Artikel
Progression of a ganglioglioma WHO grade II into a malignant glioma. Report of two cases and review of the literature
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Veröffentlicht: | 20. Mai 2009 |
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Objective: Gangliogliomas (GG) are rare tumors of the central nervous system mostly presenting with a biphasic differentiation pattern with glial and neuronal cell elements. Seizures are the most frequent symptom. The tumors are predominantly located in the temporal lobe (79%), more rarely in the frontal region. A recurrence rate of 3% for all GG (WHO I° to III°) is reported in the literature. In the case of GG WHO II° the rate is 18%. Malignant progression, still less frequent, generally emanates from the glial part, as it occurred in our cases.
Methods: 1st case: 39-year-old man presenting with complex partial seizures in Oct. 2003. Magnetic resonance imaging (MRI) revealed a left temporal non-enhancing lesion. The lesion was resected without residual tumor in the MRI control. Histopathology showed glial and neuronal tumor cell components leading to the final diagnosis of GG WHO II°. In Sept. 07, MRI showed a recurrent non-enhancing tumor. Reoperation was done.
2nd case: 23-year-old woman presenting with a generalized seizure in May 2005 due to a left frontal non-enhancing lesion in MRI. Resection was done the same month. No residual tumor could be seen on the postoperative MRI. Histopathology revealed a GG WHO °II. In Feb. 2008, MRI showed a tumor progression with an enhancing tumor mass in the resection area. Gross total removal was done in March 2008.
Results: Histopathological examination of the recurrent tumor in the first case showed an anaplastic astrocytoma without evidence of neuronal tumor cell elements. Postoperative radiotherapy was done and the patient is without recurrence until now. Histopathology in the second case revealed a glioblastoma. The patient received radiotherapy and concomitant temozolomide followed by 6 cycles of temozolomide.
Conclusions: Malignant transformation of low grade GG is rarely reported. Besides the neuronal tumor cell components the majority of GG exhibit astrocytic characteristics with GFAP-immunoreactive neoplastic cells. Malignant progression of a low grade GG is generally confined to this glial component. According to a large study of 184 patients in the literature, long-term epilepsy seems to be associated with a significantly reduced risk of tumor recurrence. In our two cases, already the first epileptic seizure led to the diagnosis of a lesion emerging as a GG. Despite the general consideration of this entity as a benign tumor a regular follow-up is mandatory to detect and treat a recurrence in time.