Cryobiopsy for diagnosing acute fibrinous and organizing pneumonia during breast cancer treatment: A case report

Current standard treatments for breast cancer have the potential to induce interstitial pneumonia. The present report describes a case of acute fibrinous and organizing pneumonia (AFOP) in a 52-year-old female patient undergoing adjuvant therapy with abemaciclib following breast cancer surgery. The patient received abemaciclib after completion of radiation therapy. On the 85^th day of abemaciclib administration and 157^th day after radiation therapy initiation, the patient presented with dyspnea. CT findings were indicative of interstitial pneumonitis, warranting hospitalization. During hospitalization, transbronchial lung cryobiopsy (TBLC) was performed, which revealed pathological findings consistent with AFOP. Following two 3-day doses of 1 g intravenous methylprednisolone therapy, tacrolimus (2 mg/day) was administered and the patient was switched to oral prednisolone. The patient was discharged on the 25^th day of hospitalization. Advances in bronchoscopic techniques, including TBLC, may aid in diagnosing lung injuries.