MICROSCOPIC DESCRIPTION:
Sections of the lung biopsy showed expansion of the alveolar septa by multifocal dense nodular and diffuse interstitial infiltrates (Image 01) composed of mature lymphocytes and plasma cells (Images 02, 03, and 04). Multiple lymphoid aggregates (Image 05) with active germinal centers (Images 06 and 07) were also seen. Secondary inflammatory changes included abundant collections of histiocytes (Image 08) and focal prominent type II pneumocyte hyperplasia (Image 09).
