Rosette-forming Glioneuronal Tumour of the Fourth Ventricle with Previous Intratumoural Haemorrhage: Case Report and Review of the Literature

YM LI WQ LI Y PAN YC LU NY LONG XF TAO HY YU - >> Version of Record - May 1, 2009 What is This? Downloaded from imr.sagepub.com by guest on October 16, 2014 The case is reported of a rosette-forming glioneuronal tumour of the fourth ventricle (RGTFV) in a 27-year-old male. Symptoms included headache, severe vomiting and clumsy walking that had progressively worsened over 14 days. Computed tomography and magnetic resonance imaging indicated a 3.0 2.5 2.0 cm solid-cystic mass in the fourth ventricle and obstructive hydrocephalus. The tumour showed evidence of previous intra-tumour haemorrhage, with heterogeneous enhancement after contrast administration. Complete excision of the lesion was performed. Signs of previous intra-tumoural haemorrhage were seen intra-operatively. The detailed clinical, radiological and pathological features in this patient are described and compared with existing literature on this type of tumour. Despite benign histological features and a reported favourable post-operative course, there is still limited clinical experience with this type of tumour, however intratumoural haemorrhage may result in morbidity and mortality. This report will help provide better characterization of this entity, improving the diagnosis and potentially reducing mortality in RGTFV. Introduction Several new types of central nervous system (CNS) tumours have been characterized in the past decade. Rosette-forming glioneuronal tumour of the fourth ventricle (RGTFV) is a rare benign neoplasm of the CNS (World Health Organization [WHO] grade I).1 3 Previously this type of tumour was considered to be a cerebellar dysembryoplastic neuroepithelial tumour (DNT),4 occurring mainly in the fourth ventricle area. It was first described in a series of 11 patients by Komori et al.5 RGTFV was adopted as a novel tumour type in the recently published fourth edition of the WHO Classification of Tumours of the Central Downloaded from imr.sagepu9b.c5om8by guest on October 16, 2014 Nervous System.1 3 It occurs in young people5 and has a slight female bias:6 the male-to-female ratio is approximately 1:2.7 It usually presents with a benign clinical history over several weeks to months, or even years in some patients. The most common presenting symptoms include headache, vomiting and ataxia,3,5 8 however intratumoural haemorrhage resulting in morbidity and mortality has been reported.7 Pathologically, RGTFV is composed of two distinct histological components: one with uniform neurocytes forming rosettes and/or perivascular pseudorosettes; the other being astrocytic in nature and resembling pilocytic astrocytoma, a low-grade tumour (WHO grade I)1 3,8 The tumour grows slowly and rarely invades the surrounding brain tissue. It does not spread outside of the ventricle via the cerebrospinal fluid. Usually this tumour does not show mitotic activity and so is not associated with an adverse clinical course.3 Treatment involves resection of the tumour. It has a good prognosis, but may occasionally relapse after surgery.9 This case report describes a patient with RGTFV and reviews the clinical and histological characteristics of this and other published cases. Case report A 27-year-old man presented with severe vomiting, headache and clumsy walking that had progressively worsened over a period of 14 days. There was no significant past medical history of note. On admission, the patient had signs and symptoms of increased intracranial pressure and cerebellar signs with ataxia. Computed tomography and magnetic resonance imaging (MRI) showed a 3.0 2.5 2.0 cm solid cystic mass in the fourth ventricle and obstructive hydrocephalus. The tumour showed evidence of previous intratumoural haemorrhage, with heterogeneous enhancement after contrast administration. Satellite lesions were not seen (Fig. 1). The patient was given a diagnosis of a solid mass in the fourth ventricle, and choroid plexus papilloma with intratumoural haemorrhage. Complete excision of the lesion was performed. Signs of previous intratumoural haemorrhage were seen intra-operatively. The pathological specimen was a grey yellow fragment measuring 4.0 3.0 1.0 cm. Paraffin sections stained with haematoxylin and eosin showed a relatively hypocellular glioneuronal tumour containing a mixture of several different morphological features (Fig. 2). Part of the tumour tissue was composed of glial fibres, mucoid ground substance and elongated bipolar astrocytic cells with mild nuclear pleomorphism and positive for glial fibrillary acidic protein (GFAP). A large number of small vessels were observed, some of which showed hyalinization. Previous haemorrhage was revealed by haemosiderin deposition. Granular eosinophilic bodies with a few Rosenthal fibres were observed. Microcalcification was occasionally seen. In contrast, other areas of the tumour tissue consisted of small uniform neurocytes with little cytoplasm and small spherical nuclei with even nuclear chromatin. These cells were either dispersed in delicate fibrillary sheets or formed into well-defined rosettes around the fibrillary sheets. The cores of the rosettes and the fine fibrillary background were stained with synaptophysin. A few oligodendrocyte-like cells were dispersed in the fibrillary matrix background. Many of the small cells showed positive cytoplasmic immunostaining for S100 protein. A small percentage of cells (1 2%) were positive for the proliferation marker Ki67. Downloaded from imr.sagepu9b.c5om9by guest on October 16, 2014 Discussion Rosette-forming glioneuronal tumour of the described neuronal tumour.1 3 The aqueduct, pineal region, ventricle, a rare, slow-growing cerebellar vermis, midbrain and thalamus tumour of young adulthood, is a newly are frequently involved in addition to the Downloaded from imr.sagepu9b.c6om0by guest on October 16, 2014 fourth ventricle.5 7,9 Preusser et al.10 reported some patients; it commonly presents with a case without involvement of the fourth headache, due to obstructive hydrocephalus, ventricle. The differences between DNT of the and/or ataxia,3,5 8 The dramatic onset of cerebellum10 described:5 in symptoms in the present case was due to there is rosette intra-tumoural haemorrhage leading to a formation by neurocytes and the glial sudden obstruction of the aqueduct. This component of the tumour is usually a possible complication of RGTFV has been pilocytic astrocytoma. reported in one other case and may be In the case presented here the patient was associated with a possible malignant clinical young, which is consistent with reports.5 The patient had symptoms of course.7 Radiologically, presents vomiting headache, isohypointense T1-weighted obstructive hydrocephalus, and hyperintense on T2-weighted MRI images. resulting in clumsy walking. Despite the Calcification may also be seen.5,11 13 The location of this tumour in the cerebellar tumour is relatively well circumscribed, with midline around the fourth ventricle, RG (...truncated)