Evolution of pulmonary pseudolymphomas: clinical and radiologic manifestations.

Solitary or multifocal pulmonary pseudolymphoma developed in two men and two women between 59 and 76 years of age. The lesions were detected incidentally in three patients and following a respiratory infection in the fourth. Follow-up radiographs and chest CT revealed gradual expansion of the opacities without cavitation, calcification, or pleural involvement. Histopathologic sections from open lung biopsies or resected segments showed dense alveolar and peribronchial infiltration by numerous mature lymphocytes and plasma cells surrounding reactive lymphoid follicles with true germinal centers. Their benign nature was confirmed by immunofluorescent studies showing polyclonal cell populations. No recurrence or malignant change occurred during 4- to 9-year periods of observation. The clinical and radiologic features of pulmonary pseudolymphoma are presented with a brief review of 54 previously reported cases.