Transformation of Juvenile Pilocytic Astrocytoma to Anaplastic Pilocytic Astrocytoma in Patients With Neurofibromatosis Type I
Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA. Journal of Pediatric Hematology/Oncology
(Impact Factor: 0.9).
07/2011; 33(5):e198-201. DOI: 10.1097/MPH.0b013e318205e230
Patients with juvenile pilocytic astrocytoma (JPA) and neurofibromatosis type I (NF-1) tend to have a more indolent course than those with sporadic tumors. In rare circumstances, transformation to anaplastic pilocytic astrocytoma (APA) has been known to occur in sporadic cases and is associated with exposure to ionizing radiation. We present 2 patients with NF-1 who were initially diagnosed with JPA that later transformed to APA. Both patients were not exposed to ionizing radiation but instead received alkylator chemotherapy before transformation. Possibility of conversion to APA should be considered in patients with NF-1 and JPA who have rapid tumor recurrence.
Available from: Michael Karremann
- "Therefore , further studies are necessary to confirm the high incidence of APA in children with cerebellar HGG, which might be explained by the fact that WHO grade I pilocytic astrocytomas are frequently found within the posterior fossa (Fernandez et al, 2003) and that WHO grade III APAs may follow the same pattern as their lowgrade counterparts. Some of the APAs might also have arisen from previous subclinical WHO grade I pilocytic astrocytoma within the cerebellum since such malignant transformation had been reported before (Fangusaro, 2009; Otero-Rodriguez et al, 2010; Peters et al, 2011). However, malignant transformation of a subclinical WHO grade I pilocytic astrocytoma still seems an extraordinary clinical rarity and is often associated with prior irradiation or chemotherapy. "
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High-grade glioma (HGG) of the cerebellum accounts for only 5% of paediatric HGG. Since little is known about these tumours, the present study aimed at their further characterisation.
Twenty-nine paediatric patients with centrally reviewed cerebellar HGG were identified from the HIT-GBM/HIT-HGG database. Clinical and epidemiological data were compared with those of 180 paediatric patients with cortical HGG.
Patients with cerebellar tumours were younger (median age of 7.6 vs 11.7 years, P=0.028), but both groups did not differ significantly with regard to gender, tumour predisposing syndromes, secondary HGG, primary metastasis, tumour grading, extent of tumour resection, chemotherapy regimen, or radiotherapy. Except for an increased incidence of anaplastic pilocytic astrocytoma (APA) in the cerebellar subset (20.7% vs 3.3% P<0.001), histological entities were similarly distributed in both groups. As expected, tumour grading had a prognostic relevance on survival. Compared with cortical HGG, overall survival in the cerebellar location was significantly worse (median overall survival: 0.92±0.02 vs 2.03±0.32 years; P=0.0064), and tumour location in the cerebellum had an independent poor prognostic significance as shown by Cox-regression analysis (P=0.019).
High-grade glioma represents a group of tumours with an obviously site-specific heterogeneity associated with a worse survival in cerebellar location.
Available from: Stamatis Sapountzis
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Pilocytic astrocytomas (PAs) are the most common brain tumor in children and typically have an excellent prognosis. However, some PAs show histologically anaplastic features. It is reported that PAs with anaplastic features often need the postoperative radiation and chemotherapy due to aggressiveness such as early local recurrence and dissemination. We describe an interesting case of primary anaplastic PA with good clinical course in the long-term.
A 10-year-old man presented with worsening headache and vomiting. Magnetic resonance imaging (MRI) showed a large cystic tumor with contrast-enhanced solid component in a right occipital lobe. Magnetic resonance spectroscopy (MRS) showed the decrease of N-acetylaspartate (NAA) and the increase of choline and lipids, which suggested the malignancy.
The patient was operated with an occipital lobectomy. The tumor was incompletely resected due to the deep invasion to the inner wall of lateral ventricle. Pathological diagnosis was a pilocystic astrocytoma with anaplastic features. Although aggressive features were suspected from magnetic resonance spectroscopy and pathological findings, the remnant tumor showed no recurrence for 8 years without any postoperative treatments.
PAs could exhibit variable behavior, and careful managements including wait-and-scan should be considered, because adjuvant therapies may cause child's growth disorder and malignant transformation.
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