Sirolimus combined with glucocorticoids in the treatment of Kasabach-Merritt phenomenon in a neonate: A case report.

RATIONALE: Kaposiform hemangioendothelioma is an aggressive vascular tumor that is often associated with life-threatening coagulopathies and Kasabach-Merritt phenomenon. Pathologic biopsies can provide a good basis for diagnosis and treatment. Therapy with srolimus combined with glucocorticoids may offer patients a favorable prognosis. PATIENT CONCERNS: A large purplish-red mass on the knee of a child with extremely progressive thrombocytopenia and refractory coagulation abnormalities. Conventional doses of glucocorticoids alone failed to improve coagulation abnormalities and the child developed large cutaneous petechiae and scalp hematomas. DIAGNOSIS: Kaposiform hemangioendothelioma combined with Kasabach-Merritt phenomenon. INTERVENTIONS: The patient received prednisolone 2.0 mg/kg*d for 4 days. Blood products were transfused to ensure vital signs and to complete the pathologic biopsy. Sirolimus combined with prednisolone was given after clarifying the diagnosis of Kaposiform hemangioendothelioma. OUTCOMES: The tumor basically disappeared on examination and the ultrasound showed a subcutaneous hyperechoic mass with normal blood flow. LESSONS: Sirolimus combined with glucocorticoids is effective in controlling Kasabach-Merritt phenomenon and pathologic biopsy is important for definitive diagnosis.

How we use angiopoietin-2 in the diagnosis and management of vascular anomalies.

The diagnosis of vascular anomalies remains challenging due to significant clinical heterogeneity and uncertain etiology. Evaluation using biopsy and/or genetic testing for somatic variants is invasive, expensive, and prone to sampling error. There is great need for noninvasive and easily measured blood laboratory biomarkers that can aid not only in diagnosis, but also management of treatments for vascular anomalies. Angiopoietin-2, a circulating blood angiogenic factor, is highly elevated in patients with kaposiform hemangioendothelioma with Kasabach-Merritt phenomenon and kaposiform lymphangiomatosis. Here, we describe our clinical experience using serum angiopoietin-2 as a biomarker for diagnosis and monitoring response to treatment.

Cost and effectiveness comparison of sirolimus versus standard treatment in Kasabach-Merritt phenomenon: a real-world evidence study in Thailand.

The conventional treatment of Kasabach-Merritt Phenomenon (KMP) consists of corticosteroids with vincristine/vinblastine or others. The aim of the study is to compare the first-year direct costs and effectiveness between sirolimus and conventional treatment. A retrospective case-control study of KMP patients was conducted at a mean age of 9 months (1 day to 12 years) between 2000 and 2022 from four tertiary centers in Thailand. The direct costs, hematologic and clinical complete response (HCR, CCR), hospitalization, length of stay, and complications were compared. Of 29 patients, 13 underwent sirolimus (four upfront and nine were refractory to the conventional). The first-year total cost had no statistically significant difference between sirolimus VS conventional treatment (8,852.63 VS 9,083.56 USD: p value: 0.94). The therapeutics achievement was the same in both HCR (244.75 VS 168.94 days; p value: 0.60) and CCR (419.77 VS 399.87 days; p value: 0.90). The subgroup analysis of the first-line sirolimus (n = 4) compared with the conventional (n = 25) showed a more reduced total cost (4,907.84 VS 9,664.05 USD; p value: 0.26) rendered net total cost of -4,756.21 USD per patient (cost saving). A more significant contrast of therapeutic achievement by reduction of both HCR (11.67 VS 224.20 days; p value: 0.36) and CCR (38.50 VS 470.88 days; p value: 0.04) was shown. The sirolimus had no difference in hospitalization, length of stay, and complications. Even though, it was unable to identify significant differences in cost-effectiveness. Sirolimus is suitable for all patients who have diagnosis of KMP either for rescue therapy or first-line treatment.

Kaposiform Hemangioendothelioma with Bone Destruction: A 16-Year Follow-Up Cohort Study of the Clinical Characteristics and Prognosis.

