Two Cases of Idiopathic Middle Meningeal Arteriovenous Fistula Initially Diagnosed by Magnetic Resonance Angiography.

Reports of middle meningeal arteriovenous fistula (MMAVF) are relatively rare, and reports of idiopathic MMAVF are extremely rare. In the past, diagnoses of MMAVF have been confirmed by cerebral angiography, but magnetic resonance angiography (MRA) resolution is improving. Here, we report two cases of idiopathic MMAVF that were diagnosed by unreconstructed time-of-flight MRA (MRA-TOF) and successfully treated by trans-arterial embolisation with endovascular treatment. Both patients suffered from pulsatile tinnitus, and MRI was performed. Two dilated vessels were revealed in the middle temporal fossa by unreconstructed MRA-TOF imaging. These dilated vessels were thought to be the middle meningeal artery and middle meningeal vein; therefore, we diagnosed both patients with MMAVF. Following angiography, both patients had coil embolisation with endovascular treatment, and their conditions improved. In cases of idiopathic MMAVF without a history of trauma, brain surgery, or endovascular surgery, unreconstructed MRA-TOF may be useful as a primary diagnostic tool, and endovascular treatment before bleeding may produce better outcomes.

Dural Arteriovenous Fistula-Derived Parkinsonism Symptoms: A Case Report with Literature Review.

Objective: Parkinsonism caused by dural arteriovenous fistula (DAVF) is very rare, however, it is reversible by endovascular treatment. We herein report a case of parkinsonism caused by DAVF with review of previous literature. Case Presentation: An 87-year-old woman with parkinsonism and dementia was admitted to our hospital with disturbance of consciousness and aggravated parkinsonism symptoms. Plain CT revealed low-density areas in the brainstem and left cerebellar peduncle. Magnetic resonance images revealed hyperintense lesions on FLAIR, which had elevated apparent diffusion coefficient (ADC) values, in the same lesion of plain CT. However, no edematous change was detected. CT angiograms revealed obstruction of the left transverse and sigmoid sinuses. Dilations of the left superior petrosal sinus, left petrosal vein, and pontine veins were also noted. A low-density area on plain CT had a contrast effect. Cerebral angiography revealed a DAVF involving the left transverse sinus and fed by the left occipital and left middle meningeal arteries. Transarterial embolization (TAE) with Onyx obliterated the DAVF, and parkinsonism symptoms gradually improved. We reviewed 21 DAVF-derived parkinsonism cases, most of which were treated by TAE. Recent cases were treated with Onyx. In many cases, parkinsonism improved after endovascular treatment. Conclusion: DAVF-derived parkinsonism is rare but treatable by endovascular therapy. DAVF should be one of the differential diagnosis of the parkinsonisms.

Primary and Recurrent Growing Teratoma Syndrome in Central Nervous System Nongerminomatous Germ Cell Tumors: Case Series and Review of the Literature.

BACKGROUND: The term "growing teratoma syndrome (GTS)" has been used as follows: patients with germ cell tumor (GCT) who present with enlarging original/metastatic masses during or after appropriate systemic chemotherapy despite normalized serum markers. In other words, the definition of the term GTS is not fully established. We analyzed and reviewed our case series regarding GTS that developed after the treatment of central nervous system (CNS) nongerminoatous germ cell tumors (NGGCTs). METHODS: Our institutional review board approved this retrospective study. Between 2003 and 2018, we treated 16 patients (16 males; age ranging from 5.4 to 51.9 years, median 13.8) with CNS-NGGCT at our institution. We reviewed those patients and also reviewed the literature about GTS of CNS. We defined primary GTS (p-GTS) as the enlargement of cyst size and/or solid tumor occurred during treatment in the absence of marker elevation, and recurrent GTS (r-GTS) as the enlargement of teratoma after complete response of initial tumors. RESULTS: Among 16 patients with CNS-NGGCT, we surgically confirmed mature/immature teratoma components in 15 patients. Two patients underwent surgical removal of tumor before neoadjuvant therapy, and among the rest 14 patients, 6 developed p-GTS, and 2 patients underwent salvage surgery during chemo-/chemoradiotherapy. Those with histologic diagnosis of immature teratoma during salvage surgery had a shorter interval from the initiation of chemoradiotherapy compared with mature teratoma (P < 0.05). One patient developed r-GTS. In the literature review, most of the p-GTS consisted of enlargement with the multicystic component. Histologic diagnosis of immature teratoma during salvage surgery was observed in earlier stages of chemoradiotherapy (P < 0.05, log-rank test). Previous history of p-GTS might be a risk factor of r-GTS. CONCLUSIONS: The incidence of p-GTS, enlargement of the cystic component during treatment, is not rare. Physicians need to be aware of this important phenomenon.

Proton Magnetic Resonance Spectroscopy Detection of High Lipid Levels and Low Apparent Diffusion Coefficient Is Characteristic of Germinomas.

BACKGROUND: The differentiation of germinoma from other tumors by conventional magnetic resonance imaging (MRI) can be very difficult. The purpose of our study was to determine whether diffusion-weighted imaging (DWI) and single-voxel proton magnetic resonance spectroscopy (1H-MRS) could provide additional useful information for a definitive diagnosis of germinomas. METHODS: Our hospital's Institutional Review Board approved this retrospective study. We reviewed imaging studies of 26 patients with histologically confirmed germinomas who were treated at our hospital between 2003 and 2016. We also studied 25 patients with pineal tumors, which included 14 nongerminomatous germ cell tumors (NGGCTs), 9 pineal parenchymal tumors (PPTs; including 3 pineocytomas, 4 PPTs of intermediate differentiation [PPTID], and 2 pineoblastomas) and 2 meningiomas. Patients underwent conventional MRI and advanced MRI, including DWI and/or 1H-MRS. RESULTS: The germinoma group comprised 24 males and 2 females, ranging in age from 9.1 to 37.7 years (average, 17.5 years; median, 14.6 years). The NGGCT group was all male, ranging in age from 5.4 to 51.9 years (mean, 20.1 years; median, 14.1 years). In the PPT group, patient age ranged from 4.5 to 64.7 years (mean, 29.9 years; median, 30.7 years). High lipid peaks detected on 1H-MRS were observed in 16 of 16 examined germinomas. In contrast, in the pineocytomas, PPTID, pineoblastomas, and meningiomas, lipid peaks were small or absent in 10 of 10 examined tumors. In the NGGCT group, high lipid peaks on 1H-MRS were observed in 11 of 12 examined tumors; however, no tumors showed high intensity on DWI, with all low to high mixed intensity. ADC was statistically lower in the germinoma group compared with the NGGCT group (P = 0.0002). CONCLUSIONS: Lower ADC values and high lipid peaks detected on 1H-MRS are characteristics of germinomas.