A case of splenic infarction possibly attributable to Mycoplasma pneumoniae infection without accompanying pneumonia

We report a case of a patient with splenic infarction possibly attributable to Mycoplasma pneumoniae infection without accompanying pneumonia. A 24-year-old man was admitted to our hospital with a 7-day history of fever, sore throat, and left upper-quadrant abdominal pain. Chest radiography revealed no active lung lesions; however, abdominal computed tomography showed hepatosplenomegaly with splenic infarction. At the time of admission, the patient's serum IgM titer for M. pneumoniae was 79.7 U/mL (positive titer > 70 U/mL). Two weeks later, the serum IgM titer for M. pneumoniae had markedly increased to 3,158.1 U/mL. The patient was treated with azithromycin, and his symptoms began to improve. After 5 weeks, the spleen size decreased, and a scar was observed at the site of the infarct.