Severe pulmonary toxoplasmosis mimicking viral pneumonitis after a third allogeneic stem cell transplantation in a man with acute lymphoblastic leukemia.

A 22-year-old man with acute lymphoblastic leukemia underwent allogeneic stem cell transplantation (allo-SCT) twice, then underwent allo-SCT a third time due to relapse. On day 27, he developed acute respiratory distress, and bilateral interstitial infiltrates were noted on CT images. Despite receiving intensive treatment, the patient died on day 32 from progressive respiratory failure. An autopsy revealed evidence of diffuse alveolar damage caused by the genus Toxoplasma. At present, toxoplasmosis is considered to be a rare infectious complication in Japan. However, the actual incidence of toxoplasmosis may be higher than currently believed due to a lack of suspicion of the diagnosis in patients, difficulty in making a diagnosis and low autopsy rates.