The non-Hodgkin's lymphomas encompass a wide spectrum of hematologic neoplasms that exhibit different clinical and biological features. Lymphomas classically have been initially assessed based on their cytologic and histologic features. Morphology alone is often inadequate as similar appearing neoplasms may be immunophenotypically and molecularly heterogeneous. Molecular diagnostic methods can provide an additional level of testing that not only helps refine diagnoses but can provide prognostic information. New methods are being refined that may provide information to establish precise diagnostic profiles, provide targets for therapy and provide more sensitive methods for monitoring the success of treatment. Molecular methods will be increasingly utilized and eventually required as the accepted method of diagnosis and for monitoring the disease. Understanding of the molecular abnormality and the pathogenesis of the neoplasm hopefully will lead to therapeutic intervention aimed at the specific molecular defect or its product. The molecular pathology of the non-Hodgkin's lymphomas is discussed.

One week after the diagnosis of meningococcal meningitis, an 8-year-old boy presented with acute renal failure and hypocomplementemia. A renal biopsy showed "postinfectious glomerulonephritis" and acute tubular necrosis. Hematuria, proteinuria, and low complement levels persisted, and 2 years later a follow-up renal biopsy revealed dense deposit disease. The apparent progression of postinfectious glomerulonephritis to dense deposit disease as observed in this patient has not been previously described.

No abstract