Fernand Mac–Moune Lai

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.

BACKGROUND: The natural course of adult hepatitis B virus (HBV)-related membranous nephropathy in areas where HBV infection is endemic (characterized by vertical and horizontal transmission of HBV in early childhood) has not been fully defined. METHODS: We evaluated the clinical features, pathological findings, serologic profiles, therapeutic responses, and prognoses of 21 patients with adult-onset HBV-related membranous nephropathy. The patients were followed for a mean of 60 months (range, 12 to 108). Only patients with evidence of glomerular capillary deposition of hepatitis B e antigen (HBeAg) in a renal-biopsy specimen were included. RESULTS: The clinical features and serologic studies suggested that the patients had acquired chronic HBV infection in early childhood; moreover, other causes of membranous nephropathy had been excluded. All were seropositive for hepatitis B surface antigen and had high titers of antibody to hepatitis B core antigen at first clinical presentation. HBeAg was detected in the serum of 17 patients (81 percent), yet only 3 had even slightly increased plasma alanine aminotransferase levels. The clinical response to therapy with interferon alfa was disappointing; only one of the five patients treated had a complete remission with seroconversion to antibody to HBeAg. Contrary to reports of studies in children, spontaneous remission of the nephrotic syndrome or proteinuria was uncommon in the adults with HBV-related membranous nephropathy whom we studied. Proteinuria and HBV antigenemia persisted in untreated patients. During the follow-up period, 29 percent of the patients had progressive renal failure and 10 percent required maintenance dialysis therapy. CONCLUSIONS: The course of HBV-related membranous nephropathy in adults in areas where HBV is endemic is not benign. Regardless of treatment, the disease has a slowly but relentlessly progressive clinical course in approximately one third of patients.