Kaposiform hemangioendothelioma with associated Kasabach-Merritt phenomenon

Hemangioendothelioma

Hemangioendothelioma is the term used to name those vascular neoplasms that show a borderline biological behavior, intermediate between entirely benign hemangiomas and highly malignant angiosarcomas. Although originally spindle cell hemangioendothelioma was proposed as a specific clinicopathologic variant of hemangioendothelioma, currently, it is considered as an entirely benign lesion, and thus, the name spindle cell hemangioma seems to be the most accurate for this lesion. Authentic hemangioendotheliomas involving the skin and soft tissues include papillary intralymphatic angioendothelioma (also known as Dabska tumor), retiform hemangioendothelioma, kaposiform hemangioendothelioma, epithelioid hemangioendothelioma, pseudomyogenic hemangioendothelioma (also known as epithelioid sarcoma-like hemangioendothelioma), and composite hemangioendothelioma. Each of these neoplasms exhibit characteristic histopathologic features. The most characteristic finding of papillary intralymphatic hemangioendothelioma consists of papillary tufts, with a central hyaline core lined by hobnail-like endothelial cells protruding into the lumina. Retiform hemangioendothelioma is an infiltrative neoplasm composed of elongated arborizing vessels, arranged in an anastomosing pattern that resembles that of the rete testis, and lined by a single layer of hobnail-like endothelial cells that protrude within the narrow lumina. Kaposiform hemangioendothelioma is composed of several solid poorly circumscribed nodules, and each nodule is composed of a mixture of small capillaries and solid lobules of endothelial cells arranged in a glomeruloid pattern. A frequent finding consists of the presence of areas of lymphangiomatosis adjacent to the solid nodules. Epithelioid hemangioendothelioma is composed of cords, strands, and solid aggregates of round, oval, and polygonal cells, with abundant pale eosinophilic cytoplasm, vesicular nuclei, and inconspicuous nucleoli, embedded in a fibromyxoid or sclerotic stroma. Many neoplastic cells exhibit prominent cytoplasmic vacuolization as an expression of primitive vascular differentiation. Pseudomyogenic hemangioendothelioma is a poorly circumscribed, fascicular lesion with infiltrative borders composed of round or oval neoplastic cells, with vesicular nuclei and inconspicuous nucleoli, and ample homogeneous eosinophilic cytoplasm, giving them a rhabdomyoblastic appearance. Finally, composite hemangioendothelioma is the term used to name locally aggressive vascular neoplasms of low-grade malignancy showing varying combinations of benign, low-grade malignant, and high-grade malignant vascular components. From the immunohistochemical point of view, proliferating cells of all hemangioendotheliomas express a lymphatic endothelial cell immunophenotype. Most hemangioendotheliomas are low-grade vascular neoplasms, with a tendency to recur locally and a low metastatic potential, mostly to regional lymph nodes. Epithelioid hemangioendothelioma, especially large lesions and those located in deep soft tissues, seems to have a more aggressive biological behavior.

Refractory kaposiform hemangioendothelioma that expressed vascular endothelial growth factor receptor (VEGFR)-2 and VEGFR-3: a case report

This report describes the case of a 10-month-old boy who was diagnosed to have kaposiform hemangioendothelioma (KHE) with Kasabach-Merritt syndrome (KMS), which is a rare pediatric vascular tumor with a high mortality rate. Although both KHE with KMS were resistant to various therapies, such as oral prednisolone, sclerotherapy, and chemotherapy, repeated radiation therapy with methylprednisolone pulse therapy did reduce the volume of KHE and improved the symptoms of KMS. Unfortunately, a regrowth of KHE with KMS was observed 4 months after the cessation of treatment and the patient thereafter died from an intracranial hemorrhage and Pneumocystis carinii pneumonia, which is a complication related to repetitive radiation and steroid therapy. A histopathologic examination of autopsy specimens confirmed a diagnosis of KHE and immunohistologic staining was positive for vascular endothelial growth factor receptor (VEGFR)-2 and VEGFR-3. These findings may provide the rationale to further investigate the role of VEGFRs in the pathogenesis of KHE and also to elucidate its prognostic value, along with the application of inhibitors for VEGFRs for the treatment of refractory KHE.

Kaposiform hemangioendothelioma: a rare cause of spontaneous hemothorax in infancy. Review of the literature

Kaposiform hemangioendothelioma is a rare vascular tumor found almost exclusively in early childhood often associated with a life-threatening thrombocytopenia and consumptive coagulopathy known as Kasabach-Merritt phenomenon. The natural history of these lesions and treatment remains controversial. We portray a case of a spontaneous hemothorax in a 2-month-old female infant and review of 153 reported cases in attempts to better delineate the available treatment options.

Hemangioendotelioma kaposiforme torácico. Cuatro casos con evolución variable

INTRODUCTION

Kaposiform hemangioendothelioma (KHE) is a rare, frequently congenital, neoplasm associated with the Kasabach-Merritt phenomenon (KMP) and predilection for the trunk. Its clinical course is unpredictable. A child with KHE can die as a result of hemorrhage or show early spontaneous regression. In addition various and concurrent therapies can be used to treat this tumor and it is difficult to predict which treatment will be successful.

MATERIAL, METHODS AND RESULTS

We present four consecutive cases of KHE (larger than 20 cm) of the thorax. All patients developed KMP, without skin involvement in one patient. Patient 1, a neonate with KHE occupying both hemithoraces (nearly 50% of the body surface area), died shortly after birth due to coagulopathy and generalized bleeding. Patient 2, a neonate, was treated with interferon alpha-2a and showed accelerated correction of coagulopathy and complete tumoral regression at 9 months. Patient 3 showed no response to steroids, interferon or vincristine therapy. Thrombocytopenia (platelet count 40,000) persisted for 8 years and was resolved by administration of aspirin plus ticlopidine, without tumoral disappearance. Patient 4 underwent incomplete removal of the tumor on her right chest wall after showing no response to antiangiogenic therapy. The coagulopathy persisted and a second radical surgical procedure resolved KMP.

CONCLUSION

Given the variable response to pharmacological treatment and the scant possibilities of surgical resection, the management of KHE with KMP must include a multidisciplinary approach. As little is known about the pathogenesis of these highly aggressive vascular tumors, further molecular research is needed to understand their long-term behavior.

Successful surgical excision of a complex vascular lesion in an infant with Kasabach-Merritt syndrome

Kasabach-Merritt syndrome, the association of a vascular lesion and consumptive coagulopathy, can represent a diagnostic and therapeutic challenge to clinicians. We describe an infant with a large complex vascular lesion of the left forearm that was successfully surgically excised. We propose surgical excision as an appropriate therapeutic option for some cases of Kasabach-Merritt syndrome.