: An update.

The term "hemangioendothelioma" is used for endothelial neoplasms of intermediate malignancy and describes a group of rare neoplasms having biologic behavior falling in between that of the benign hemangiomas and fully malignant angiosarcomas. The hemangioendotheliomas fall into several specific, clinicopathologically and genetically distinct entities, specifically epithelioid hemangioendothelioma, kaposiform hemangioendothelioma, papillary intralymphatic angioendothelioma and retiform hemangioendothelioma (hobnailed hemangioendothelioma), pseudomyogenic hemangioendothelioma, composite hemangioendothelioma, and YAP1::TFE3-fused hemangioendothelioma. The clinical, morphologic, immunohistochemical, and genetic features, and the differential diagnosis of each of these rare entities are discussed in this review.

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.

Untying the Gordian knot of composite hemangioendothelioma: Discovery of novel fusions.

Composite hemangioendothelioma is a rare, locally aggressive, and rarely metastasizing vascular neoplasm which affects both children and adults. Recently, a number of gene fusions including YAP1::MAML2, PTBP1::MAML2, and EPC1::PHC2 have been detected in a small subset of cases with or without neuroendocrine expression. Herein, we present four additional cases with novel in-frame fusions. The cohort comprises two females and two males with a wide age range at diagnosis (24-80 years). Two tumors were deep involving the right brachial plexus and mediastinum, while the remaining were superficial (right plantar foot and abdominal wall). The size ranged from 1.5 to 4.8 cm in greatest dimension. Morphologically, all tumors had an admixture of at least two architectural patterns including retiform hemangioendothelioma, hemangioma, epithelioid hemangioendothelioma, or angiosarcoma. The tumors were positive for endothelial markers CD31 (3/3), ERG (4/4), and D2-40 (1/4, focal), while SMA was expressed in 2/3 highlighting the surrounding pericytes. Synaptophysin showed immunoreactivity in 2/3 cases. One patient had a local recurrence after 40 months, while two patients had no evidence of disease 4 months post-resection. Targeted RNA sequencing detected novel in-frame fusions in each of the cases: HSPG2::FGFR1, YAP1::FOXR1, ACTB::MAML2, and ARID1B::MAML2. The two cases with neuroendocrine expression occurred as superficial lesions and harbored YAP1::FOXR1 and ARID1B::MAML2 fusions. Our study expands on the molecular spectrum of this enigmatic tumor, further enhancing our current understanding of the disease.

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.

Rare adult Kaposiform hemangioendothelioma with multiple-bone invasion - clinical experience and literature review.

BACKGROUND: Kaposiform hemangioendothelioma (KHE) is a borderline vascular tumor between hemangioma and malignant angiosarcoma. While KHE has strong local invasion with rare spontaneous regression, it is not observed with distant metastasis. Even if KHE is asymptomatic or without the Kasabach-Merritt phenomenon (KMP), bone or joint invasion should clearly receive proactive treatment. KHE commonly affects infants/children but is rarely seen in adults. CASE REPORT: We reported a rare adult KHE case with an invasion of >10 separate forearm/hand bones, who underwent multiple-lesion resection and finger amputation after tumor recurrence. Tumor recurrence and KMP were not observed during the 6-month follow-up after the final operation. During the hospitalization and follow-up period, the patient only received medications for infection prevention and pain relief. CONCLUSIONS: Multiple resectable lesions were found in the distal limb, for which complete resection might not present typical features (high-intensity T2-weighted MRI), which might fail to detect all KHE lesions. Therefore, complete excision is not optimal for multiple resectable KHE lesions.

Kaposiform hemangioendothelioma of the heart: a case report and literature review.

Kaposiform hemangioendothelioma is a rare tumour of vascular origin that rarely occurs in the heart. We provided a rare case of a 26-day-old infant with tachypnoea. Echocardiography showed a solid tumour in the pericardial cavity and a large amount of pericardial effusion. The solid tumour was confirmed by surgery, and the pathology was kaposiform hemangioendothelioma. We analysed this case and reviewed the related literature to explore the clinical features and echocardiographic manifestations to improve the understanding, diagnosis, and treatment of this disease for clinicians and sonographers.

