 There is a lesion in the left frontal lobe measuring approximately 12 x 17 mm in transaxial dimension and 19 mm in cc dimension. The lesion is primarily hypointense on T1, hyperintense on T2, demonstrating signal nulling with FLAIR technique. Internally there are small punctate to linear foci of differing signal characteristics, specifically demonstrating T2 hypointensity, T1 hyperintensity, without susceptibility abnormality. There is no associated contrast enhancement or restricted diffusion. The lesion extends to adjacent subcortical white matter, however without involving overlying cortices. Additionally, there is no associated mass effect.Ventricular sizes are normal. There is no midline shift. There are no diffusion abnormalities elsewhere to suggest the presence of acute ischemia. Myelination appears normal for a term infant. Expected vascular flow voids are demonstrated. The mastoid air cells and middle ear cavities are clear.
Complex, unusual appearing, nonenhancing lesion of the left frontal lobe as described in detail above. The constellation of features are most suggestive of a tumefactive perivascular space. However, the internal punctate to linear foci are unusual for this diagnosis. Thus, the differential diagnosis also includes dysembryoplastic neuroepithelial tumor (DNET). Recommendations are made to obtain follow-up imaging in 3 months with contrast, or sooner if patient symptoms related to the CNS change.