BACKGROUND: Kaposiform hemangioendothelioma (KHE) is a rare, locally aggressive vascular tumor that often occurs in infants and young children. The goal of this study was to analyze the clinical characteristics of KHE patients with bone destruction and provide clinical guidance for diagnosis and treatment. METHODS: We conducted a descriptive cohort study with follow-up from January 2007 to January 2023 to collect demographic information and tumor-related clinical information from KHE patients with bone destruction. RESULTS: A total of 269 KHE patients were included in the study, of whom 70 (26.0%) patients had tumors with bone destruction. The median age at diagnosis of patients with bone destruction was 19.0 months, which was much later than that of patients without bone destruction (P < 0.001). Patients with bone destruction were more likely to have a decreased range of motion (ROM) (P < 0.001). Metaphysis involvement was more likely to occur in the lower limb bones (P = 0.039), and the lower limb bones were more likely to be associated with decreased ROM (P = 0.001). Tumors involving extracompartmental bone were more likely to have decreased ROM (P = 0.003) and exhibit the Kasabach-Merritt phenomenon (P = 0.006). CONCLUSIONS: Based on the rarity and significant heterogeneity of KHE patients with bone destruction, we should give full play to the role of multidisciplinary teams in addressing disease to reduce the long-term complications of KHE with bone destruction and improve the quality of life of patients. TYPE OF STUDY: Prognostic Study. LEVEL OF EVIDENCE: Level II.

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.

Locally Invasive Papillary Intralymphatic Angioendothelioma Arising Within a Lymphatic/Venous Malformation.

BACKGROUND Papillary intralymphatic angioendothelioma (PILA) is a rare vascular tumor affecting children and young adults, with less than 50 cases reported in the literature. This tumor typically presents in the extremities, exhibits borderline behavior, and has a prominent lymphatic phenotype. Originally thought to be malignant, PILA was later recognized for its borderline behavior and lymphatic features, leading to its current classification as a "rarely metastasizing lymphatic vascular neoplasm". CASE REPORT We present the case of a 10-year-old girl with a 6-year history of a right facial venous malformation, which was ultimately diagnosed as PILA in the background of lymphatic/venous malformation (LVM). After undergoing surgical excision of a right facial soft-tissue tumor, histopathological examination revealed scattered lymphatics and thin-walled vascular channels with blood in skeletal muscle and fibroadipose tissue. Intraluminal papillary proliferation of vascular spaces lined by cytologically bland spindle cells was observed, along with Kaposiform morphology and small-vessel proliferation. Immunohistochemical staining confirmed endothelial cell markers (D2-40, ERG, CD34, and CD31) and numerous CD3(+) lymphocytes in the lumen, surrounded by CD3(+) T lymphocytes and CD20(+) B lymphocytes in the surrounding stroma. The tumor lacked pleomorphism, significant mitotic activity, and necrosis. CONCLUSIONS PILA presents a diagnostic challenge and should be considered in the differential diagnosis of cutaneous vascular neoplasms. Long-term follow-up is crucial due to its borderline behavior and potential for local invasiveness and metastasis. Accurate diagnosis, aided by characteristic histological and immunohistochemical features, is essential for appropriate management of this rare vascular tumor.

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.

Recurrent metastatic angiosarcoma presenting as Kasabach-Merritt syndrome.

Angiosarcoma is an incredibly rare type of malignancy, accounting for only 1%-2% of all soft-tissue sarcomas globally. It is clinically, pathologically and radiologically difficult to diagnose angiosarcoma owing to its varied presentation with little or no well-defined imaging findings.Kasabach-Merritt syndrome is also a lesser-heard entity which carries extremely poor prognosis. It is primarily seen in infants with vascular malformations and in kaposiform haemangioendothelioma. It is a condition of consumptive coagulopathy and only few of the cases have been reported so far in the adults with a background of angiosarcoma.This report presents the case of a male in his 70s who was diagnosed with metastatic angiosarcoma and experienced a complicated disease course due to Kasabach-Merritt syndrome.

