UNASSIGNED: Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor with a high risk of mortality. Few studies with large samples of KHE have been reported. KHE may develop into the Kasabach-Merritt phenomenon (KMP), which is characterized by thrombocytopenia and consumptive coagulopathy. The features of severe symptomatic anemia and life-threatening low platelets make the management of KHE associated with KMP challenging.
UNASSIGNED: The aim of this study was to examine the clinical characteristics of patients with KHE and discuss the treatment experience for different risk groups of KHE.
UNASSIGNED: Through a retrospective review of 70 patients diagnosed with KHE between 2017 and 2022 in our center, we classify lesions into three clinicopathological stages based on the tumor involving depth, and divided the severity of KHE into three levels by estimating clinicopathological stages and severity of thrombocytopenia. Treatments of different severity groups were estimated with sufficient data.
UNASSIGNED: In our cohort, 27% were neonates, and KHE lesion occurred at birth in 84% of patients. There was a slight male predominance (32 girls and 38 boys). Common clinical characteristics included associated coagulation disorder (100%), locally aggressive cutaneous blue-purple mass (89%), thrombocytopenia (78%), and local pain or joint dysfunction (20%). The lower extremities were the dominant location (35%), followed by the trunk (29%), the maxillofacial region and neck (24%), and the upper extremities (10%). Of the total cohort, 78% developed KMP; the median age at which thrombocytopenia occurred was 27.8 days. The median platelet count of patients who were associated with KMP was 24,000/µL in our cohort. Ninety-two percent of patients were given surgery treatment and 89% of these patients were given high-dose methylprednisolone (5-6 mg/kg daily) before surgery. In 55 patients with KMP, 36% were sensitive to high-dose corticosteroid therapy. Patients from the low-risk group (eight cases) underwent operation, all of whom recovered without recurrence after a maximum follow-up of 5 years. Out of 26 patients from the high-risk group, 25 underwent surgery treatment, with 1 case undergoing secondary surgery after recurrence and 1 case taking sirolimus. Out of 36 cases from the extremely high-risk group, 32 underwent surgery (including 2 cases who underwent external carotid artery ligation and catheterization), 3 of whom underwent secondary operation after recurrence, and the remaining 4 cases took medicine. The mean length of having sirolimus was 21 months; two cases stopped taking sirolimus due to severe pneumonia. Two cases died at 1 and 3 months after discharge.
UNASSIGNED: Our study describes the largest assessment of high-risk patients with KHE who have undergone an operation to date, with 5 years of follow-up to track recovery, which provides invaluable knowledge for the future treatment of patients with KHE and KMP from different risk groups: Early surgical intervention may be the most definitive treatment option for most patients with KHE; multimodality treatment is the best choice for the extremely high-risk group.

An infant with Kasabach-Merritt Phenomenon (KMP) presented with a giant subcutaneous mass in the right lower limb, severe hypofibrinogenemia, and thrombocytopenia. Glucocorticoids, along with supportive treatments including transfusion of blood products and clotting factors, were administered to reverse fatal disseminated intravascular coagulation and acute hemolysis. The glucocorticoid dose was tapered slowly, and sirolimus was added to treat the hemangiomas. The patient subsequently underwent interventional therapy. After 6 months of medical and interventional therapy, the patient was doing well with a normal platelet count, the tumor volume was markedly reduced, and the primary cutaneous lesion became pale pink. Currently, the patient remains on sirolimus, and no recurrence of thrombocytopenia or further growth of the mass was observed after six months of follow-up.

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.

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BACKGROUND: This study aimed to analyze the angiographic characteristics of kaposiform hemangioendothelioma (KHE) and investigate the value of transcatheter arterial embolization (TAE) therapy.
METHODS: The clinical data of infants diagnosed with KHE at the department from June 2013 to June 2020 were retrospectively analyzed. Of these, 34 infants received TAE therapy. The efficacy of the treatment was evaluated 4 weeks after the therapy. The angiographic characteristics were analyzed by comparing them with the angiographic characteristics of infantile hemangioma (IH), and the times of TAE therapy and the platelet level after each TAE therapy in infants with KHE were summarized.
RESULTS: The present study showed that the capillary blush of KHE was irregular with an obscure boundary and nonuniform distribution. Many fine feeding arteries were present. The diameter of the feeding arteries was disproportionate to the volume of the tumor blush. The normal arteries were usually embedded in the tumor blush. The angiography of common IH in infants also showed tumor blush, but it was usually round with a clear boundary and uniform staining, and was distributed on 1 side of the normal arterial trunk. The infants with KHE received TAE therapy for 2 to 5 times/case, with a total of 104.0 times, with an average of 3.1±0.8/case. Among which, the platelets continued to decline for 9 times after TAE therapy and the platelets increased to ≥100×109/L in 7.8±3.2 days for 95 times after TAE therapy, The average relapse time was 30.0±15.9 days.
CONCLUSIONS: The feeding arteries of KHE were numerous and fine and were not easily embolized. The application of TAE may rapidly improve the platelet level, but the long-term effect is poor.

Kasabach-Merritt phenomenon (KMP) is a rare consumptive coagulopathy associated with specific vascular tumors, kaposiform hemangioendothelioma, and tufted angioma. Kasabach-Merritt phenomenon, characterized by profound thrombocytopenia, hypofibrinogenemia, elevated fibrin split products, and rapid tumor growth, can be life-threatening. Severe symptomatic anemia may also be present. With prompt diagnosis and management, KMP can resolve and vascular tumors have been shown to regress. This review highlights the clinical presentation, histopathology, management, and treatment of KMP associated with kaposiform hemangioendothelioma, and less frequently tufted angioma. A classic clinical case is described to illustrate the presentation and our management of a patient with KMP.