Paclitaxel-Induced Acute Fibrinous and Organizing Pneumonitis in Early Breast Cancer: A Case Report

Background: Paclitaxel is a chemotherapeutic drug widely used in breast cancer treatment. While common side effects are possible, paclitaxel-induced pneumonitis is rare, with an estimated incidence of 1%–5% and a high mortality rate. Case presentation: A 57-year-old Thai woman was diagnosed with stage II right breast cancer. She received adjuvant chemotherapy comprising doxorubicin and cyclophosphamide, followed by weekly paclitaxel. After the ninth paclitaxel cycle, she developed progressive dyspnea and acute respiratory failure. Empirical antibiotic therapy with meropenem, levofloxacin, oseltamivir, and trimethoprim-sulfamethoxazole was initiated to address potential bacterial/viral pneumonias and Pneumocystis carinii pneumonia. Transbronchial biopsies revealed acute fibrinous and organizing pneumonitis. The patient was placed in the prone position, and a muscle relaxant was administered. Following the administration of dexamethasone, her symptoms improved. However, while reducing the dexamethasone dosage, she developed new-onset dyspnea as well as tachy-brady arrhythmia and hypotension. Echocardiography revealed Takotsubo cardiomyopathy (stress-induced cardiomyopathy). Intravenous methylprednisolone 500 mg/day was administered for 3 days followed by transition to intravenous dexamethasone and slow tapering to prednisolone. Prednisolone was gradually tapered and eventually discontinued after 3 months. Discussion: and Conclusions: Paclitaxel-induced pneumonitis is a rare complication. The diagnosis should be considered in any patient who develops respiratory symptoms while receiving paclitaxel. Acute fibrinous and organizing pneumonitis is a rare type of interstitial pneumonitis with high recurrence and mortality rates. High-dose steroids are needed to treat this type of pneumonitis.