Kaposiform hemangioendothelioma

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor that typically presents in infancy or early childhood. It is classified as a locally aggressive neoplasm of intermediate malignancy, meaning it can invade surrounding tissues but rarely metastasizes to distant sites. KHE most commonly affects the skin, deep soft tissues, and retroperitoneum, and may also involve bone. The tumors appear as firm, reddish-purple, ill-defined masses that can grow rapidly and cause significant morbidity. A hallmark and life-threatening complication of KHE is Kasabach-Merritt phenomenon (KMP), which occurs in a significant proportion of patients. KMP is characterized by profound thrombocytopenia (very low platelet counts), consumptive coagulopathy, and hypofibrinogenemia caused by platelet trapping within the tumor. This can lead to severe, potentially fatal bleeding. Other symptoms include pain, swelling, and functional impairment depending on the tumor's location. Lymphangiomatosis may coexist with KHE in some cases. Treatment of KHE depends on the size, location, and presence of KMP. Sirolimus (an mTOR inhibitor) has emerged as a first-line medical therapy and has shown significant efficacy in reducing tumor size and managing KMP. Other treatments include vincristine, corticosteroids, and antiplatelet agents such as aspirin and ticlopidine. Surgical resection may be considered for localized tumors that are amenable to complete excision, though many KHE tumors are too infiltrative for surgery alone. Supportive care including platelet transfusions and management of coagulopathy is critical in acute settings. Long-term outcomes vary; some tumors may partially regress over time, but residual disease, musculoskeletal complications, and chronic pain can persist.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Kaposiform hemangioendothelioma