Tumelkans Roberts, Eraslan Cenk, Balodis Arturs
Faculty of Medicine, Riga Stradins University, LV-1007 Riga, Latvia.
Radiology Department, Ege University, 35040 Bornova, Turkey.
Diagnostics (Basel). 2025 Jun 11;15(12):1486. doi: 10.3390/diagnostics15121486.
A newly recognized fourth type of perivascular space has recently been described in the radiological literature. Despite its growing relevance, many radiologists are still unfamiliar with its imaging characteristics, often leading to misinterpretation as cystic neoplasms. Due to its potential for diagnostic confusion, further studies are necessary-particularly those incorporating high-quality imaging examples across various presentations-to facilitate accurate recognition and classification. Perivascular spaces (PVSs) of the brain are cystic, fluid-filled structures formed by the pia mater and located alongside cerebral blood vessels, particularly penetrating arterioles, venules, and capillaries. Under normal conditions, these spaces are small (typically <2 mm in diameter), but in rare instances, they may become markedly enlarged (>15 mm), exerting a mass effect on adjacent brain tissue. This newly identified fourth type of PVS is found in association with the M2 and M3 segments of the middle cerebral artery, typically within the anterior temporal lobe white matter. It may mimic low-grade cystic tumors on imaging due to its size and frequent presence of surrounding perifocal edema. We present two adult male patients with this rare PVS variant. The first patient, a 63-year-old, had a brain magnetic resonance imaging scan (MRI) that revealed a cystic lesion in the white matter of the right temporal lobe anterior pole, near the middle cerebral artery M2 segment, with perifocal vasogenic edema. The second patient, a 67-year-old, had a brain MRI that showed a cystic lesion in the white matter and subcortical region of the right temporal lobe anterior pole, with minimal surrounding gliosis or minimal edema. The cystic lesions in both patients remained unchanged over time on follow-up MRI. These cases illustrate the radiological complexity of this under-recognized entity and emphasize the importance of differential diagnosis to avoid unnecessary intervention.
放射学文献中最近描述了一种新发现的第四类血管周围间隙。尽管其相关性日益增加，但许多放射科医生仍不熟悉其影像学特征，常常导致误诊为囊性肿瘤。由于其可能造成诊断混淆，因此有必要进行进一步研究，尤其是那些纳入各种表现形式的高质量影像学实例的研究，以促进准确识别和分类。脑内血管周围间隙（PVSs）是由软脑膜形成的囊性、充满液体的结构，位于脑血 管旁，特别是穿通小动脉、小静脉和毛细血管旁。在正常情况下，这些间隙较小（直径通常<2mm），但在罕见情况下，它们可能会显著增大（>15mm），对相邻脑组织产生占位效应。这种新发现的第四类PVS与大脑中动脉的M2和M3段相关，通常位于颞叶前部白质内。由于其大小以及周围常出现灶周水肿，在影像学上可能类似低度囊性肿瘤。我们报告了两名患有这种罕见PVS变异型的成年男性患者。第一名患者为63岁男性，脑部磁共振成像（MRI）扫描显示右侧颞叶前极白质靠近大脑中动脉M2段处有一个囊性病变，并伴有灶周血管源性水肿。第二名患者为67岁男性，脑部MRI显示右侧颞叶前极白质和皮质下区域有一个囊性病变，周围仅有轻微胶质增生或轻微水肿。随访MRI显示，两名患者的囊性病变随时间推移均无变化。这些病例说明了这种未被充分认识的实体的放射学复杂性，并强调了鉴别诊断以避免不必要干预的重要性。
