"Missing-piece" sign with dural arteriovenous fistula at craniocervical junction: A case report.

OBJECTIVES: Spinal dural arteriovenous fistula (sDAVF) is a rare and often underdiagnosed spinal disease. Early diagnosis is required because the deficits are reversible and delays in treatment cause permanent morbidity. Although the abnormal vascular flow void is a critical radiographic feature of sDAVF, they are not always present. A characteristic enhancement pattern of sDAVF has been recently reported as the "missing-piece" sign which can lead to the early and correct diagnosis. METHODS: We presented imaging findings, treatment decisions, and the outcome of a rare case of sDAVF, in which the "missing-piece" sign appeared atypical. RESULTS: A 60-year-old woman developed numbness and weakness in her extremities. Spinal MRI revealed longitudinal hyperintensity in the T2-weighted image, extending from the thoracic level to medulla oblongata. At first, myelopathy with inflammation or tumor was suspected because of the lack of flow voids and vascular abnormalities in CT-angiography and MR-DSA. However, we administered intravenous methylprednisolone and her symptom got worse with the appearance of the "missing-piece" sign. Then, we successfully diagnosed sDAVF by angiography. The "missing-piece" sign was considered to derive from inconsistency of the intrinsic venous system of spinal cord, with the abrupt segments without enhancement. The same etiology was considered in our case. CONCLUSIONS: Detecting the "missing-piece" sign can lead to the correct diagnosis of sDAVF, even if the sign appeared atypical.

Repeated Intravenous Methylprednisolone May Prevent Deterioration of Hypertrophic Pachymeningitis in Rosai-Dorfman Disease.

Rosai-Dorfman disease (RDD) is a rare form of non-Langerhans cell histiocytosis. Although 20% of patients with RDD have spontaneous remission, some cases with central nervous system (CNS) involvement require surgery or systemic treatment. We encountered a case of RDD in which hypertrophic pachymeningitis was diffuse, eliminating the need for surgical intervention. A 72-year-old Japanese man was diagnosed with RDD based on pathological lymph node findings. Repeated intravenous methylprednisolone (IVMP) administration resolved and stabilized the hypertrophic pachymeningitis without any sequelae. If surgery or anticancer medications are contraindicated, repeated IVMP may be a good therapeutic option for CNS-associated RDD.