Kasposiform hemoangioendothelioma (KHE) and tufted angioma (TA) are classifed as vascular tumors with locally aggressive and benign growth potential, respectively, within the classification schema proposed by the International Society for the Study of Vascular Anomalies. A unique feature of these vascular tumors is the risk of Kasabach-Merritt phenomenon (KMP), a severe thrombocytopenia with mild to moderate coagulopathy resulting from intralesional platelet trapping. As with many vascular anomalies, accurate description of clinical course, responses to therapy, and long-term outcomes have been hindered by lesion misidentification, imprecise nomenclature, and lack of prospective, randomized clinical trials to assess therapeutic efficacy. The classic dermatologic features of these lesions can facilitate diagnosis for the astute provider; however, the absence of or unusual integumentary involvement or presentation in a less common age group (adolescents/adults) poses a diagnostic challenge. Current approaches to the management of KHE/TA are often informed by lesion features such as presence of KMP, extent and location of the tumor, and symptomatology. Evidence-based treatment guidelines are limited. Corticosteroids, vincristine, interferon, multi-agent regimens and newer therapies, such as sirolimus, have demonstrated efficacy in patient series. The use of surgical excision and interventional radiology guided therapies have been described with mixed clinical benefit. Collaboration among emerging vascular anomaly centers and an increasing number of providers across subspecialties with interest in this field are facilitating the development of standardized approaches to diagnosis and management. The rarity of KHE-spectrum lesions and the heterogeneity of clinical manifestations necessitate rationally designed, multisite clinical trials to investigate risk stratification schemas and formally evaluate the short and long-term efficacy of available and novel therapies.

Kaposiform hemangioendothelioma (KHE) is a rare, potentially life-threatening vascular tumor first depicted in a case report in 1940 as a “capillary hemangioma” with purpura and severe thrombocytopenia known as Kasabach-Merritt phenomenon (KMP).