Abstract Introduction Concurrent pulmonary infection with Aspergillus and mucormycosis species is extremely rare and associated with high mortality in immunocompromised hosts. Recent literature describes only a limited number of pulmonary mixed Mucorales-Aspergillus infections, emphasizing the rarity of this presentation. Diagnostic differentiation is challenging due to overlapping radiographic findings and the inability of fungal biomarkers to reliably detect mucor species. Early recognition is critical, as standard aspergillus-directed therapy lacks activity against mucorales, making broad empiric antifungal coverage essential. Case Presentation A 35-year-old woman with relapsed acute myeloid leukemia status post allogeneic stem cell transplant presented with nonproductive cough and dyspnea on exertion. Laboratory evaluation showed leukocytosis, anemia, and thrombocytopenia. Computed Tomography (CT) of the chest demonstrated new multifocal sub-solid nodular consolidations in with tree-in-bud nodularity, concerning for endobronchial infection. Empiric anti-fungal therapy with liposomal amphotericin B and posaconazole was initiated. Bronchoscopy revealed airways filled with thick yellow mucus plugs and occlusion of the left upper lobe orifice by a white pseudomembrane. Bronchoalveolar lavage (BAL) culture grew Cunninghamella bertholletiae. BAL galactomannan was positive, and cytology demonstrated septated hyphae morphologically consistent with Aspergillus species. Pathologic examination of the pseudomembrane showed infarcted necrotic tissue containing fungal elements consistent with Aspergillus. Repeat CT chest performed three weeks after treatment initiation showed interval progression of multifocal pneumonia with new bilateral nodular opacities. Following a goals-of-care discussion, the patient declined further workup or treatment and elected hospice care. Discussion This case highlights the diagnostic complexity of dual invasive fungal pneumonia in severely immunocompromised patients. Overlapping imaging patterns and biomarker limitations can delay recognition of mucormycosis, for which standard aspergillosis therapy is ineffective. Co-infection should be suspected when pulmonary infiltrates progress despite empiric therapy. Early broad antifungal coverage and prompt bronchoscopic evaluation remain essential to improving outcomes in this population. This abstract is funded by: None
Vontela et al. (2026) studied this question.