SHM Converge Scientific Abstract ePoster Gallery-Disseminated Blastomycosis Presenting With Central Nervous System Involvement

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A 58-year-old immunocompetent man with well-controlled type 2 diabetes, hypertension, and dyslipidemia presented with months of chronic cough followed by 4 days of right-sided headache, nausea, vomiting, and disequilibrium. He was afebrile with stable vital signs, but exam showed a wide-based gait. Initial labs were largely unrevealing, including no leukocytosis, with mildly elevated inflammatory markers.<br /><br />Chest CT showed a left perihilar mass-like consolidation with tree-in-bud nodules, raising concern for metastatic malignancy, atypical infection, or sarcoidosis. A broad infectious workup, including cryptococcal antigen, toxoplasma serologies, Quantiferon Gold, galactomannan, and urine Histoplasma antigen, was negative. Brain MRI revealed multiple ring-enhancing lesions in the cerebellar vermis with vasogenic edema and mass effect, plus mild ventricular dilation, further mimicking metastatic disease.<br /><br />Because his neurologic exam remained stable, neurosurgery deferred brain biopsy. Bronchoscopic lung biopsy demonstrated a hyalinized granuloma, and fungal culture from lung tissue grew rare Blastomyces dermatitidis, confirming disseminated blastomycosis with CNS involvement. Treatment began with liposomal amphotericin B, but this was switched to isavuconazole due to nephrotoxicity. Dexamethasone was given for cerebral edema. He was discharged on isavuconazole and dexamethasone with follow-up in infectious disease and neurology clinics.<br /><br />This case highlights that CNS blastomycosis can present with ring-enhancing brain lesions and mimic metastatic lung cancer, even in immunocompetent patients. In endemic regions such as the Midwest, clinicians should consider Blastomyces in the differential diagnosis of pulmonary masses and brain lesions. Antigen testing may be negative, and tissue culture remains the diagnostic gold standard.

Asset Subtitle

Ryan M. Welsh

Meta Tag

Author List Ashley A. Narsinghani, Claudia A. Sanchez, Ryan M. Welsh, Zachary Perbohner

Category Clinical Vignettes

Concept Disseminated Blastomycosis

Concept Central Nervous System Involvement

Concept Tissue Culture

Concept Ring-Enhancing Brain Lesion

Concept Amphotericin B

Distinguished Non-Finalist

Presenter Organization Rush Medical College

Presenting Author Ryan M. Welsh

Track Adult

Keywords

blastomycosis

Blastomyces dermatitidis

ring-enhancing brain lesions

disseminated fungal infection

central nervous system involvement

pulmonary mass

tree-in-bud nodules

immunocompetent patient

liposomal amphotericin B

isavuconazole

Disseminated Blastomycosis

Central Nervous System Involvement

Tissue Culture

Ring-Enhancing Brain Lesion

Amphotericin B