Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia
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We report a 58-year-old man who developed hyptertrophic olivary degeneration (HOD) after haemorrhage of a cavernous malformation in the pons. Lesions of the triangle of Guillain and Mollaret (the dentatorubro-olivary pathway) may lead to HOD, a secondary transsynaptic degeneration of the inferior olivary nucleus. HOD is considered unique because the degenerating olive initially becomes hypertrophic rather than atrophic. ⋯ The imaging features of HOD evolve through characteristic phases. The clue to the diagnosis of HOD is recognition of the distinct imaging stages and identification of a remote primary lesion in the triangle of Guillain and Mollaret. Familiarity with the classic imaging findings of this rare phenomenon is necessary in order to avoid misdiagnosis and prevent unnecessary intervention.
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Case Reports
Operative results of keyhole supracerebellar-infratentorial approach to the pineal region.
The supracerebellar-infratentorial approach to the pineal region is typically accomplished with a craniotomy that extends to at least the rim of the foramen magnum. Minimally invasive techniques that limit the inferior extent of the craniotomy have been described for this approach but, to our knowledge, no operative results have been published demonstrating the feasibility and safety of such techniques. We present a series of patients who underwent surgical resection of pineal region lesions using the minimally invasive method at our institution. ⋯ No neurological or systemic complications were seen in the perioperative and early follow-up periods. In this feasibility study, we demonstrate that it is not necessary to extend a craniotomy inferiorly to the rim of the foramen magnum in order to gain access to the pineal region via relaxation of the cerebellum. The same surgical goals can be safely accomplished with a smaller craniotomy.
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Case Reports
Extreme volume expansion of a vestibular schwannoma due to intratumoral hemorrhage after gamma knife radiosurgery.
A 48-year-old man with right hemi-facial palsy and cerebellar ataxia was referred to our hospital. Three years and 10 months earlier he had undergone gamma knife radiosurgery (GKRS) at the referring hospital for an 18 mm right vestibular schwannoma. Slight tumor enlargement had been observed on MRI performed at the referring hospital 3 years after the GKRS. ⋯ Histopathological examination revealed massive intratumoral hemorrhage within a typical vestibular schwannoma with no malignancy. The complication of intratumoral hemorrhage is very rare and the utility of stereotactic radiation surgery/therapy, including GKRS, for vestibular schwannoma is well known. However, we must emphasize that careful follow-up is still required, even after several years.
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We reviewed clinical, imaging and histopathology details of 297 patients who underwent surgery for pituitary adenomas, with an equal distribution of functional and non-functioning tumors, to examine clinicopathological correlates of extrasellar growth. Knosp grades of 3 and 4 on MRI defined cavernous sinus invasion, Hardy grades of C and D defined significant suprasellar/subfrontal extension, and intraoperative evidence of tumor eroding through the clivus or sellar floor defined infrasellar invasion. Disease status at follow-up was known in 246 patients overall, including 35 patients who were evaluated for progression of residual disease on serial imaging. ⋯ Individual patterns of extrasellar growth in pituitary adenomas are associated with unique clinical and immunohistochemical profiles. Younger patients with elevated MIB-1 values are probably at high risk for early recurrence of non-functioning tumors. Definitions of atypia must be standardized before more robust assumptions about tumor biology can be established.
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We evaluate if the relationship between optical coherence tomography (OCT) of the retinal nerve fibre layer (RNFL) and visual outcome continued over long-term visual recovery in 107 patients undergoing pituitary decompression. Recently, it has been recognized that OCT of the RNFL has prognostic value in predicting visual outcomes after surgery for chiasmal compression caused by pituitary tumours. Patients were followed up at three time points: pre-operative (visit 1), 6-10 weeks post-operative (visit 2) and 9-15 months follow-up (visit 3). ⋯ Our results indicate that long-term visual recovery after surgical decompression of pituitary lesions is predicted by pre-operative OCT RNFL. Patients with normal RNFL thickness show an increased propensity for visual recovery. This effect continues after long-term follow-up, however, most visual recovery occurs within the first 6-10 weeks.