Acta Neurochir (Wien) (2004) 146: 1241–1244 DOI 10.1007/s00701-004-0366-5 Review Article Pleomorphic xanthoastrocytoma of the cerebellum: illustrated review R. Gil-Gouveia 1 , N. Cristino 2 , J. P. Farias 2 , A. Trindade 2 , N. S. Ruivo 3 , and J. Pimentel 1 1 Laboratory of Neuropathology, Institute of Molecular Medicine, Hospital de Santa Maria, Lisboa, Portugal 2 Neurosurgery Department, Hospital de Santa Maria, Lisboa, Portugal 3 Neuroradiology Department, Hospital de Santa Maria, Lisboa, Portugal Received August 21, 2003; accepted July 13, 2004; published online September 30, 2004 # Springer-Verlag 2004 Summary Although rarely, the usually benign, supratentorial, grade II astrocytic tumour pleomorphic xanthoastrocytoma (PXA) may arise from the cere- bellum. A review of the published cases of these PXAs is made including the author’s own case of a 40 years-old man with a right cerebellopontine angle tumour, which recurred after a gross total resection. The major clinical and histopathological features of cerebellar PXAs are discussed, and factors playing a role in their biological behaviour, like post-surgical medical treatment, genetics and extent of leptomenin- geal seeding are stressed. Keywords: Cerebellum; glioma; pleomorphic xanthoastrocytoma. Introduction Since its first description [8] in 1979, pleomorphic xanthoastrocytoma (PXA) is a well-recognized grade II astrocytic neoplasm with good prognosis, despite the potential for aggressive behaviour [10]. Most frequently, it is a supratentorial, superficial tumour with meningeal involvement, a neoplasm of young adults, presenting with long lasting epilepsy. Microscopically, there is a conspicuous cellular pleomorphism, intracellular accu- mulation of lipids, heavy reticulin network, and usually scarce mitotic activity and absence of necrosis [2, 8–11]. Few cases of atypical location have been described, mostly in the cerebellum [1, 4–6, 13, 14, 16]. A few descriptions of composite PXA and ganglioglioma [13] (PXA-GG) exist, which are also frequently found in the cerebellum [1, 6, 13, 14]. A matter of discussion on PXAs regards the role of the extent of surgical resection, and the meaning of some anaplastic changes, e.g. presence of mitosis or=and ne- crosis, on their biological behaviour [1, 2, 4, 6, 8–10]. We review the literature on cerebellar PXAs regarding clinics, histological features and biological behaviour, add an additional case and stress the factors which may contribute for the biological behaviour of these tumours. Case report A 40 years-old male presented with a four months history of tension type-like headaches, progressive right hearing loss and occasional gait instability. On examination he had right sensorineural hearing loss and right leg and gait ataxia. Brain MRI (Fig. 1) showed a right cerebello- pontine angle mass with well-defined lobulated margins extending to the jugular foramen and closely contacting the VII, VIII, IX, X and XI ipsilateral cranial nerves. There was mild local mass effect without fourth ventricular deformity or hydrocephalus. The mass was removed through a right suboccipital retromastoid approach, with the patient lying in park bench position. The tumour was found to arise from the right cerebellar hemisphere and to be exophytic to the cerebellopontine angle. A solid, fibro-elastic, red, mass was easily dissected from the V, VII, VIII, and lower cranial nerves, and no invasion of bone or dura was noticed. Frozen sections suggested an astrocytoma. Peace-meal resection was performed, resulting in a gross total excision (Fig. 2). The patient sustained a transi- tory mild right facial paralysis, but did otherwise well in the post-opera- tive period, and no further treatment was given. Twenty-seven months after discharge, signs of tumour recurrence were evident on routine imag- ing procedure and a second gross total excision was performed. Microscopic examination of the first ressected tumour (Fig. 3), showed an astrocytic tumour permeating the overlying leptomeninge and surrounding cerebellum, disclosing typical pilocytic features intermingled with a component of marked pleomorphic lipidized ele- ments. No mitotic figures were found, although necrosis was present. Immunostaining study disclosed GFAP reactivity of both components of neoplastic astrocytes, while neuronal markers were negative. Prolifera- tive index was 3.4%. Accordingly, a grade II PXA was diagnosed, even in the presence of necrosis. The second ressected tumour had similar