Diffuse hemangiomatoses are extremely rare in adults. The etiology and natural history of the disease are not well understood. A case of diffuse hemangiomatosis of the liver and spleen associated with progressive liver failure, thrombocytopenia, and disturbance of blood coagulation (comparable to Kasabach-Merritt syndrome) is presented in a 62-year-old male. We describe the histopathological and immunohistochemical findings and illustrate the morphological aspects of differential diagnosis, distinguishing the disease from other vascular proliferations.