RESUMO
We describe a 40-year-old woman with polymyositis (PM) who developed autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC), and autoimmune thrombocytopenic purpura (AITP) concurrently. About 4 years earlier, she suffered from muscle weakness probably due to PM. When she visited our hospital, she had polyarthritis, myalgia, symmetrical proximal limb-muscle weakness, elevated muscle enzymes, and myogenic abnormalities on electromyogram. Pathological findings obtained by muscle biopsy showed histological findings consistent with PM. Her serum liver enzymes were also elevated. The histology obtained by liver biopsy revealed the mixture findings of chronic active hepatitis and biliary cirrhosis. As antibodies to mitochondria M2 and liver/kidney microsome type 1 (LKM-1) were present, we concluded her liver disease was due to an overlap of AIH and PBC. Furthermore, purpura on the legs with thrombocytopenia appeared in parallel with liver dysfunction. She was diagnosed as having AITP by clinical and laboratory findings. Her serum showed a speckled pattern in immunofluorescence antinuclear antibody testing, but the antigen specificities were distinct from those of the known myositis-related autoantigens. This is a first case report of PM accompanied by AIH, PBC, and AITP. It was notable that there was an overlap of disease-associated immunological findings and immunogenetic backgrounds. This case provides a possible insight into the mechanisms and interplay of autoimmune diseases.