Brain Abscesses Caused by Nocardia farcinica in a 44-Year Old Woman with Multiple Myeloma: A Rare Case and Review of the Literature.

BACKGROUND Central nervous system infection by the Nocardia species is associated with high morbidity and mortality. Its occurrence in patients with multiple myeloma is rare and acquisition of the infection in such patients was associated with the use of novel therapeutic agents (eg, bortezomib and lenalidomide) or bone marrow transplantation. Here, we report the first case of Nocardia brain abscesses in a patient with multiple myeloma, without the above risk factors. CASE REPORT A 44-year-old woman with IgG-kappa type multiple myeloma presented with generalized tonic-clonic seizures. Magnetic resonance imaging of the brain revealed 3 space-occupying lesions in left frontal, left parietal, and right parietal regions. Craniotomy and enucleation of the left frontal lesion revealed an abscess. The culture result was Nocardia farcinica. The patient was treated with meropenem, amikacin, and trimethoprim-sulfamethoxazole for 6 weeks, followed by trimethoprim-sulfamethoxazole for 12 months, with good outcome. CONCLUSIONS Cerebral nocardiosis is a rare entity and its occurrence in our case may hint toward myeloma-associated humoral immune dysfunction as a pathogenesis and the importance of humoral immunity in the defense against this infection. However, chemotherapy-induced cell-mediated dysfunction cannot be ruled out as a risk factor for the infection. Despite its rarity, this case aims to raise awareness of the condition and reiterate the importance of considering the rare but life-threatening conditions in the differential diagnosis of brain lesions, especially when there is a misdiagnosis of the radiological findings, as occurred in this and previous cases; this avoids delays in appropriate surgical and medical treatment, which can affect outcomes.