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

Successful treatment of an adult with Kasabach-Merritt syndrome using thalidomide, vincristine, and prednisone

Objective

Kasabach-Merritt syndrome is a rare disease that mainly occurs in infants and adolescents. It usually manifests as disseminated intravascular coagulation and severe bleeding, and is associated with high mortality. However, its low incidence and clinical rarity in adults mean that there is currently no well-verified treatment regimen for this disease. We report on an effective novel therapeutic regimen in a patient with Kasabach-Merritt syndrome.

Methods

A woman with Kasabach-Merritt syndrome presented with a recurrent subcutaneous mass and disseminated intravascular coagulation, and was treated with prednisone, vincristine and thalidomide.

Results

This treatment regimen successfully resolved the patient’s symptoms, with tumor regression. The patient remained disease-free after 6 years of follow-up.

Conclusions

Prednisone combined with vincristine and thalidomide may be an effective treatment for Kasabach-Merritt syndrome, but further studies are needed to verify the use of this regimen.

A Case Report of 2 Sirolimus-Related Deaths Among Infants With Kaposiform Hemangioendotheliomas

Kaposiform hemangioendothelioma (KHE) is a rare infiltrative vascular tumor that is potentially life-threatening when presenting with Kasabach-Merritt phenomenon (KMP). KMP is clinically characterized as severe thrombocytopenia and hypofibrinogenemia and therefore is associated with a high mortality rate. There is no standard of cure for KHE currently. Potential medications, including corticosteroids, propranolol, and chemotherapy drugs such as sirolimus, are often used for alleviating KHE symptoms. Although some case reports of sirolimus treatment have shown promising results with recovered coagulant parameters, the off-target effects may cause severe problems. Here we describe 2 cases of infant patients with KHE and KMP who were scheduled to receive sirolimus on a long-term basis. However, both patients developed paroxysmal cough and tachypnea shortly after the onset of sirolimus treatment and succumbed to infection thereafter. This report reveals a potential risk of infection in sirolimus-treated infant patients. The fatal complication highlights the importance of antibiotic prophylaxis and serum sirolimus level monitoring to ensure the safe use of sirolimus in the treatment of infant patients with KHE.

Successful surgical management of congenital Kasabach-Merritt syndrome

Since the first description of Kasabach-Merritt syndrome (KMS) in 1940, many treatments have been proposed combining pharmacologic and non-pharmacologic approaches, which can be effective on the pathology but can have adverse and unpredictable side-effects with long-term use. Herein we describe the solely surgical treatment of Kasabach-Merritt syndrome in a neonate with a severe and rapidly progressive thrombocytopenia. The patient's condition normalized at 7 days postoperatively, with rapid increase in platelet count and normalization of d-dimer concentration.

Kaposiform hemangioendothelioma with distant lymphangiomatosis without an association to Kasabach-Merritt-Syndrome in a female adult!

Kaposiform hemangioendothelioma (KHE) is a locally aggressive vascular tumor which usually occurs in infants. Clinically it appears as ill-defined red to purple indurated plaque. KHE is commonly associated with Kasabach-Merritt syndrome (KMS) and lymphangiomatosis. Microscopically, the tumor is composed of infiltrating lobulated nodules with slitlike or crescentic vessels which are poorly canalized and lined by spindle shaped endothelial cells. We report a 36-year old female who developed a reddish tumor on the chest. Histological examination revealed a KHE, which was clinically not associated with thrombocytopenia or bleeding complications, but lymphangiomatosis at the right submandibular region. The association of KHE in a female adult with lymphangioma rather than KMS in this case supports the hypothesis that such an association may represent a benign subform of this disease in an adult and excision seems to be curative.

