RESUMEN
We report an unusual case of overlap syndrome that had the coexistence of five autoimmune diseases. A 45-year-old woman initially developed seropositive erosive rheumatoid arthritis (RA) 11 years ago. She then developed progressive systemic sclerosis (PSS) (including pulmonary hypertension, esophageal dysfunction, cardiac involvement and sclerodactilitis), systemic lupus erythematosus (SLE) (including photosensitivity, nephritis, leukopenia, lymphopenia, thrombocytopenia and Coombs positive hemolytic anemia and positive anti-dsDNA), and secondary Sjögren's syndrome (SSS) in the last 7 years before she was admitted to our clinic. The patient fulfilled classification criteria for RA, SLE, PSS and SSS, as determined by American College of Rheumatology. Hypothyroidism with positive autoantibodies due to Hashimoto's thyroiditis, the beginning of which could not be defined, was coexistent with this overlap syndrome. In the literature, although overlap syndromes in different combinations were reported, we very rarely observed a complex case like this patient. In our opinion, this is the first well-documented case of RA, PSS, SLE, SSS and Hashimoto's thyroiditis existing together in the same patient. Although immunosuppressive therapy was administered, the disease rapidly deteriorated and the patient died.