Kasabach Merritt Syndrome

Patients with Kasabach Merritt syndrome may present for the evaluation of cutaneous lesions [1], for symptoms caused by visceral vascular tumors or for milder dermal manifestations of the disease [2], like petechiae, bruising [3] or bleeding. With hepatic angiomas, patients can have hepatomegaly and jaundice. If the vascular tumor is large, a great amount of blood circulates within it, causing symptomatic high output heart failure [4]. Large lesions may also cause compression of the neighboring structures, with various signs, depending on their location. Death can be due to cerebral bleeding from an intracranial pathology [5], or secondary to disseminated intravascular coagulation, multiorgan failure, shock, and sepsis. Hemangiomas may be located anywhere: the skin, retroperitoneal organs, mediastinum, pelvis, neck, limbs, musculoskeletal, visceral organs. Symptoms may become worse as the child grows older and subsequently, the vascular tumor grows larger. However, patients may remain asymptomatic until they become adults or may present during the first weeks of life.

When no cutaneous lesions are present, the diagnosis is easily missed unless a thorough examination that suggests liver or spleen enlargement, for instance, is performed [6]. Still, clinical examination may be uninformative in some patients, like those with intraosseous disease [7] [8], therefore the diagnosis relies on a high level of suspicion, laboratory and imaging data.

Clinical examination may reveal pallor, reddish-brown, indurated lesions [9], classical capillary hemangiomas or tufted angiomas. Patients may be tachycardic due to the anemia, heart failure or shock. Lesion ulceration and infection are rarely seen.

In Kasabach Merritt syndrome, blood workup should include complete blood count, peripheral smear, fibrinogen, fibrin degradation products, D-dimers, prothrombin time and activated partial thromboplastin time. The laboratory personnel should look for Burr cells and schistocytes. Disseminated intravascular coagulation is accompanied by prolonged prothrombin time and activated partial thromboplastin time, low fibrinogen level, elevated fibrin degradation product and D-dimer levels. Intravascular coagulation may also have a chronic, low-grade character.

It is important to determine the extent of cutaneous lesions and the existence of other involved sites, therefore radiography, ultrasonography- especially Doppler flow, computed tomography, Indium or Chromium radionuclide scintigraphy [10] magnetic resonance imaging scans and angiographic scans should be performed. Angiography can be followed by embolization. When the nature of the tumor is uncertain, histologic findings are important to evaluate its nature [11], but biopsies are usually not performed due to the critical state of the patient unless surgical procedures are performed with curative intent. Most frequently, kaposiform haemangioendothelioma and tufted angiomas are found [12]. Both contain dilated capillary vessels with endothelial lesions, microthrombi, lymphlike vessels and hemosiderin deposits, and both may be found in the same patient.

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