ABSTRACT
Purpose Trochlear nerve schwannomas are rare tumors. So far, only 121 cases have been published. We present four new cases, discuss the imaging characteristics and summarize all previously published cases through a systematic review.Methods Four cases, all treated in AZ Sint-Jan Hospital Brugge-Oostende (Belgium), were collected, including their demographic, clinical and radiological data. All MR imaging was performed with the three-dimensional fluid-attenuated inversion recovery (3D-FLAIR), turbo spin echo T1 high-resolution (TSE T1 HR), three-dimensional balanced fast-field echo (3D b-FFE) and three-dimensional T1 black blood (3D T1 black blood) sequence. We compared our findings with the present literature through a systematic literature review in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines.Results Screening with routine unenhanced 3D-FLAIR imaging could identify all schwannomas as hyperintense lesions on the course of the trochlear nerve. The use of 3D T1 black blood sequences was superior in depicting the lesions, while high-resolution 3D b-FFE images enabled us to visualize the anatomic boundaries of the lesions in detail. Most trochlear schwannomas are located in the ambient cistern, at or just below the free edge of the tentorium.Conclusion The majority of trochlear nerve schwannomas are located cisternal and display variable enhancement on contrast administration. 3D-FLAIR imaging is superior in detecting these lesions. Comparison with data collected from previous cases demonstrates the importance of early diagnosis and treatment. Generally, patients with trochlear nerve schwannomas have a good prognosis.
ABSTRACT
OBJECTIVE: To illustrate the possibility of spontaneous involution of a pineal cyst, justifying an initial observation strategy in patients without evident mass effect. BACKGROUND: Pineal cysts are frequent radiological findings, with a reported overall prevalence from 0.6% to 40%. Historically, surgery has been reserved for patients with symptoms attributable to a mass effect of the cyst. Despite the high prevalence of pineal cysts, the clinical approach to patients with non-specific symptoms remains controversial. METHODS: We report on the spontaneous involution of a large pineal cyst in a 26-year-old female who presented in our outpatient clinic with transient symptoms of headache and nausea. PubMed and Web of Science databases were scrutinized using a predefined search strategy in accordance with the Population, Intervention, Comparison and Outcome (PICO) set-up using "pineal cyst" and "surgery" as search terms. Only peer-reviewed publications were considered eligible. Titles and abstracts of 1513 manuscripts were screened for relevance. After excluding 1420 publications evaluating non-relevant pathology, the eligibility of the remaining 93 full-text records was further assessed and included if they reported patients with pineal cysts presenting with intractable symptoms without hydrocephalus or Parinaud syndrome, and if they documented on their symptomatology and clinical management. CONCLUSION: Recent case series and reviews report favorable results of surgery in patients with pineal cysts but also a potentially high complication rate. However, the evidence offered by these reports is limited and a placebo effect cannot be ruled out. Therefore, surgery cannot be unequivocally advocated in these patients. Instead, an initial surveillance strategy is advocated. We concur with a previously propounded surveillance strategy of a single follow-up magnetic resonance imaging at 12 months. This case report demonstrates the importance of an initial observation strategy since pineal cysts may also show a spontaneous involution.
