The Kasabach-Merritt syndrome: treatment with intermittent pneumatic compression

Non-traumatic splenic rupture in a patient with Kasabach-Merritt syndrome

This report presents a case illustrating the complications of Kasabach-Merritt syndrome in a 22-year-old man. The patient presented with acute abdominal pain and profound anaemia; a CT scan revealed intraperitoneal bleeding from spontaneous splenic rupture. The patient underwent initial emergency laparotomy and splenectomy, with a subsequent further laparotomy to control haemorrhage. Blood products requirements were extensive: 28 units red blood cells, 14 units fresh frozen plasma, 10 units platelets, 10 units cryoprecipitate and 2× Novo VII. He was then transferred to a nearby tertiary care unit for further management to control his coagulaopathy and he made a full recovery after 4 weeks.

Les complications des hémangiomes

Hemangioma (HMG) is a benign tumour of the child generally evolving to spontaneous regression. Sometimes this evolution can become complicated in a more or less serious way according to its localization or of its importance. If local complications are, in the most of cases, without gravity, complications of a general nature like thrombopenia or cardiac failure may compromise the vital prognosis. There are in addition serious forms where, according to its localization or its importance, the HMG can compromise the aesthetic, or functional even vital outcome.

Successful surgical excision of a complex vascular lesion in an infant with Kasabach-Merritt syndrome

Kasabach-Merritt syndrome, the association of a vascular lesion and consumptive coagulopathy, can represent a diagnostic and therapeutic challenge to clinicians. We describe an infant with a large complex vascular lesion of the left forearm that was successfully surgically excised. We propose surgical excision as an appropriate therapeutic option for some cases of Kasabach-Merritt syndrome.

Case report: Kasabach-Merritt syndrome: a review of the therapeutic options and a case report of successful treatment with radiotherapy and interferon alpha

We describe the successful treatment of a neonate with Kasabach-Merritt syndrome who received local irradiation and interferon alpha therapy after failure of corticosteroid treatment. A male neonate, born after an uneventful pregnancy, had a huge haemangioma involving the upper right cervical region as well as severe thrombocytopenia. He was treated with corticosteroids, interferon alpha and radiotherapy. Prednisolone therapy (5 mg kg(-1) day(-1)) was started at 41 days of age. No therapeutic effect was observed after 2 weeks. At this time the tumour size had increased dramatically, platelet counts had decreased progressively and coagulation abnormalities had developed. Because corticosteroid therapy had been ineffective and the child was in a life-threatening condition, irradiation was delivered up to a total dose of 9.5 Gy in five fractions. Simultaneously, prednisolone therapy was slowly decreased and interferon alpha therapy (3 million U m(-2) day(-1)) was started and continued for 6 weeks. After irradiation with 9.5 Gy and beginning interferon alpha therapy, the tumour decreased in size and coagulation parameters normalized within 4 weeks. 6 months later, platelet counts and coagulation parameters were still normal. The tumour had further decreased in size. No acute severe side effects were observed. Radiation therapy combined with interferon alpha treatment is an alternative treatment modality when high dose corticoid steroid therapy has been ineffective in patients with Kasabach-Merritt syndrome, despite the risks of growth delay and secondary malignancy. In children showing no response to corticosteroids, radiotherapy and/or interferon alpha should be considered in Kasabach-Merritt syndrome.

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.

Outcome of radiation therapy for patients with Kasabach-Merritt syndrome

PURPOSE

The efficacy of radiation therapy for Kasabach-Merritt syndrome, which is characterized by a huge hemangioma with consumption coagulopathy, remains controversial. In this study, we retrospectively investigated the treatment outcome of radiation therapy for seven neonates with Kasabach-Merritt syndrome.

METHODS AND MATERIALS

During the past 25 years we have seen seven children with Kasabach-Merritt syndrome who were treated with radiation therapy. Their ages ranged from 1 day to 5 months, with a median age of 1 month. The hemangioma was located in the extremities in four of seven children. Tumor sizes ranged from 70 cm to more than 150 cm in greatest diameter. Initial platelet counts were all less than 40,000/mm3 except for one patient. In principle, the total dose applied to the hemangioma was 8-10 Gy, with a daily dose of 1 Gy five times a week.

RESULTS

Four of seven hemangiomas responded dramatically, with a concomitant rise of the platelet count to radiation therapy. Although the remaining three hemangiomas, all of which were ill circumscribed by widespread overlying shiny, dusky purple skin, became less tense during radiation therapy. Disseminated intravascular coagulopathy was not improved, but they have responded favorably to two or three courses of radiation therapy with an extended radiation field by 1.5 years of age. As a result, all seven patients are now surviving with no evidence of hemangioma or hematological abnormalities. Shortening of the extremity was observed in three patients who received multiple courses of radiation therapy.

CONCLUSIONS

Radiation therapy appears to be one of the effective treatment options for Kasabach-Merritt syndrome despite the risk of growth delay and malignancy.

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.

Mice with hemangiomas induced by transgenic endothelial cells. A model for the Kasabach-Merritt syndrome

Inoculation of an established endothelial cell line from transgenic mouse hemangiomas (Py-4-1) into histocompatible mice induced vascular tumor formation at the site of infection with 100% frequency. Histological and hematological studies revealed that the mice developed hemangiomas with hematological changes similar to those found in the Kasabach-Merritt syndrome in humans, including hemolytic anemia and thrombocytopenic purpura. Modifications in the red blood cell count, hemoglobin concentration, hematocrit, and platelet count were directly correlated with the size of the hemangioma. Thus transgenic endothelial cell injection into histocompatible mice provides an in vivo model system to study the pathobiology of hemangiomas as well as the investigation of angiogenesis inhibitors.

Serious childhood angiomas: unsuccessful alpha-2b interferon treatment. A report of four cases

Over a 4-year period, we managed four children with alarming haemangiomas (two cases of Kasabach-Merritt syndrome and two life-threatening haemangiomas). Systemic steroid therapy was ineffective. Other treatments (radiotherapy, anti-platelet drugs) were also ineffective in the Kasabach-Merritt patients. On the basis of recent reports on the effects of interferon on endothelial cells, we used alpha-2 interferon therapy, but obtained no response.

Long term follow-up of a case of Kasabach-Merritt syndrome successfully treated with radiotherapy and corticosteroids

Kasabach-Merritt syndrome is the association of thrombocytopenia, spontaneous bleeding, and enlargement of a haemangioma. It is caused by an intense, self-perpetuating process of clot-formation and lysis within the abnormal vascular channels of the haemangioma, and results in consumption of platelets and clotting factors. Treatment involves ablation of the lesion with or without pharmacological manipulation of the coagulation and fibrinolytic systems. No single therapeutic modality is universally successful but a combination of radiotherapy and corticosteroids can result in a dramatic, immediate response with minimal long term complications.

Hemangiomas and vascular malformations

Vascular lesions in the neonate and infant are categorized as hemangiomas or malformations. Although their appearances may be similar, the pathobiology, natural history, and prognosis of these lesions are different. Selected important syndromes that are characterized as hemangiomas and vascular malformations are discussed, and an update on what is new in treatment, including laser therapy, is presented.