Kaposiform hemangioendothelioma without Kasabach-Merritt phenomenon

Kasabach-Merritt phenomenon is a serious coagulopathy associated with kaposiform hemangioendothelioma (KHE), tufted angioma, and possibly other vascular neoplasms. KHE presenting in the absence of Kasabach-Merritt phenomenon is rare, although tufted angioma frequently occurs without thrombocytopenia. We retrospectively reviewed 10 cases of KHE without Kasabach-Merritt phenomenon. The tumors appeared as soft tissue masses with the overlying skin being either normal, erythematous, or violaceous. There were no radiologic or microscopic differences in noncoagulopathic KHE as compared with coagulopathic KHE. Evidence of platelet trapping and hemosiderin deposition was seen histologically, despite normal serum platelet levels. All KHE were less than 8 cm in diameter, suggesting that tumors that grow no larger than this size are less likely to trap platelets in sufficient quantity to cause thrombocytopenia. Our series confirms that KHE appears with a wide spectrum of behavior and response to treatment. The decision as to whether or not to treat a noncoagulopathic KHE should be based on the size and location of the tumor and the possible side effects of therapy.

Hemangiomas: new insights and classification

Infantile hemangiomas are the most common tumors of infancy, but less common vascular tumors also can affect young infants and children. In most cases, the diagnosis of IH can be made clinically, but imaging studies and even biopsy may be required in less-than-typical cases. With a careful history and physical examination focusing on the timing, location, and type of hemangioma, as well as extracutaneous signs and symptoms, the general pediatrician will know when to be concerned about a high risk vascular tumor and proceed with referral or further evaluations.

Kaposiform Hemangioendothelioma

Kaposiform hemangioendothelioma (KH) is a rare tumor of childhood often associated with Kasabach-Merritt phenomenon (KMP) and occasionally lymphangiomatosis. Although generally considered distinct from other vascular neoplasms, its rarity has precluded a thorough study of its immunophenotypic profile and long-term behavior. Thirty-three cases of KH were reviewed and immunostained for alpha-smooth muscle actin, various endothelial markers (CD31, CD34, vWf, FLI1), a platelet marker (CD61), and the juvenile hemangioma-associated markers GLUT-1 and Lewis Y antigen (LeY). In addition, the presence of HHV-8 was evaluated by RT-PCR. The patients (20 males and 13 females) ranged in age from 2 weeks to 20 years (mean 3 years 9 months). Tumors developed on the extremities (17 cases), head/neck (8 cases), and other sites (8 cases) and affected both superficial and deep soft tissue. Those in the skin presented as slightly raised blue-red lesions. More than half of the patients presented with KMP (14 of 25). Tumors consisted of irregular, infiltrating nodules of compressed vessels, which modulated between areas resembling a capillary hemangioma and Kaposi sarcoma (KS). Endothelial cells in nodules were CD31, CD34, and FLI1 positive but negative for GLUT1 and LeY. Scattered "epithelioid" or glomeruloid islands featuring endothelium associated with clusters of plump alpha-smooth muscle actin-positive pericytes, stippled hemosiderin, and CD61-positive fibrin thrombi likely represent the morphologic sites of platelet consumption. Small and large lymphatic channels occurred in 22 of 33 cases and were typically seen peripheral or deep to the main tumor mass. HHV-8 transcripts were not identified (0 of 3 cases). Follow-up information was available in 22 patients (range 8 months to 15 years; mean 2 years) and indicated that 3 died of disease, 8 were alive with disease, and 10 were alive without residual disease. Two patients developed regional perinodal soft tissue involvement, but none developed distant metastases. KH is a lesion having both a vascular and lymphatic component. Its common association with KMP probably relates in part to unique architectural features that favor turbulent blood flow and platelet activation. KH can also be reliably separated from JH by GLUT-1 and LeY immunostaining, indicating differences in the morphologic and functional attributes of the endothelium between the two lesions. The absence of HHV-8 in KH underscores a different pathogenesis from Kaposi sarcoma. Our study, the largest to date, emphasizes that mortality is due to KMP and not metastatic disease, which appears limited to regional perinodal soft tissue. Given this behavior, its continued classification as a vascular tumor of intermediate malignancy is warranted.