Interstitial pneumonitis associated with mitomycin C and DTIC: a case report

A case of interstitial pneumonitis secondary to mitomycin C and DTIC combination therapy in a 58-year-old male with metastatic adenocarcinoma of the rectum is reported. Dry cough and dyspnea, especially on exertion, were presenting symptoms. Arterial blood gas analysis was compatible with severe impairment in pulmonary diffusion capacity. Chest x-ray showed a diffuse increase in interstitial markings in both lung fields consistent with interstitial pneumonia. Histologically, prominence of type I pneumocytes, focal proliferation of type II pneumocytes, and varying degree of fibroblastic proliferation and collagenization within the alveolar septae were observed. The obliteration of alveolar septal vessels due to endothelial edema and/or proliferation of fibroblast-like mesenchymal cells were also noted. Withdrawal of drugs and institution of high dose corticosteroid therapy were followed in rapid improvement in dyspnea and arterial blood gas findings. If diagnosed early, this potentially life threatening complication may respond to such therapy.