A rare case of concurrent plasma cell granulomas (PCG) of the lung and the central nervous system (CNS) is reported. A 30-year-old man was presented with recurrent left headaches lasting for two years. Computerized tomographic (CT) scan and magnetic resonance imaging (MRI) of the head disclosed a process extending from the lateral aspect of the left cavernous sinus to the tentorium cerebelli and the infratemporal fossa through the foramen ovale. At the same time, chest-X ray and CT scan showed three symptomless masses of the pulmonary right lower lobe. Histological examination of cerebral samples and of one of the pulmonary nodules revealed the presence of a fibrous tissue containing numerous lymphocytes and plasma cells as well as remnants of vascular and respiratory structures. Immunohistochemical study proved these cells to be polyclonal. Ultrastructural analysis confirmed the presence of lymphoid cells and failed to disclose any argument for meningioma or histiocytosis X. The differential diagnostic problems of PCG are discussed as well as considerations about clinicopathological features, histogenesis and pathogenesis of inflammatory pseudotumours (IPT).