Platelet functional abnormalities in pediatric patients with kaposiform hemangioendothelioma/Kasabach-Merritt phenomenon.

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor of infancy that is commonly associated with a life-threatening thrombocytopenic condition, Kasabach-Merritt phenomenon (KMP). Platelet CLEC-2, tumor podoplanin interaction is considered the key mechanism of platelet clearance in these patients. Here, we aimed to assess platelet functionality in such patients. Three groups of 6 to 9 children were enrolled: group A with KHE/KMP without hematologic response (HR) to therapy; group B with KHE/KMP with HR; and group C with healthy children. Platelet functionality was assessed by continuous and end point flow cytometry, low-angle light scattering analysis (LaSca), fluorescent microscopy of blood smears, and ex vivo thrombi formation. Platelet integrin activation in response to a combination of CRP (GPVI agonist) and TRAP-6 (PAR1 agonist), as well as calcium mobilization and integrin activation in response to CRP or rhodocytin (CLEC-2 agonist) alone, were significantly diminished in groups A and B. At the same time, platelet responses to ADP with or without TRAP-6 were unaltered. Thrombi formation from collagen in parallel plate flow chambers was also noticeably decreased in groups A and B. In silico analysis of these results predicted diminished amounts of CLEC-2 on the platelet surface of patients, which was further confirmed by immunofluorescence microscopy and flow cytometry. In addition, we also noted a decrease in GPVI levels on platelets from group A. In KHE/KMP, platelet responses induced by CLEC-2 or GPVI activation are impaired because of the diminished number of receptors on the platelet surface. This impairment correlates with the severity of the disease and resolves as the patient recovers.

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.

Patient with composite haemangioendothelioma containing angiosarcoma-like areas in the setting of congenital lymphoedema mimicking Stewart-Treves syndrome: a case report.

BACKGROUND: Composite haemangioendothelioma is a rare vascular neoplasm with indolent to intermediate malignant potential. Diagnosis of this disease relays on histopathological identification of at least two different morphologically distinctive vascular components in proper clinical settings. Exceedingly rare cases of this neoplasm can exhibit areas resembling high-grade angiosarcoma, which does not change the biological behaviour. Such lesions tend to occur in the setting of chronic lymphoedema and thus, can mimic Stewart-Treves syndrome, which has a much worse clinical outcome and prognosis. CASE PRESENTATION: We present a case of 49 years old male suffering from chronic lymphoedema of the left lower extremity who had developed a composite haemangioendothelioma with high grade angiosarcoma-like areas mimicking the Stewart-Treves syndrome. Given the multifocality of the disease, the only potentially curable surgical treatment would be hemipelvectomy, which was refused by the patient. The patient has been followed-up, with no signs of local progression of the remaining disease, nor a distant spread outside the involved extremity for two years. CONCLUSIONS: Composite haemangioendothelioma represents a rare malignant vascular tumour, with significantly more favourable biological behaviour than angiosarcoma, even in cases where angiosarcoma-like areas are present. For that reason, composite haemangioendothelioma can be easily misdiagnosed as true angiosarcoma. The rarity of this disease unfortunately hampers the development of clinical practice guidelines and the implementation of treatment recommendations. Most of the patients with localized tumour are treated by wide surgical resection, without neo- or adjuvant radiotherapy or chemotherapy. However, in the case of this diagnosis, the watch-and-wait approach is better than mutilating procedure, highlighting the necessity of establishing of the correct diagnosis.

Efficacy of transcatheter arterial chemoembolization combined with sirolimus for treating Kasabach-Merritt phenomenon in infants, a retrospective study.

