Ring-Enhancing Brain Lesion in a Man with Acquired Immunodeficiency Syndrome

A 46-year-old Hispanic man with acquired immunodeficiency syndrome (AIDS) and a history of cryptococcal meningitis presented with new-onset simple partial seizures. He had noticed 2 weeks of progressive weakness and numbness of his right arm for which his highly active antiretroviral therapy (HAART) had been discontinued. He denied any fever, weight loss, changes in his vision, or headache. On examination, the patient had oral thrush, was unable to lift his right arm against gravity, had some weakness in his right leg, and sensation was decreased on the right side of his body. Head computed tomography (CT) scan with contrast and a brain magnetic resonance image (MRI) showed a ring-enhancing lesion in the left posterior frontal lobe with surrounding edema, without midline shift (Figure 1, Figure 2). Cerebral spinal fluid (CSF) analysis was within normal limits. No growth of bacteria, mycobacteria, or fungus was noted. Tests for Epstein Barr virus, herpes simplex virus, cytomegalovirus DNA, and the cryptococcal antigen were negative. The patient’s CD4 count was 182 cells/mm³ and the viral load was <400 copies/mm³. He was found to have microcytic anemia with a hemoglobin of 8.4. His urinalysis revealed 4-10 red blood cells/hpf. Toxoplasma gondii serology returned positive for immunoglobulin G and negative for immunoglobulin M. Based on the patient’s head CT findings, he was started on treatment for central nervous system toxoplasmosis and a bacterial brain abscess. Because he showed no clinical improvement and a repeat head CT showed an increase in the size of the lesion, the patient underwent a brain biopsy.