Incidence, demographics, and survival of malignant hemangioendothelioma in the United States.

BACKGROUND: Malignant hemangioendothelioma is an endothelial cancer with heterogeneous clinical behavior that can range from indolent to aggressive, of which the majority are epithelioid (EHE). Its incidence and demographics have not been previously well defined in a large cohort. METHODS: This retrospective analysis used the US Cancer Statistics National Program of Cancer Registries - Surveillance Epidemiology End Results (SEER) combined database to identify patients in the US newly diagnosed with hemangioendothelioma between the years of 2001 and 2017 (n = 1986). Survival analyses were performed on a subset of patients within the SEER-18 database with survival information available (n = 417). Outcomes included incidence, demographics of patients newly diagnosed with hemangioendothelioma, extent of disease at presentation, and overall survival. RESULTS: The incidence of hemangioendothelioma in the US is 0.4 cases per million person-years. Although cases rose to 122 newly diagnosed in the year 2017 (90 EHE, 32 other hemangioendothelioma), incidence rates were stable. Skin and connective tissues were the most common presenting sites (33.4%), followed by liver (24.5%), lung (17.6%), and bone (12.5%). Median age at diagnosis was 55 years; 27.2% of patients were pediatric, adolescent, or young adult (<40 years). At presentation, 36.4% of patients had localized disease; 21.6% presented with regional and 41.7% with distant metastases. Observed survival at 3 years was 79.7%, 70.7%, and 46.0% for patients presenting with local, regional, and distant disease and most deaths occurred within the first 2 years. CONCLUSIONS: Malignant hemangioendothelioma is ultra-rare but meaningfully impacts affected patients. These data may provide benchmarks for comparison of new approaches to hemangioendothelioma therapy and highlight poor survival outcomes.

Benign and low-grade superficial endothelial cell neoplasms in the molecular era.

Vascular tumors are the most common mesenchymal neoplasms of the skin and subcutis, and they encompass a heterogeneous group with diverse clinical, histological, and molecular features, as well as biological behavior. Over the past two decades, molecular studies have enabled the identification of pathogenic recurrent genetic alterations that can be used as additional data points to support the correct classification of these lesions. The purpose of this review is to summarize the available data related to superficially located benign and low-grade vascular neoplasms and to highlight recent molecular advances with the role of surrogate immunohistochemistry to target pathogenic proteins as diagnostic biomarkers.

Clinicopathological study of pseudomyogenic hemangioendothelioma.

OBJECTIVES: Pseudomyogenic hemangioendothelioma (PHE) is a rare intermediate hemangioendothelioma. This article aims to study the clinicopathological features of PHE. METHODS: We collected the clinicopathological features of 10 new PHE, and examined their molecular pathological features by fluorescence in situ hybridization. In addition, we summarized and analyzed the pathological data of 189 reported cases. RESULTS: The case group consisted of six men and four women aged 12-83 years (median: 41 years). Five instances occurred in the limbs, three in the head and neck, and two in the trunk. Tumor tissues were composed of spindle cells and round or polygonal epithelioid cells, which were either arranged in sheets or interwoven, along with areas of transitional morphology. Scattered or patchy stromal neutrophil infiltration was observed. Tumor cells had abundant cytoplasm, and some contained vacuoles. The nuclei had mild to moderate atypia, with visible nucleoli, and mitosis was rare. PHE tissues diffusely expressed CD31 and ERG, but not CD34, Desmin, SOX-10, HHV8 or S100, while some samples expressed CKpan, FLI-1 and EMA. INI-1 stain is retained. The proliferation index of Ki-67 is 10-35%. Seven samples were detected by fluorescence in situ hybridization, six of which had breakages in FosB proto-oncogene (AP-1 transcription factor subunit). Two patients experienced recurrence; however, no metastasis or death occurred. CONCLUSIONS: PHE is a rare soft tissue vascular tumor, which has biologically borderline malignant potential, local recurrence, little metastasis, and good overall survival and prognosis. Immunomarkers and molecular detection are valuable for diagnosis.

Epithelioid Hemangioendothelioma in the Tongue: A Rare Case Report.

