Purpose - To determine the diagnostic capability of 201T1 single-photon emission computed tomography (SPECT) combined with detection in cerebrospinal fluid (CSF) of EpsteinBarr virus (EBV-DNA for in vivo minimally invasive diagnosis of primary central nervous system lymphoma (PCNSL). Patients and Methods - All HIV-infected patients with focal brain lesions (FBL) observed between June, 1996 and March, 1998 who underwent lumbar puncture and 201T1 SPECT were included. Each CSF sample, besides routine microbiological examinations, was tested by PCR for EBV-DNA. Results - In 13 out of 31 patients, a PCNSL was diagnosed: in all EBV-encoded EBERs expression was found and in 10 EBV-DNA was positive. 201T1 uptake in PCNSL cases ranged from 1.88 to 4.07 (mean 2.77; 95% confidence interval 2.35-3.19) and in non-tumor patients from 0.91 to 3.38 (mean 1.61; 95% confidence interval 1.30-1.94) (p <0.0002). Using as cut-off value the upper limit of the 95% confidence interval of the lesion/background ratio in non-tumor patients, a 201T1 uptake of <1.94 was found in only one PCNSL and 16 non-tumor cases (10 toxoplasmic encephalitis, 3 CMV encephalitis, 1 VZV encephalitis, 1 progressive multifocal leucoencephalopathy, 1 CNS vasculitis). A patient with cryptococcoma and another with tuberculoma had a highly increased 201T1 uptake. EBV-DNA was never detected in non-tumor patients. For the diagnosis of PCNSL hyperactive SPECT lesions showed a 92.3% sensitivity and a 94.1% negative predictive value (NPV), whereas positive EBV-DNA had a 100% specificity and 100% positive predictive value. The absence of increased uptake at SPECT combined with negative EBV-DNA had a NPV of 94.1%. Conclusions - Combined approach with SPECT and EBV-DNA, showed a very high diagnostic accuracy for the discrimination of PCNSL and non-neoplastic FBL in AIDS-patients. Since the likelihood of PCNSL is extremely high in patients with hyperactive lesions and positive EBV-DNA, we think that brain biopsy could be avoided and patients should promptly undergo radiotherapy or multimodal treatment. On the contrary, the extreme improbability of PCNSL in patients showing hypoactive SPECT lesions along with negative EBV-DNA, prompts a first empiric anti-Toxoplasma therapy. In patients with discordant SPECT versus PCR results, brain biopsy, after obtaining negative routinary CSF microbiological investigations, appears to be advisable.
|Number of pages||8|
|Journal||Acta Medica Romana|
|Publication status||Published - 1999|
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