Artikel
Patterns of tumor recurrence in adult and childhood pilocytic astrocytomas: a clinico-pathological follow-up series over 10 years
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Veröffentlicht: | 20. Mai 2009 |
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Gliederung
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Objective: Pilocytic astrocytomas are typical tumors of infancy but also occur in adulthood. According to WHO, they are classified as grade I tumors. In recurrent tumors, however, dedifferentiation can be observed. The goal of the present retrospective study was to determine differences of tumor histology and prognosis between the adult and childhood pilocytic astrocytoma.
Methods: We performed a retrospective analysis of 47 consecutive patients (33 children and 14 adults) with astrocytoma WHO I° who were treated between 1996 and 2006 at our institution. The mean follow-up period was 54 months in the childhood and 44 months in the adulthood population. Tumor localization, age of the patients and histological features were analyzed and correlated with the course of the disease.
Results: No residual tumor was found on post-operative MRI scans in 40 cases. In 3 patients (7.5%) residual tumor of <5% was observed. 12 patients (25.5%) developed a recurrence and were reoperated; 7 of them were children, 5 adults. Among these 12 patients, 5 (10.6%) developed a second recurrence (3 children and 2 adults). The primary tumors which recurred were all located in the brainstem. All recurrent tumors in pediatric patients were histologically classified as pilocytic astrocytomas WHO grade I and showed a tumor labeling index of <5%. On the other hand, recurrences in 4 adult patients (80%) were classified as WHO grade III tumors with a labeling index of ±15%, and only 1 still as WHO I°. Initial immunohistochemical staining of neurofilaments and synaptophysin was positive in 11 (91.7%) patients who later developed a recurrence, and negative in all patients without recurrent tumor.
Conclusions: Our data suggest that recurrent pilocytic astrocytomas in adults have a high tendency towards dedifferentiation in contrast to children. Furthermore, our data demonstrate that immunohistochemical staining of neurofilaments and synaptophysin may provide additional prognostic information regarding further tumor development.