Successful reintroduction of mesylate imatinib after pneumonitis in two patients with gastrointestinal stromal tumor (GIST)

: We report 2 cases of successful reintroduction of mesylate imatinib for gastrointestinal stromal tumor (GIST) after drug-induced pneumonitis. Both of them were women in the fifth decade who had been medicated by mesylate imatinib about for 5 months previously, and had been given a diagnosis of imatinib mesylate-induced pneumonitis. After only cessation of that drug, symptoms and shadows on chest X-ray film improved. However, we had to reintroduce the drug because of the growth of primary tumor, so we gave half the previous dose of imatinib mesylate, with low dose prednisone. There has been no recurrence of drug related pneumonitis and effective control of the primary tumor was obtained. The evidence acquired from our cases suggests that it may be possible to reintroduce imatinib mesylate carefully by adjusting the dose with low dose prednisone in a GIST patient, without causing recurrence of drug-induced pneumonitis.