BACKGROUND: Immunocompromised patients are at increased risk for developing meningitis or, rarely, brain abscess with opportunistic organisms like Listeria monocytogenes.

CASE REPORT: A 52 year-old Saudi Arabian woman who was diagnosed with pemphigus vulgaris and diabetes and had been on prednisolone and azathioprine for about 4 years. She presented with headache, low-grade fever, and left-sided weakness 2 weeks after receiving the second dose of rituximab infusion. Magnetic resonance imaging revealed an enhanced space-occupying lesion with multiple small cyst-like structures and vasogenic edema in the right temporoparietal area. Her blood culture was positive for Listeria monocytogenes, and a brain biopsy showed necrotic tissues with pus and inflammatory cells. She recovered after a 6-week course of antibiotics with ampicillin and gentamycin.

CONCLUSIONS: Brain abscess due to Listeria monocytogenes is a risk that should be considered when adding rituximab to the regimen of a patient who is already Immunocompromised.

Keywords: Antibodies, Monoclonal, Murine-Derived - adverse effects, Antigens, CD20, Brain Abscess - diagnosis, Immunologic Factors - adverse effects, Infusions, Intravenous, Magnetic Resonance Imaging, Pemphigus - complications