AIDS-Related Central Nervous System Toxoplasmosis With Increased 18F-Fluoroethyl-L-Tyrosine Amino Acid PET Uptake Due to LAT1/2 Expression of Inflammatory Cells.

Abstract

We report the case of a 40-year-old woman with a progressive right-sided hemiparesis. Standard MRI revealed a contrast-enhancing brain lesion within the left basal ganglia. Ffluoroethyl-L-tyrosine (F-FET) PET showed a distinct tracer uptake (lesion-to-brain ratio [LBR]: LBRmax = 2.03, LBRmean = 1.68) with a significant larger metabolic lesion volume than contrast-enhancement in MRI, indicating cerebral glioma. Surprisingly, histopathologic analysis demonstrated central nervous system toxoplasmosis with pronounced inflammatory reaction (reactive astrogliosis, microglia activation, macrophage, and T-lymphocyte infiltration), which was associated with strong LAT1/LAT2/CD98 expression. In conclusion, inflammatory brain lesions, such as cerebral toxoplasmosis, represent a potential pitfall of F-FET PET mimicking a brain tumor.

• Authors: Markus Hutterer, Elisabeth Bumes, Markus J Riemenschneider, Jirka Grosse, Dirk Hellwig, Norbert Galldiks, Karl-Josef Langen, Peter Hau
• Journal: Clinical nuclear medicine (Clin Nucl Med) Vol. 42 Issue 12 Pg. e506-e508 (Dec 2017) ISSN: 1536-0229 [Electronic] United States
• PMID: 29076908 (Publication Type: Case Reports, Journal Article)

Chemical References

• Adaptor Proteins, Signal Transducing
• LAT2 protein, human
• Large Neutral Amino Acid-Transporter 1
• (18F)fluoroethyltyrosine
• Tyrosine

Topics

• Acquired Immunodeficiency Syndrome (complications)
• Adaptor Proteins, Signal Transducing (metabolism)
• Adult
• Biological Transport
• Brain Neoplasms (diagnostic imaging)
• Diagnosis, Differential
• Female
• Gene Expression Regulation
• Humans
• Inflammation (pathology)
• Large Neutral Amino Acid-Transporter 1 (metabolism)
• Positron-Emission Tomography
• Toxoplasmosis, Cerebral (complications, diagnostic imaging, metabolism)
• Tyrosine (analogs & derivatives, metabolism)