Use of Rituximab in a Sjogren's Disease-Associated Inflammatory Pseudotumor: A Case Report.

Inflammatory pseudotumors are uncommon but benign tumors that consist of a proliferation of inflammatory and spindle cells, and they are a rare occurrence in Sjogren's disease (SjD). We report a rare case of a SjD-associated inflammatory pseudotumor in the pleural space, which caused mass effect-related discomfort in this patient. A 74-year-old female patient with an extensive history of SjD presented with chronic neck and back pain and inflammatory arthralgias. Further imaging showed a right-sided, paraspinal soft-tissue mass in the pleural space, raising concern for a possible malignancy. The tumor histopathology revealed a blend of spindle cells, inflammatory infiltrate, and fibrous tissue, and she was eventually diagnosed with an inflammatory pseudotumor. She was initially treated with corticosteroids, which shrank the tumor. However, steroid tapering resulted in the reoccurrence of arthralgias. She was then initiated on rituximab, resulting in an excellent clinical outcome and continued shrinkage of the pseudotumor. This case suggests that rituximab is a possible consideration in the treatment of SjD-related inflammatory pseudotumors and inflammatory arthralgias, especially when continuous corticosteroid therapy is not ideal.