A Rare Case of Concurrent Tropheryma Whipplei and Pneumocystis Jirovecii Pneumonia in a Patient During Endocrine Therapy for Breast Cancer

Abstract: Tropheryma whipplei (TW), a rare Gram-positive bacterium, is an uncommon cause of pulmonary infection, typically being reported in the context of gastrointestinal or neurological Whipple’s disease. We present a case of a patient receiving endocrine therapy and ovarian suppression for breast cancer who developed a concurrent pulmonary infection with both Pneumocystis jirovecii (PJ) and TW. The diagnosis was secured through metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid, which successfully identified both pathogens. Following the initiation of targeted antimicrobial therapy, the patient exhibited significant clinical and radiological improvement. Keywords: Tropheryma whipplei, Pneumocystis jirovecii, breast cancer, endocrine therapy, NGS