Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 58, Num. 6, 2010, pp. 972-974

Neurology India, Vol. 58, No. 6, November-December, 2010, pp. 972-974

Letter to Editor

Pediatric cerebellar pilocytic astrocytoma presenting with hemorrhage

Ashish Kumar, Chandrashekhar E Deopujari, Naresh Biyani, Mayur V Mhatre

Department of Neurosurgery, Bombay Hospital Institute of Medical Sciences, Mumbai - 400 020, Maharashtra, India
Correspondence Address: Ashish Kumar, Department of Neurosurgery, Bombay Hospital Institute of Medical Sciences, Mumbai - 400 020, Maharashtra, India, drashishmch@hotmail.com

Date of Acceptance: 17-Aug-2010

Code Number: ni10279

PMID: 21150081
DOI: 10.4103/0028-3886.73775

Sir,

Clinical presentation with spontaneous intracerebral hemorrhage in central nervous system tumors is an uncommon but a well described entity. Mostly, hemorrhage is seen in primary and metastatic central nervous system tumors. Pilocytic astrocytomas in posterior fossa rarely present with hemorrhage, and only sporadic case reports are available in the literature.

A 16-year-old girl presented with history of intermittent suboccipital headaches, gait disturbances and blurring of vision for 10-15 days with worsening of symptoms and recurrent episodes of vomiting in the last 2 days. Neurologic examination revealed bilateral papilledema and positive cerebellar signs. Cranial magnetic resonance imaging (MRI) revealed a right cerebellar solid-cystic lesion, which was isointense on T1-weighted images and hyperintense on T2-weighted images with irregular peripheral rim-like enhancement [Figure - 1]. The gradient echo sequence showed evidence of bleed within the tumor [Figure - 2]. She underwent midline suboccipital craniotomy and gross total excision of tumor. Intraoperatively, the tumor was highly vascular, and an organized blood clot was present within the lesion [Figure - 3]. The histopathology revealed typical biphasic pattern of pilocytic astrocytoma with compact areas marked by piloid cells and rosenthal fibers and loose microcystic areas along with hyalinization of vessels [Figure - 4]. Postoperative MRI after an interval of 3 months confirmed complete excision of tumor.

The reported rate of hemorrhage in primary gliomas has been around 3.7% to 7.2% (mainly in glioblastoma and oligodendrogliomas), while the low-grade astrocytomas account for less than 1% of cases. ^[1],[2] Lieu et al.^[2] reported an incidence of 3.5% in their series of 761 brain tumors. Acute cerebellar hemorrhage in adults occurs in 10% of the cases and is associated with hypertension and anticoagulant therapy. In children, acute cerebellar hemorrhage which is neoplastic in origin is very rare. Only a few case reports of cerebellar pilocytic astrocytoma presenting with hemorrhage are found in the literature. Mesiwala et al.^[3] reported a case of spontaneous intracerebellar hemorrhage in posterior fossa pilocytic astrocytoma in 2001, and only 6 other cases of intratumoral bleed in pediatric posterior fossa tumors were found by them in literature since 1977. In their first ever series assessing the rate of spontaneous hemorrhage in histologically proven pilocytic astrocytomas, White et al.^[4] reviewed 138 cases in both supratentorial and infratentorial locations during a span of 11 years, with 8% of cases presenting with hemorrhage. They concluded that there was no particular location susceptible for hemorrhage; however, no bleeding occurred in cerebellum in their series. The etiology of intratumoral hemorrhage in pilocytic astrocytomas is unclear. In contrast to higher-grade tumors, where hemorrhage has been linked to rapid tumor cell proliferation, abundant neo-vascularization, and necrosis of blood vessels, the cause of hemorrhage in pilocytic astrocytomas is still debated, some possible explanations being endothelial proliferation, rupture of encased aneurysms and dysplastic capillary beds. Also, fibrinolytic activity due to the thromboplastin activity of brain tissue has been thought of as a contributing factor. Kondziolka et al.^[5] reported 24 cases of mixed oligodendroglioma-astrocytoma, of which 7 cases were associated with gross bleeding. There was no bleeding encountered within the cerebellum. A literature review by Joung et al.^[6] summarizes various sites and histological diagnosis in children with spontaneous cerebellar hemorrhage in the posterior fossa tumors [Table - 1]. Pilocytic astrocytomas, although benign, can present with hemorrhage evident on imaging at a higher rate than expected. Their presentation seems to be acute in nature, and high index of suspicion is required in the diagnosis of these posterior fossa tumors, which can deteriorate rapidly.

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