Subcortical Cystic Lesions within the Anterior Superior Temporal Gyrus: A Newly Recognized Characteristic Location for Dilated Perivascular Spaces

Abstract

SUMMARY: Cystic parenchymal lesions may pose an important diagnostic challenge, particularly when encountered in unexpected locations. Dilated perivascular spaces, which may mimic cystic neoplasms, are known to occur in the inferior basal ganglia and mesencephalothalamic regions; a focal preference within the subcortical white matter has not been reported. This series describes 15 cases of patients with cystic lesions within the subcortical white matter of the anterior superior temporal lobe, which followed a CSF signal; were located adjacent to a subarachnoid space; demonstrated variable surrounding signal change; and, in those that were followed up, showed stability. Pathology study results obtained in 1 patient demonstrated chronic gliosis surrounding innumerable dilated perivascular spaces. These findings suggest that dilated perivascular spaces may exhibit a regional preference for the subcortical white matter of the anterior superior temporal lobe. Other features-lack of clinical symptoms, proximity to the subarachnoid space, identification of an adjacent vessel, and stability with time-may help in confidently making the prospective diagnosis of a dilated perivascular space, thereby preventing unnecessary invasive management. ABBREVIATION: SAS ϭ subarachnoid space

Multinodular and Vacuolating Neuronal Tumor of the Cerebrum: A New “Leave Me Alone” Lesion with a Characteristic Imaging Pattern

“…Prominent perivascular spaces that are below the resolution of 1.5 or 3T MR imaging may not suppress on FLAIR, but this pattern is usually described as an abnormal white matter signal surrounding other typical enlarged perivascular spaces, particularly in the anterior temporal region. 8 While the most common clinical manifestation was an episode of seizure in the neuropathology literature, 1,[3][4][5][6] in this series, possible seizure was only observed in a few patients (19%) and the remainder presented with nonspecific, nonfocal clinical manifestations. Most MVNTs are usually an incidental finding on imaging studies and may be more common than other neuronal and mixed glioneuronal tumors.…”

Spontaneous Regression and Recurrence of a Tumefactive Perivascular Space

“…Dilated perivascular spaces have been described to occur in three characteristic locations: along the lenticulostriate arteries entering the basal ganglia through the anterior perforated substance, along the paths of the perforating medullary arteries as they enter the cortical gray matter over the high convexities extending into the white matter and in the midbrain (1). The temporal subcortical region is a recently described location of tumefactive perivascular space 8,9 . The precise mechanism leading to dilatation of perivascular spaces is not clear.…”

Neuroimaging of Dilated Perivascular Spaces: From Benign and Pathologic Causes to Mimics

“…A distinct, fourth category of dilated PVSs has been more recently characterized in the subcortical white matter of the anterior superior temporal lobe. These dilated PVSs often have increased perilesional FLAIR signal, which represents gliosis, and may be mistaken for a cystic neoplasm (Figs and ) . Dilated anterior temporal PVSs can be distinguished from more sinister pathologies by the a lack of clinical symptoms, proximity to subarachnoid space, identification of adjacent vessels, and stability over time with follow‐up imaging …”

“…These dilated PVSs often have increased perilesional FLAIR signal, which represents gliosis, and may be mistaken for a cystic neoplasm (Figs 5 and 6). 11,12 Dilated anterior temporal PVSs can be distinguished from more sinister pathologies by the a lack of clinical symptoms, proximity to subarachnoid space, identification of adjacent vessels, and stability over time with follow-up imaging. 11 Although there is no clear understanding of how PVSs become dilated, there are multiple theories including perivascular myelin loss, fibrosis/obstruction of lymphatic drainage pathways, alterations of arterial wall permeability or ex-vacuo dilation secondary to brain atrophy.…”