Artikel
Pediatric supratentorial primitive neuroectodermal tumor with differentiated astrocytic component and its malignant transformation featured by aggressive biological behaviour : a case history
Ein kindlicher supratentorieller primitiver neuroektodermaler Tumor mit einer differenzierten astrozytären Komponente und deren maligner Transformation gekennzeichnet durch aggressives biologisches Verhalten: eine Fallstudie
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Autoren
Veröffentlicht: | 4. Mai 2005 |
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Gliederung
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Objective
Primitive neuroectodermal tumors (PNET) are known for their peculiarity to contain differentiated or anaplastic astrocytes, thereby indicating a worse prognosis because of less sensitivity to chemo- or radiotherapy. Here, we report the case of a seven-year old boy with astrocytic differentiation within PNET.
Results
When the boy was five, he experienced a generalized seizure. Magnetic resonance imaging revealed a well circumscribed left-sided occipital lesion. Histopathologic diagnosis of the removed tumor revealed the picture of a primitive neuroectodermal tumor with small blue tumor cells and expression of microtubule-associated protein 2C and neuron-specific enolase. Glial fibrillary acidic protein, epithelial membrane antigen, synaptophysin, cytokeratin protein LU-5, neurofilament protein, and actin were negative. Ki67 index was as high as 50%. Postoperatively, “HIT 2000 protocol” was applied. After 3 months, a new contrast medium uptake at the resection rim was diagnosed and was progressive 5 months later. Surgically removed recurrent tumor showed the features of an astrocytoma WHO grade II without a PNET-like component. Tumor cells were positive for GFAP and S-100 protein. Neuronal markers as synaptophysin, MAP2C, and NSE were negative. Ki67 proliferation index was less than 2%. After 13 months, the child developed severe neurological deterioration caused by a massive tumor relapse involving almost the whole left hemisphere. Surgical resection of tumor bulk was performed as well as “HIT Rezidiv 1997 protocol”. Diagnosis of a supratentorial primitive neuroectodermal tumor with glioblastoma components according to WHO grade IV was established. Tumor cells were positive for GFAP and MAP2C. Proliferation fluctuated from 20% in glioblastoma components to 50% in PNET areas. Deletions detected in analysis of loss of heterozygosity (LOH) of PNET and astrocytoma WHO grade II divided into two groups. One group comprised deletions being present in both the PNET and the low-grade astrocytoma part. Other deletions were present only in the astrocytoma area. Vice versa, deletions specific to the PNET were not detected. Other markers did not show any deletions within both tumor parts.
Conclusions
We discussed for the first time a case of primitive neuroectodermal tumor with astrocytic differentiation and subsequent malignant transformation, in which LOH analysis revealed a common origin of PNET and astrocytoma components with progressive allelic loss.