Primary biliary malignant lymphoma clinically mimicking cholangiocarcinoma: a case report and review of the literature.

Primary lymphomas of the liver and biliary tract are rare tumors. We describe an unusual case of a diffuse large B-cell lymphoma arising in the extrahepatic bile ducts with local extension to involve the intrahepatic bile ducts. The patient presented solely with obstructive biliary symptoms. The clinical presentation, radiographic studies, and gross findings at surgery suggested that this patient had a Klatskin tumor (cholangiocarcinoma arising at the junction of the left and right hepatic ducts). While rare, the difference in initial patient management emphasizes the importance of including malignant lymphoma in the differential diagnosis of obstructive biliary lesions. Ann Diagn Pathol 5:25-33, 2001.

Glomerular membranopathy in children with IgA nephropathy and Henoch Schönlein purpura.

We evaluated renal biopsies from 34 children with IgA nephropathy or Henoch Schönlein purpura to further characterize the ultrastructural features of the glomerular membranopathy that occurs in these disorders. Focal glomerular basement membrane damage was identified in 29 children and was severe in 4 of the children. Alterations included focal and segmental attenuation, splitting, duplications, and spike-like subepithelial protrusions of the lamina densa, along with saccular glomerular microaneurysms arising at the paramesangium. Those cases with extensive glomerular basement membrane lesions had either moderate or severe glomerular alterations apparent by light microscopy. Over half of the cases with glomerular membranopathy had immunohistological or ultrastructural evidence of focal peripheral glomerular capillary wall immune deposits and electron-dense deposits occurred at sites of glomerular basement membrane splitting. Despite the focal attenuation of the glomerular basement membrane, we did not identify any biopsy with findings of thin basement membrane disease. The glomerular basement membrane ultrastructural findings we describe are characteristic of IgA nephropathy and Henoch Schönlein purpura, are common in children with these disorders, and are similar to the ultrastructural alterations of the basement membrane that occur in other glomerulonephritides. These basement membrane injuries may be inflammatory cell or immune mediated but their pathogenesis requires further study.