An algorithmic approach to intracranial mass lesions in HIV/AIDS.

We developed a diagnostic and therapeutic algorithm for intracranial mass lesions in patients with HIV/AIDS that obviates the need for neurosurgical intervention. The approach is based upon CD4(+) lymphocyte count, serum toxoplasma immunoglobulin G (IgG) serology, chest X-ray, routine lumbar puncture studies, cerebrospinal fluid (CSF) cytology, CSF adenosine deaminase or Mycobacterium tuberculosis polymerase chain reaction testing, single positron emission-computed tomography (SPECT) scanning for intracranial enhancing lesions, and limited therapeutic trials. Over a 12-month period involving 26 patients, we found that the algorithm correctly identified the aetiology of focal intracranial lesions in all 23 evaluable patients. Costs for SPECT scanning for the entire study cohort were more than offset by the savings achieved by reduced hospital stays for the four patients with lymphoma alone. An algorithmic approach can accurately identify the cause(s) of central nervous system (CNS) mass lesions in HIV-infected patients, and SPECT scanning can replace stereotactic brain biopsy in most cases where opportunistic malignancy is suspected.