Considering that this lesion has been stable for the past four years since its first recognition, what is the most likely diagnosis?
The lesion almost certainly represents an anterior temporal lobe perivascular space.
What is a considerable differential diagnosis for this case?
A DNET remains a possibility but is thought much less likely.
The small and well-defined juxtacortical cystic lesion is again demonstrated in the anterior right temporal lobe, unchanges since 2013, and showing minimal surrounding T2/FLAIR hyperintensity. The cyst follows CSF signal in all sequences, and there is no associated enhancement and no elevated relative cerebral blood volume (rCBV) on perfusion. MR spectroscopy is unremarkable.
T2/FLAIR hyperintensities foci are again demonstrated scattered through the supratentorial white matter, in a non-specific pattern, most probably related with chronic small vessel ischemic disease.
The remainder of the exam is unremarkable.
Conclusion: Stable appearance of the right temporal lobe small cystic lesion for four years almost certainly representing an anterior temporal lobe perivascular space, which unlike perivascular spaces elsewhere often have some surrounding flair signal abnormality [1-2]. A DNET remains a possibility but is thought much less likely.