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Kaposiform Hemangioendothelioma (KHE) is a rare, locally aggressive vascular tumor of infancy and early childhood.

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Kaposiform hemangioendothelioma (KHE) is a rare vascular neoplasm that is typically diagnosed in infancy or early childhood. KHE has intermediate tumor type with locally aggressive characteristics. The predominant feature of the pathology of KHE is progressive angiogenesis and lymphangiogenesis.

Clinically, KHE has high morbidity rates, primarily due to local invasive features, compressive effects, or the life-threatening consumptive coagulopathy known as the Kasabach–Merritt phenomenon (KMP) (hemangioma thrombocytopenia syndrome).

https://doi.org/10.1186/s13023-020-1320-1

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https://www.youtube.com/watch?v=ZlTTefjh7nE

• It is intermediate between benign hemangiomas and malignant angiosarcomas.
• Often associated with the Kasabach–Merritt Phenomenon (KMP) (consumptive coagulopathy + thrombocytopenia).

Epidemiology

• Onset: Infants and young children (majority <2 years).
• Very rare (incidence <1/million/year).
• Equal sex distribution.

Pathology

• Composed of spindled endothelial cells forming sheets and slit-like vascular channels.
• Infiltrative growth pattern → invades skin, subcutaneous tissue, muscle, retroperitoneum, mediastinum, or visceral organs (liver, bone, mesentery).
• Does not regress spontaneously (unlike infantile hemangioma).
• Can progress to Kasabach–Merritt phenomenon due to platelet trapping.

Clinical Features

• Cutaneous/subcutaneous mass: firm, ill-defined, purplish lesion.
• Painful, enlarging mass that does not involute.