Two for the Price of One: A Case of Methicillin-Resistant Staphylococcus aureus (MRSA) Brain Abscess With Atypical
Frailyn J Nunez1, Shorabh Sharma1, Michelle Dahdouh2
1Internal Medicine, SBH (St. Barnabas Hospital) Health System, Bronx, USA.
Abstract:
Multiple etiologies can coexist and trigger CNS symptoms in individuals infected with HIV. This article reviews a case of a cerebellar mass in an HIV patient who, on biopsy, grew methicillin-resistant Staphylococcus aureus (MRSA) and by pathology, showed an atypical lymphoplasmacytic infiltrate concerning a clonal lymphoproliferative process, which may be a precursor of CNS lymphoma. The patient, a 36-year-old male with multiple comorbidities including HIV Infection, presented to the hospital for evaluation of a one-week course of headache and photophobia. Remarkable physical examination findings included dilated pupils and anisocoria. Initial CT brain imaging revealed vasogenic edema seen throughout the left cerebellar hemisphere provoking mass effect on the fourth ventricle and pontocerebellar cistern resulting in mild hydrocephalus, new findings compared to prior. MRI brain displayed a T1 isointense, T2 hypointense ring-enhancing lesion in the left cerebellar hemisphere, with restricted diffusion, and surrounding vasogenic edema resulting in mass effect over the fourth ventricle, left cerebellar peduncle, and pontocerebellar cistern causing mild hydrocephalus. The patient underwent left suboccipital craniotomy with evacuation of the cerebellar lesion by neurosurgery. Tissue cultures grew MRSA. Pathology was sent to New York-Presbyterian Columbia University Irving Medical Center due to the presence of atypical lymphoplasmacytic infiltrates. The final diagnosis was polyclonal B-cell population in the sample; however, prominent peaks were also seen above the polyclonal background, possibly representing a clonal proliferation. Therefore, the lymphoplasmacytic infiltrates remained atypical and the possibility of the underlying clonal lymphoproliferative process could not be entirely ruled out.
Insights
A cerebellar mass in an HIV patient was caused by methicillin-resistant Staphylococcus aureus (MRSA) infection. Pathology revealed atypical lymphoplasmacytic infiltrates, suggesting a potential precursor to central nervous system (CNS) lymphoma.
Area of Science:
- Neurology
- Infectious Diseases
- Oncology
Background:
- Human immunodeficiency virus (HIV) infection can present with diverse central nervous system (CNS) symptoms due to multiple coexisting etiologies.
- Cerebellar masses in HIV patients require thorough investigation to differentiate infectious from neoplastic processes.
Observation:
- A 36-year-old male with HIV presented with headache and photophobia, exhibiting dilated pupils and anisocoria.
- Brain imaging revealed a left cerebellar hemisphere mass with vasogenic edema, mass effect, and mild hydrocephalus.
- Surgical evacuation of the cerebellar lesion yielded methicillin-resistant Staphylococcus aureus (MRSA) on tissue culture.
Findings:
- Pathological examination of the cerebellar lesion showed atypical lymphoplasmacytic infiltrates.
- While the predominant finding was a polyclonal B-cell population, atypical peaks suggested a possible clonal lymphoproliferative process.
- The coexistence of MRSA infection and atypical lymphoplasmacytic infiltrates raised concerns for a precursor to CNS lymphoma.
Implications:
- This case highlights the complex interplay of infectious and lymphoproliferative processes in the CNS of HIV-infected individuals.
- Accurate diagnosis is crucial, as differentiating MRSA abscess from CNS lymphoma or other infiltrative processes can be challenging.
- Further investigation into clonal lymphoproliferative processes as a potential complication or co-morbidity in HIV patients with CNS lesions is warranted.
