Abstract
A 59 year-old woman with rheumatoid arthritis (RA) treated with 8 mg/week of methotrexate (MTX) for 4 years visited the department of otolaryngology of our hospital for swelling of her left parotid gland in June 2006. Diagnostic imaging including PET-scans revealed a tumor in the gland. The tumor adhered to the superficial layer of the parotid gland was resected by operation under general anesthesia in July 2006. Pathological diagnosis of the tumor was B cell non-Hodgkin’s lymphoma of low-grade malignancy. Two weeks after MTX was withdrawn from the treatment of RA, arthritis flared and showed resistance to 7 mg/day oral prednisolone.
Therefore, the patient was started on treatment with rituximab (375 mg/m²×4 times/cycle) in May 2007 for both B cell lymphoma and RA. One month after the first cycle of the treatment, the arthritis disappeared, however the symptoms flared up again 6 months later. The second cycle of treatment was started in Jan 2008 and RA has been under control for 6 months. Reoccurrence of lymphoma has not been observed. Rituximab, an anti-CD20 chimeric antibody approved for the treatment of B cell non-Hodgkin’s lymphoma but not for RA in Japan, is considered to be an effective therapy for RA complicated with B cell non-Hodgkin’s lymphoma.
