Isolated cerebellar mucormycosis, slowly progressive over 1 year in an immunocompetent patient

Abstract

Background: Mucormycosis is a rare, aggressive fungal disease with high mortality, typically presenting as rhinosinusitis in immunocompromised patients.

Case description: A 43-year-old man with a history of intravenous drug use, Hepatitis C, and no evidence of immunocompromise presented with worsening balance problems. He had received intravenous antibiotics 2.5 years earlier for local infection after injecting heroin into a neck vein. Imaging studies revealed a lesion, likely of neoplastic origin. At resection, purulent fluid sampled by neuropathology revealed right-angled, branching hyphae, suggesting mucormycosis. No further resection was performed, no other disease sites were found, and HIV findings were negative. Two weeks postoperatively, he developed renal failure; intravenous antifungal treatment and hemodialysis were discontinued. When kidney function recovered 2 weeks later, he declined additional treatment.

Conclusion: In our immunocompetent patient, both the location of the infection in the posterior fossa and its slowly progressive characteristic were unique variations of this typically aggressive disease.

Keywords: Fungal; immunocompetent; infection; intravenous drug abuse; mucormycosis; rhinocerebral.

Figure 1

Early MRI evaluation in a 43-year-old man with balance problems and a history of IVDA. T2-weighted axial image at the level of the craniocervical junction (A) with dorsally located hypointensity (arrow) with corresponding true diffusion restriction as seen on diffusion weighted imaging (B), and apparent diffusion coefficient (C) images. Subtle increase in FLAIR signal (D) is noted in the left cerebellar hemisphere (arrowhead). Encephalomalacia from the remote infarct is seen in the left parietal lobe is also seen.

Figure 2

Nine months later, preoperative MRI T1-weighted contrasted axial images showing the enhancing nodular mass in the cerebellar vermis (A) and (B). T2-weighted image showing persistent hypointensity (C) with superior extension (D). Increased FLAIR signal abnormality in the cerebellar hemisphere (E). Before surgery, believed to be neoplastic; at surgery, abnormal tissue with pockets of purulent fluid observed.

Figure 3

Pathologic sample shows branching hyphae suggesting mucormycosis (arrow). (H&E, ×200)