Breakthrough pulmonary infection with Mucorales while receiving voriconazole for Aspergillus flavus invasive pulmonary infection

65-year-old male underwent heart transplantation for ischemic cardiomyopathy. Posttransplant course was complicated by allograft rejection treated with high-dose glucocorticoids. Patient developed CMV colitis (CMV donor seropositive/recipient seronegative) and invasive pulmonary aspergillosis diagnosed by bronchoalveolar lavage. Chest CT at the time of diagnosis (A) showed consolidative opacities in the right upper lobe (arrow) with additional diffuse nodular opacities. He was treated with valganciclovir and voriconazole. However, follow-up chest CT scan at 3 months (B) revealed resolution of Aspergillus nodules with (C) a new right upper lobe infiltrate (arrow) concerning for breakthrough fungal infection. Bronchoscopy demonstrated a necrotic mass obstructing the anterior segment of the right upper lobe. Microscopy from the lobectomy specimen (D) demonstrated broad, ribbon-like aseptate fungal hyphae (arrow) concerning for mucormycosis, subsequently confirmed by culture. He was treated with surgical right upper lobectomy and liposomal amphotericin and posaconazole.