Infantile hemangioendothelioma of the pelvis associated with Kasabach-Merritt syndrome

Spontaneous regression of a vascular tumor of the skull base--infantile hemangioendothelioma?

Extracerebral masses involving the skull base in children and adolescents are rare. We report on a 4-month-old infant who was diagnosed with a large extracerebral mass in the anterior fossa. Subtotal resection to prevent impending blindness was complicated by almost fatal bleeding. Histopathologically, vessel malformation, epitheloid hemangioendothelioma, and angiosarcoma were possible diagnoses. The residual tumor regressed spontaneously and completely within 6 months after surgery. Retrospectively, histologic and radiologic findings and clinical course prompted the diagnosis of an infantile hemangioendothelioma. To our knowledge, this is the first report on an infantile hemangioendothelioma of the skull base.

Successful treatment with cyclophosphamide of life-threatening diffuse hemangiomatosis involving the liver

A female neonate with diffuse hemangiomatosis and hepatic hemangiomas had cardiac insufficiency develop and had failure to thrive. Her disease was unresponsive to prednisone. She received two courses of cyclophosphamide 10 days apart and a final course 2.5 weeks later. Twelve days after the second course of cyclophosphamide, her liver was significantly smaller. She is now 6-years-old, well-developed, and has no signs of hepatomegaly, malnourishment, or heart failure. Cyclophosphamide appears to be a safe, effective, and rapid treatment of life-threatening hemangiomas of infancy.

Thrombocytopenic coagulopathy (Kasabach-Merritt phenomenon) is associated with Kaposiform hemangioendothelioma and not with common infantile hemangioma

Children with a large vascular tumor and associated Kasabach-Merritt coagulopathy respond inconsistently to therapy and have a high mortality rate. For this reason, we undertook a retrospective study of 21 such patients, and focused on clinical, radiographic, and histopathologic features. The male to female ratio was 1:1.6. Tumor was noted at birth in 50 percent of patients; the remainder appeared throughout infancy. The location was cervicofacial (n = 2), shoulder/upper limb (n = 4), trunk including retroperitoneum (n = 11), and lower limb (n = 4). These tumors grew rapidly to large size and were characterized by cutaneous purpura, edema, and an advancing ecchymotic margin. In contrast to common hemangioma, magnetic resonance imaging showed diffuse enhancement with ill-defined margins, cutaneous thickening, stranding of subcutaneous fat, hemosiderin deposits, and small feeding and draining vessels. All tumors were Kaposiform hemangioendothelioma (KHE); none were infantile hemangioma. Light microscopy showed irregular lobules or sheets of poorly formed, small vascular channels infiltrating and entrapping normal tissues. Characteristic features included spindle-shaped endothelial cells, diminished pericytes and mast cells, microthrombi, and hemosiderin deposits. Wide endothelial intercellular gaps and incomplete basement membranes were seen by electron microscopy. Dilated, hyperplastic, lymphaticoid channels were prominent in one tumor. KHE in 14 infants was treated with interferon alpha-2a: 6 had accelerated regression; 2 had stabilization of growth; and 6 evidenced no response. The mortality rate was 24 percent (5 of 21); this included three infants with retroperitoneal KHE. Kasabach-Merritt phenomenon does not occur with common hemangioma. Rather it is associated with the more aggressive KHE and rarely with other vascular neoplasms. Variable response to current pharmacologic therapy underscores our inadequate knowledge of the pathogenesis of thrombocytopenia in KHE.

Infants with Kasabach-Merritt syndrome do not have "true" hemangiomas

OBJECTIVE

In 1940 Kasabach and Merritt described an infant with a vascular anomaly, extensive purpura, and thrombocytopenia; they called his lesion "capillary hemangioma." Hemangioma is a benign tumor that grows in infancy and is characterized by proliferation of endothelial cells and regression during childhood. Although Kasabach-Merritt syndrome (KMS) is frequently mentioned as a possible complication of hemangioma, our experience suggests that the anatomic vascular lesion underlying the thrombocytopenia is not a "true," classic, involuting type of hemangioma of infancy and childhood.

STUDY DESIGN

We reviewed the clinical and hemostasis data and the response to treatment in 22 cases of KMS, and we analyzed the biopsy specimens of 15 of them.

RESULTS

Clinically none of the 22 patients had classic hemangioma. There was no female preponderance. All patients had severe thrombocytopenia (lowest platelet count = 3000/mm3) and consumption of fibrinogen. Histologically, none had the typical "capillary," involuting type of hemangioma of infancy: they exhibited either a tufted angioma or a kaposiform hemangioendothelioma pattern; all specimens also contained numerous abnormal lymphatic-like vessels; lymphatic malformation was the major component in two patients. The infants exhibited a heterogeneous response to a number of therapeutic regimens, as noted in other reports. Severe morbidity was present; three of our patients died, and one had leg amputation. "Residua" were, in fact, residual vascular neoplasia, variable in duration, and not a stable fibrofatty residuum, as in classic involuted hemangioma; only the hematologic phenomenon was "cured" after a period of years.

CONCLUSIONS

KMS is a distinctive disease of infancy, but the underlying vascular lesion is not a "true," classic, involuting type of hemangioma of infancy. This is a different vascular tumor with a resemblance pathologically to either tufted angioma or kaposiform hemangioendothelioma in association with lymphatic-like vessels. Whether the underlying lesion in KMS is a single anatomic entity or heterogeneous cannot be definitely concluded from this study. We need a better understanding of the pathogenesis of KMS to improve our therapeutic management.

Infantile hepatic haemangioendothelioma

Three cases of infantile hepatic haemangioendotheliomas are described. Two demonstrate the natural history of regression of this benign tumour with no associated complication. The last case demonstrates life-threatening complications, which included cardiac failure, thrombocytopenia, disseminated intravascular coagulation and bleeding. Imaging modalities with plain films, ultrasound, computed tomography and angiograms are presented. Pathological findings in two of the cases are also described.