Solitary Nocardia farcinica brain abscess in an immunocompetent adult mimicking metastatic brain tumor: rapid diagnosis by pyrosequencing and successful treatment.
BACKGROUND
Nocardia brain abscess carries a higher morbidity and mortality rate than other bacterial cerebral abscesses, with reported mortality rates of 55% and 20% in immunocompromised and immunocompetent patients, respectively. To prevent a delay in diagnosis and treatment, an aggressive therapeutic approach is required. In the present study, a rapid and accurate molecular diagnostic approach using pyrosequencing (PS), a semiautomated molecular genotyping method of nucleotide sequencing-by-synthesis, was performed.


METHODS
A 53-year-old man developed word-finding difficulties, followed by confusion and disorientation. On examination, the patient had a mixed aphasia; the receptive component was greater than the expressive component. The remainder of his neurologic examination findings was normal. Gadolinium-enhanced magnetic resonance imaging of the brain revealed a 2.0-cm multilobular, partially cystic, peripheral-enhancing mass in the posterior left temporal-parietal region with significant vasogenic edema and localized mass effect. A detailed laboratory investigation revealed that this patient was immunocompetent. An awake left posterior temporal-parietal craniotomy with cortical motor and speech mapping, using frameless stereotactic image guidance and intraoperative real-time ultrasound, was performed. Frozen section was consistent with cerebral abscess and methenamine silver staining revealed many beaded, thin-branching gram-positive bacilli. Colonies suspicious for Nocardia sp were seen within 2 days, and PCR followed by pyrosequencing (PS) identified Nocardia farcinica.


CONCLUSIONS
We report a nocardial cerebral abscess mimicking a metastatic brain tumor, and we demonstrate that PS technology can be used for the accurate and rapid identification of N farcinica isolated from a brain abscess -- facilitating a rapid diagnosis and successful, durable treatment.
Iannotti
Christopher A
CA
Brain Tumor Institute and the Department of Neurological Surgery, Cleveland Clinic, Cleveland, OH 44195, USA. iannotc@ccf.org
Hall
Geraldine S
GS
Procop
Gary W
GW
Tuohy
Marion J
MJ
Staugaitis
Susan M
SM
Weil
Robert J
RJ
D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000627:therapeutic use; D001921:Brain / Q000382:microbiology / Q000473:pathology / Q000601:surgery; D001922:Brain Abscess / Q000175:diagnosis* / Q000382:microbiology* / Q000601:surgery; D001932:Brain Neoplasms / Q000175:diagnosis / Q000556:secondary; D002277:Carcinoma / Q000175:diagnosis / Q000556:secondary; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D003937:Diagnosis, Differential; D003943:Diagnostic Techniques, Neurological; D004342:Drug Hypersensitivity; D004827:Epilepsy / Q000139:chemically induced; D005838:Genotype; D006801:Humans; D007121:Immunocompetence; D008175:Lung Neoplasms / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008967:Molecular Biology / Q000379:methods; D019635:Neurosurgical Procedures; D009615:Nocardia / Q000235:genetics*; D009617:Nocardia Infections / Q000150:complications* / Q000175:diagnosis* / Q000188:drug therapy; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial