Severe Enteritis after Cyclophosphamide Administration in a Patient with Microscopic Polyangiitis: A Case Report and Literature Review.

Severe enteritis is a rare side effect of cyclophosphamide (CPA) therapy, and only two cases have been reported to date. We herein report a 60-year-old man who developed severe enteritis after intravenous CPA administration for microscopic polyangiitis. He was successfully treated by discontinuation of CPA administration and long-term intensive supportive care. A diagnosis of CPA-associated enteritis was made based on the clinical course and imaging and pathological findings. This review of three cases of CPA-related enteritis, including our case, suggests that prompt CPA discontinuation and intensive systemic management are necessary when patients have gastrointestinal symptoms after CPA administration.