A patient in her 60s was referred to our hospital with pancreatic enlargement. Laboratory data and endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) revealed a nonfunctioning pancreatic neuroendocrine tumor (WHO classification 2010 G2). Resection was contraindicated because of portal vein invasion and extensive collateral vascularization. Everolimus (10 mg/day) was started after seven months of treatment with S-1 (an oral formulation of tegafur with the modulators gimeracil and oteracil) following its insurance approval in Japan. Four months later, the patient developed cough and fever, and there was radiological and clinical evidence of Grade 2 everolimus-associated interstitial pneumonia (according to the Everolimus Proper-Usage Guide). Everolimus was replaced with steroid therapy (30 mg/day), resulting in immediate symptomatic improvement. After conclusion of steroid therapy, everolimus was restarted. The patient has since remained on a dosage of 10 mg/day of everolimus, with the tumor in a state of partial response.