Pulmonary Mucormycosis Presenting as Rapidly Progressive Cavitary Pneumonia and Lung Abscess in a Patient With Type 2 Diabetes Mellitus and a Solitary Functioning Kidney: A Report of a Rare Case.

Pulmonary mucormycosis is an invasive fungal infection that can present with rapidly progressive pulmonary disease and may mimic bacterial pneumonia or lung abscess. This diagnostic overlap can lead to delayed recognition and treatment. We report the case of a 33-year-old woman with type 2 diabetes mellitus and a solitary functioning kidney, who presented with fever, productive cough, pleuritic chest pain, and progressive dyspnea. Serial chest radiographs demonstrated rapid progression of lung lesions from right-sided consolidation to cavitary necrosis with air-fluid level formation, consistent with lung abscess. Despite broad-spectrum antibiotic therapy, clinical and inflammatory markers worsened, prompting bronchoscopy evaluation. Histopathology revealed broad aseptate fungal hyphae with right-angle branching. Fungal culture confirmed Rhizopus species, compatible with the diagnosis of pulmonary mucormycosis. The patient was treated with intravenous liposomal amphotericin B for six weeks. The therapy was complicated by amphotericin-induced hypokalemia, hypomagnesemia, and transient liver enzyme derangement, necessitating close monitoring given her solitary functioning kidney. She demonstrated gradual clinical and biochemical improvement with appropriate antifungal therapy. This case highlights the importance of early suspicion of mucormycosis in diabetic patients with non-resolving pneumonia and underscores the challenges of managing antifungal therapy in patients with limited renal reserve.