Epithelioid hemangioendothelioma is a rare malignant vascular neoplasm caused by the proliferation of neoplastic endothelial cells. Epithelioid hemangioendothelioma may develop in any organ, but it is commonly observed in the extremities. The tongue is a very unusual location for epithelioid hemangioendothelioma. A 55-year-old male patient presented to the outpatient head and neck clinic with lumps in the tongue, pain, and limitation of motion. The polypoid mass detected in the anterior midline of the tongue was excised. Microscopically, the tumor cells included slightly pleomorphic oval or round vesicular nuclei with an eosinophilic cytoplasm that variably contained vacuoles. There were 4 mitoses per 10 high power fields and there was no necrosis. In immunohistochemical study, the tumor cells were positively stained with CD31 and CD34 whereas they were negatively stained with TFE3, SMA, S-100, HHV-8 and EMA. The patient was diagnosed with "epitheloid hemangioendothelioma". Only ten cases have been reported in the tongue in the literature. Our case was the eleventh case, and we aimed to report this case as a rare entity with an unusual location.

Spontaneously regressive multifocal bone pseudomyogenic hemangioendothelioma in a 17-year-old boy: a case report.

Pseudomyogenic hemangioendothelioma (PMH) is a rare vascular tumor that occurs in young mostly male patients. Seventy percent of PMH cases are multifocal and 25% involve bones. PMH is an indolent tumor with mild local aggressiveness and an unclear pathology. Only two cases of spontaneous regressive bone PMH have been reported. Here, we report the case of a 17-year-old boy with a multifocal bone PMH diagnosed from a chronic pain in his left knee. The PMH affected the right scapula, both humeri, the right olecranon, the second metacarpal bone, the second and fourth right ribs, the thoracic and lumbar spine, the pelvic ring, the left and right femoral neck, and the left patella. Every lesion presented with a lobulated, lytic pattern, sometimes with a peripheral sclerotic rim. MRI showed a tissue lesion with a low intensity on T1-weighted sequences and high intensity on T2-weighted sequences. Enhancement of T1 gadolinium fat-saturated sequences was bright. After discussion, a national specialized board decided to actively monitor the patient and start general chemotherapy in the case of progression. The disease was stable at 3 and 6 months and showed signs of regression at 1 year, which was further confirmed at 2 years. CT scan and MRI highlighted a progressive filling of the tumor with cancellous bone and a regression of the tissue contingent. This case report highlights to a new therapeutic approach for indolent PMH that does not prevent further treatment in the case of progression.

Multiple papillary intralymphatic angioendotheliomas in the spleen.

A 18-year-old man presented with multiple asymptomatic masses in the spleen that had been detected on ultrasonography performed during a physical screening. He had no history of tuberculosis, and was otherwise well. Abdominal MR demonstrated multiple masses with internal stellate scars, which appeared as marked hypointensity on T2WI and contrast-enhanced MR. Most lesions showed inhomogeneous enhancement. The capsular enhancement was also revealed at delay phase. The patient underwent laparoscopic splenectomy. Pathological examination indicated papillary intralymphatic angioendothelioma (PILA), with the following immunohistochemistry results: CK (-), CR (-), ERG (+), CD34 (+), CD31 (+), D2-40 (+), Ki67 (3%+). The patient was feeling well at 6 months of follow-up.

Sacrococcygeal mass in a 3-year-old unfolding as Dabska tumor-A very rare entity.

ABSTRACT: Papillary intralymphatic angioendothelioma, previously known as Dabska's tumor, is a very rare entity in children involving the skin and soft tissue. It is a low grade tumor characterized by papillary endovascular proliferations of atypical endothelial cells and anastomosing vascular channels in the dermis. We present a 3-year-old male child, with a history of swelling and mild pain in the right upper gluteal region, progressive in nature for 1 month duration. On examination, the swelling was soft to firm and mildly tender. Radiology was suggestive of Sacro-coccygeal teratoma. Grossly, it was an ill-defined grey brown lesion measuring 3.5 × 3 × 2 cm. Microscopy showed lesion arranged in papillary pattern with slit like vascular channels and intra luminal proliferations of hobnail like endothelial cells. Morphology and immunohistochemical studies revealed a diagnosis of Papillary intralymphatic angioendothelioma.