OBJECTIVE: This retrospective study aimed to observe the efficacy of transcatheter arterial chemoembolization (TACE) combined with sirolimus in the treatment of haemangioma combined with the Kasabach-Merritt phenomenon (KMP). METHODS: A total of 11 infants with KMP who were treated at our hospital from January 2016 to September 2021 were selected and treated with arteriosclerosis embolotherapy using a microsphere emulsion formed by bleomycin + ultra-fluid lipiodol + dexamethasone + contrast agent or bleomycin mixed microspheres as the embolising agent. The patients were administered sirolimus orally after TACE. The clinical efficacy and examination indicators before and after treatment were observed and compared. RESULTS: The 11 infants underwent TACE treatment by arteriosclerosis embolotherapy a total of 21 times; of these cases, 10 were cured, and 1 showed a moderate response. There were no cases of non-response or death. The platelet count rose from 10.0 (7.0, 18.0) x 109/L before TACE to 236.0 (188.0, 275.0) x 109/L six months after the first TACE, and the tumour size decreased from 49.0 (43.0, 111.7) cm3 before TACE to 7.0 (3.5, 17.0) cm3 six months after the first TACE. The differences were statistically significant (the Z values were -2.943 and -2.934, respectively, p < 0.05). CONCLUSION: The combination of TACE and sirolimus has significant efficacy on critical children with KMP.

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.

Progressive kaposiform hemangioendothelioma and sirolimus-related severe thrombocytopenia.

Kaposiform hemangioendothelioma is a locally invasive tumor and we were unable to find any previous reports of multifocal progression. Sirolimus, a mammalian target of rapamycin inhibitor, has been widely used to treat kaposiform hemangioendothelioma. Herein, we report a case of multifocal progressive kaposiform hemangioendothelioma, wherein sirolimus treatment caused severe thrombocytopenia. A 12-year-old East Asian girl presented with indurated dark-purple masses on her back. The patient had received three surgical interventions following the first appearance of the masses in 2012 and subsequent reappearances in 2014 and 2016. Kaposiform hemangioendothelioma was diagnosed based on radiological and pathological findings. Two more masses appeared in the following year. The patient was treated with oral sirolimus (2.5 mg/ m2/day) and developed grade 3 thrombocytopenia 8 days later. The patient was uneventfully relieved 5 days later after the withdrawal of sirolimus and the administration of appropriate medications. This rare case indicated that kaposiform hemangioendothelioma could be progressive with local metastatic characteristics in children. Besides, the severe sirolimus-induced complication highlights the importance of serum drug level monitoring during treatment. Physicians should be extremely cautious while treating kaposiform hemangioendothelioma patients with sirolimus.

The use of mTOR inhibitors for the treatment of kaposiform hemangioendothelioma. A systematic review.

BACKGROUND: Kaposiform hemangioendothelioma (KHE) is a locally aggressive and potentially lethal vascular tumor of infancy. Current consensus recommendations include the use of vincristine and/or systemic steroids as first-line treatment. Mammalian target of rapamycin (mTOR) inhibitors represent a promising therapy for patients with KHE. The goal of our study is to critically assess the existing literature on outcomes of patients with KHE treated with mTOR inhibitors. METHODS: We conducted a literature search from 1 January 2000, to 30 April 2022. Articles reporting outcomes of patients treated with mTOR inhibitors for KHE were included. Descriptive statistics were used to describe and summarize the outcomes of the treatment. RESULTS: We included 327 patients with a mean age at diagnosis of 9.1 months (SD ± 9). Patients were treated with an mTOR inhibitor for a mean of 15.2 months (SD ± 4.1). A total of 315 (96.3%) patients had positive outcomes including improvement of the tumor size, symptoms and/or laboratory parameters in 227 (85%) and complete remission in 38 (12%). Seven (2%) patients did not respond to treatment and seven (2%) died of sepsis (4), Kasabach-Merritt phenomenon complications (1), cardiac and liver failure due to ductus arteriosus (1), or metastatic disease (1). CONCLUSION: This systematic review supports the efficacy and safety of mTOR inhibitors for KHE. Their use resulted in positive outcomes in terms of decreased symptoms, reduction in tumor size and improvement in biochemical parameters with a mortality rate of 2%. According to these findings, we suggest revised consensus treatment guidelines for KHE with mTOR inhibitors potentially considered first-line therapy.

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 (AU)