Pathology of Kaposiform Hemangioendothelioma
hemangioendothelioma is a locally aggressive, non-metastasizing vascular tumour.
This lesion is commonly associated with Kasabach-Merritt syndrome and lymphangiomatosis.
Site: Retroperitoneum, subcutaneous or deep soft tissue of upper extremities, head and neck area.
Age: Occurs as solitary tumour in infants (first decade of life) .
Tumour consists of infiltrating lobulated nodules of spindle shaped endothelial cells
Nodules are separated by thick fibrous bands ;
Spindle cells form short fascicles and line slit-like and round vessels ;
Minimal cytological atypia ;
Mitotic activity is low ;
Epithelioid cells are sometimes present ;
Cells may contain hemosiderin pigment, hyaline globules and cytoplasmic vacuoles;
Ectatic vessels are present in the periphery ;
Scattered microthrombi may be present within vascular spaces.
The spindle cells stain positively for CD34 and focally for CD31.
The pericytes around the capillaries stain positively for smooth muscle actin.
Vascular Endothelial Growth Factor Receptor-3 (VEGFR-3): A Marker of Vascular Tumors with Presumed Lymphatic Differentiation, Including Kaposi's Sarcoma, Kaposiform and Dabska-Type Hemangioendotheliomas, and a Subset of Angiosarcomas.
Differential diagnosis :
Kaposi's sarcoma (rare in children; multicentric; prominent chronic inflammatory infiltrate; lobular architecture is absent; dense fibrous bands are not present); infantile hemangioma ; acquired tufted hemangioma ; spindle cell hemangioendothelioma ;
(endothelial atypia, increased mitotic activity and dermal collagen
dissection by infiltrating tumour)
Kaposiform hemangioendothelioma complicated by kasabach-merritt phenomenon: ultrastructural observation and immunohistochemistry staining reveal the trapping of blood components
Kaposi-like infantile hemangioendothelioma. A distinctive vascular neoplasm of the retroperitoneum.
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