Dural tail sign

The dural tail sign (also known as dural thickening, the flare sign, or the meningeal sign) is a radiological finding observed in magnetic resonance imaging (MRI) studies of the brain that refers to a thickening of the dura mater immediately adjacent to a mass lesion, such as a brain tumor.^[1] Initially, the dural tail sign was thought to be pathognomonic of meningioma, a slow-growing tumor that arises from the meninges.^[1] However, subsequent studies have shown that it can also be observed in various intra- and extra-cranial pathologies and in spinal lesions.^[1] It is not a completely sensitive finding, as it is seen in only 60-72% of cases.^[2] It is not completely specific either, as it has been described associated with lesions like neuromas, chloromas, pituitary diseases, granulomatous disorders, cerebral Erdheim-Chester disease, lymphomas, metastasis, hemangiopericytomas, schwannomas, and gliomas such as glioblastoma multiforme (GBM).^[2][3] The final diagnosis should be further established through cerebrospinal fluid analysis or histopathological examination following a biopsy.^[3]

The dural tail sign was first described in 1989 by Wilms et al..^[1][4] Histopathological correlation from different studies has at times revealed tumor infiltration into the dura mater, however, in most instances, it signifies a hypervascular, non-neoplastic response.^[3]

One study showed that including the dural tail in the stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) volumes for meningioma treatment did not seem to impact recurrence.^[5]