Primary pleural non-Hodgkin lymphoma in a child--an exceedingly rare disease. 
Primary pleural lymphomas are very rare.  Two types are described in the literature: primary effusion lymphoma, in the setting of human immunodeficiency virus infection, and pyothorax-associated lymphomas, with a strong Epstein-Barr virus association.  We report a rare case of a primary pleural lymphoma in a 12-year-old immunocompetent girl who presented with a hemorrhagic pleural effusion and had plaque-like thickening of the pleura.  The histologic and immunophenotypic findings conformed to that of a diffuse large B-cell lymphoma (CD20 positive).