Unilateral akathisia and choreoathetosis as an unusual presentation of a frontal lobe dermoid cyst.

OBJECTIVE: To consider an unusual presentation of a frontal lobe dermoid cyst. Intracranial masses very rarely present with movement disorders. We describe a highly unusual presentation of an intracranial dermoid with unilateral choreoathetosis, akathisia and facial tics. MATERIAL: A 63-year-old man presented with left-sided akathisia and tardive dyskinesia of his upper limb, attributed to a dermoid cyst in the right frontal lobe. Resection of the cyst led to a complete resolution of his symptoms without neurological deficit. CONCLUSION: Pathogenic mechanisms of such symptoms may include compression and ischaemia of the basal ganglia and other nigrostriatal structures, as well as dysfunction of the supplementary motor area and mesolimbic dopaminergic pathways.

The effect of the revised WHO classification on the incidence of grade II meningioma.

Introduction: A retrospective study over a three-year period at University Hospital of Wales (UHW) of the incidence of atypical cranial grade II meningioma both pre and post 2016 revision of The World Health Organisation (WHO) classification of tumours of the central nervous system.Subjects: All available histology from January 2015 to December 2017 of patients with cranial meningiomas.Method: Institutional online reporting system Welsh Clinical Portal to identify patients and view histology reports.Results: Overall 164 patient histology results were analysed (median age 59, age range 23-82, 74% females). There were 55 patients in 2015: 69.1% grade I, 29.1% grade II and 1.8% grade III. There were 109 patients in 2016/17; 68.8% grade I, 29.4% grade II, 1.8% grade III.Discussion: There is significant variability in the reported incidence of grade II meningioma, likely due to variation in local interpretation of diagnostic criteria. Neuropathologists at our institution have reported brain invasion as grade II prior to 2016. This was due to compelling published evidence that brain invasive meningiomas have recurrence and mortality rates similar to that of grade II meningioma as defined using other criteria. The new 2016 WHO criteria now recognise this specifically. As other institutions adapt to the amended 2016 guidelines we anticipate that there will be a greater consensus in line with our incidence rates of grade II meningioma.

Low-pressure headaches following foramen magnum decompression secondary to absorption of cerebrospinal fluid into the venous system of the diploic space.

INTRODUCTION: We describe a case of a patient who suffered low-pressure headaches secondary to absorption of cerebrospinal fluid into the venous system of the diploic space following a foramen magnum decompression. This case is important as it describes a physiologically plausible but previously undescribed complication of a common surgical intervention. CASE: A nine-year-old boy underwent a foramen magnum decompression for a Chiari malformation (Type I). Five years after his initial decompression, his original symptoms returned and he underwent further decompression with short-term relief of symptoms. He then began to describe low-pressure headaches. Comprehensive investigations revealed a small posterior pseudomeningocoele that had extended into the diploic space at the site of the previous surgery to the occipital bone. It was postulated that the diploic space may be acting as an additional site for reabsorption of his CSF, and as a result of this, he was experiencing consistently low-pressure symptoms. His symptoms have completely resolved following surgical intervention to seal the site of communication with the diploic space. DISCUSSION: We review recent literature that supports this theory through an understanding of the anatomy of the diploic venous system and also its physiological behaviour as demonstrated in recent cadaveric and porcine studies.

Mollaret's triangle: An important neuroanatomical territory for all clinicians.

BACKGROUND: Hypertrophic olivary degeneration is a rare condition caused by damage within the triangle of Guillain and Mollaret. We discuss the anatomical, radiological, and clinical history of this rare condition. CASE DESCRIPTION: A 32-year-old lady presented with sub-acute headache, photophobia, and dizziness. She also described facial tingling and itching over her nose, and a thirty-minute episode of slurred speech. Magnetic resonance imaging revealed a 12.1 × 11 × 7.3 mm lesion arising from the floor of the fourth ventricle [Figure 1]. Postoperative imaging confirmed complete resection of the tumor, but changes consistent with hypertrophic olivary degeneration [Figure 2a and b]. CONCLUSION: An awareness of this complication is of importance to all clinical neuroscience to prevent misdiagnosis with the occurrence of new symptoms.