Cladophialophora Brain Infection in a Young Dog Mimics Tumor on MRI

Veterinary Record Case Reports 2022

Author

Obi Veterinary Education
December 28, 2025

Alexis Tolbert, Alisia Weyna, Kaori Sakamoto, Michael Perlini, Simon Platt

Background:
Cladophialophora bantiana is a dematiaceous fungus capable of causing cerebral phaeohyphomycosis, a rare but severe brain infection in animals. Though well-documented in humans, veterinary reports remain scarce. The path of infection is uncertain but may involve inhalation or hematogenous spread. This case report describes the MRI and histopathologic findings of C. bantiana encephalitis in a young, previously healthy dog and highlights diagnostic challenges due to its imaging similarities with neoplasia or sterile inflammation.

Methods:
A 1-year-old neutered male Yorkshire Terrier presented with a 3-week history of neck pain, disorientation, circling, and vestibular signs. MRI of the brain was performed using a 3.0 T scanner. Findings were compared to postmortem histopathology and fungal culture with sequencing. Histological stains (H&E and Grocott’s methenamine silver) were used to confirm fungal presence, and the isolated organism was identified as C. bantiana via sequencing of D1/D2 and ITS regions.

Results:
MRI revealed a large, space-occupying intra-axial mass centered in the left thalamus and hippocampus, with surrounding vasogenic edema, herniation, and restricted diffusion. The lesion showed ring enhancement and a small focal hemorrhagic/calcified area. Histopathology identified pyogranulomatous inflammation with necrosis and septate, pigmented fungal hyphae with right-angle branching, consistent with Cladophialophora spp. Fungal structures were also detected in nasal conchae debris, suggesting possible inhalation as the route of CNS entry. The dog was euthanized due to poor prognosis.

Limitations:
As a single case report, findings are not generalizable. The presence of fungal hyphae in nasal samples may represent postmortem contamination. No CSF analysis was performed due to concern for herniation. Additionally, histological detection of fungal organisms can be inconsistent, and infection may occur in both immunocompromised and immunocompetent animals.

Conclusions:
C. bantiana can cause severe and fatal cerebral infections in young, immunocompetent dogs. MRI findings may mimic neoplasia or sterile inflammation, underscoring the importance of histopathology and fungal culture for definitive diagnosis. Veterinarians should consider cerebral phaeohyphomycosis in differential diagnoses for young dogs with acute neurological signs and intracranial mass-like lesions. Prognosis remains poor, though rare cases of successful treatment have been documented with surgical debulking and antifungal therapy.

(a) Sagittal T2-weighted (T2W) image showing the thalamic mass lesion, cerebellar herniation through the foramen magnum, the hyperintense spinal cord and saccular dilation of the central canal. The orange line in (a) demarks the location of transverse images (b–f). Images (b–f) and (g) are oriented with the left of the patient to the right of the images. (b) Susceptibility weighted imaging (SWI) showing a thin hypointense rim surrounding one of the cystic lesions. (c) T2W transverse (TRV) image showing one of the cystic lesions and mass effect centered at the left thalamus with surrounding oedema tracking along the left corona radiata. (d) T2 TRV fluid attenuated inversion recovery shows hyperintense signal throughout the corona radiata, thalamus and centrally within the cystic lesion. (e) Pre-contrast T1-weighted (T1W) image showing predominantly hypointense signal throughout the corona radiata and the thalamus. (f) Post-contrast T1W image showing the rim enhancing cystic lesion and surrounding lobular homogeneously contrast enhancing regions. (g) Parasagittal image to the left of midline; the yellow line demarks the location of the transverse image (h). (h) SWI image showing a focal signal void with moderate blooming artefact

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