Walsh & Hoyt: Plasma-Cell Granulomas

Plasma-cell granulomas are rare lesions characterized by plasma cells, histiocytes, and lymphocytes interspersed in a matrix of hyalinized fibrous tissue. They are distinct from plasmacytomas, which contain only plasma cells. Most plasma-cell granulomas occur in the lung or upper respiratory tract, but they may occur in almost every organ, and they occasionally involve the CNS. When they arise in the anterior cranial fossa, they may produce diplopia or loss of vision. MR imaging of these lesions reveals nonspecific features, including high signal intensity on T1-weighted images and low signal intensity on T2-weighted images. The lesions heterogeneously enhance after intravenous injection of gadolinium-DTPA or a similar paramagnetic substance. Diagnosis is almost always made by biopsy. Treatment is surgical resection followed by radiation therapy. The prognosis of these benign lesions is excellent.