Plasma cell granuloma of the lung is an uncommon, slow-growing, benign "pseudotumor" morphologically and clinically distinct from malignant plasma cell tumor (plasmacytoma). Its histopathology is distinct from sclerosing hemangioma and pseudolymphoma. Most are located in lung parenchyma, but a few present as endobronchial lesions. Patients are usually less than 30 years of age. Surgical excision is the preferred treatment and the prognosis is very good. Experience with radiation therapy is limited to one previously reported case. We report a case of plasma cell granuloma of the lung which is unusual because of the patient's age (71 years), endobronchial location, recurrence after local resection, and absence of response to radiation therapy. Ultrastructural features of the lesion are also described.