A case of interstitial pneumonia associated with systemic sclerosis and primary peritoneal serous carcinoma successfully treated with cyclophosphamide.

A 62-year-old woman with edema and color changes in her fingers underwent computed tomography (CT); slight interstitial changes were detected in the lungs with multiple tumors in the anterior and hilar region of the liver. Based on the blood test findings, she was diagnosed with interstitial pneumonia associated with systemic sclerosis. Ultrasound-guided biopsy from the hepatic hilar lymph node revealed poorly differentiated serous adenocarcinoma cells. High serum CA-125 levels suggested primary peritoneal serous carcinoma (PPSC). Owing to increased interstitial shadows on chest CT images and worsening respiratory distress, intravenous cyclophosphamide and oral prednisolone treatment was started. The skin-related symptoms, respiratory distress, and interstitial shadows improved, and the tumor size reduced. Eighteen months later, the patient has had no exacerbation of interstitial pneumonia, and the PPSC is well controlled.