Abstract
An 82-year-old man who had advanced gastrointestinal stromal tumor (GIST) received chemotherapy with imatinib mesylate. CT scan showed remarkable tumor shrinkage after 2 weeks of the treatment and the treatment was continued. He developed, however, exertional dyspnea and cough after 35 days of the therapy with the agent. Three days after the onset of those symptoms, marked hypoxemia and bilateral interstitial filtrate on chest CT examination appeared and he was hospitalized. The diagnosis of drug-induced pneumonitis was strongly suggested, so that the agent was discontinued. He received mechanical ventilation for 6 days and corticosteroid therapy consisting of methylprednisolone (1g·day-1) for 3 days, followed by administration of prednisolone. These treatments were effective for respiratory failure and they achieved almost complete recovery from the respiratory failure symptomatically and radiographically. These findings suggested that the patient had drug-induced interstitial pneumonitis caused by imatinib mesylate. Imatinib mesylate was restarted with steroid subsequently and he is now in good health. Although there are several reported cases of interstitial pneumonitis by imatinib mesylate as far as we know, careful attention must be taken for the early identification of such adverse effect during imatinib mesylate therapy.
