Primary T-cell/histiocyte-rich B-cell lymphoma arising in the trigeminal ganglion in a patient with rheumatoid arthritis.

We report a cased of a 68-year-old man with primary T-cell/histiocyte-rich B-cell lymphoma (T/HRBCL) that arose in the trigeminal ganglion. He had a 30-year history of rheumatoid arthritis and presented with progressive left facial pain that had started 3 weeks earlier. Magnetic resonance imaging (MRI) revealed an enhanced mass in the trigeminal ganglion and swelling of the distal part of the trigeminal root. The tumor, subtotally resected via the left anterior petrosal approach, was composed of proliferating CD30- and CD79-positive atypical large polygonal cells with hyperchromatic single or multiple nuclei. CD3-positive small lymphoid cells and CD68-positive histiocytic cells were intermingled with the neoplastic cells. These findings were compatible with T/HRBCL. After whole-brain radiation, his facial pain improved and he was discharged. Postoperatively, he developed transient left sixth nerve paresis. This is the first report of this rare type of B-cell lymphoma arising from the trigeminal ganglion. We posit that his prolonged immunosuppressive treatment for rheumatoid arthritis contributed to its development.