Retro-odontoid Pseudotumor Associated with Sjögren Syndrome and Systemic Lupus Erythematosus Serology

We report here on the first case, to our knowledge, of retro-odontoid pseudotumor (ROP) in a patient with an autoimmune disease other than rheumatoid arthritis (RA). It is possible that the onset of ROP was related to Sjogren syndrome (SS) with serology for systemic lupus erythematosus (SLE). A 34-year-old man presented with an ROP without RA. Three years earlier, he had sicca symptoms and many renal and splenic infarctions, and was diagnosed with SS and antiphospholipid antibody syndrome. The anti-SSA, anti-SSB, anti-dsDNA, anti-RNP, and anti-Sm antibodies and …