Adult recurrent pilocytic astrocytoma: Clinical, histopathological and molecular study
S Trabelsi1, N Mama2, M Ladib3
1Department of Cytogenetics, Molecular genetics and Reproductive Biology, Farhat Hached University Hospital, Street Ibn Eljazzar, 4000 Sousse, Tunisia.
Insights
Adult pilocytic astrocytoma (PA) can recur aggressively. Molecular analysis, including KIAA1549:BRAF fusion detection, is crucial for accurate diagnosis and prognosis in adult PA cases.
Area of Science:
- Neuro-oncology
- Pediatric Neurosurgery
- Molecular Pathology
Background:
- Pilocytic astrocytoma (PA) is a WHO grade I glial tumor, predominantly diagnosed in children.
- Adult PA cases exhibit distinct clinical behaviors and molecular alterations compared to pediatric counterparts.
- Genetic alterations serve as vital molecular markers for glioma diagnosis and prognosis.
Observation:
- A 58-year-old male presented with a right infratentorial tumor, initially diagnosed as PA.
- Post-complete resection, the patient developed a rapidly growing tumor at the operative site and a secondary pineal region tumor within two years.
- Immunohistochemistry (IHC), Multiplex Ligation Probe Amplification (MLPA), and Fluorescence In Situ Hybridization (FISH) were performed on both primary and recurrent tumors.
Findings:
- Neuroimaging and neuropathological findings indicated an unusual diagnosis of recurrent PA in an adult.
- MLPA and FISH analyses confirmed the diagnosis through the detection of the KIAA1549:BRAF fusion.
- Additional genetic findings provided insights into the aggressive nature of the recurrent tumor.
Implications:
- Molecular analysis, including genetic fusion detection, should be integrated with histopathology and neuroimaging for adult PA.
- This integrated approach is essential for refining prognostic assessments in adult pilocytic astrocytoma.
- Understanding the molecular basis of adult PA recurrence can guide future therapeutic strategies.
Background:
PA is a grade I glial tumor that mostly occurs in children. However, although apparently similar to paediatric PA, adult PA presents a different clinical follow-up that could arise from specific molecular alterations. A variety of genetic alterations have been identified as diagnostic or prognostic glioma molecular markers.
Material And Methods:
We describe a right infratentorial tumor that occurred in a 58-year-old man. Neuroimaging and neuropathological examination suggested PA as an initial diagnosis. The tumor was completely resected. Unexpectedly, two years later, a rapidly growing tumor on the operative site was observed with a second location in the pineal region. Immunohistochemical reactions (IHC), Multiplex ligation probe amplification (MLPA) and fluorescence in situ hybridization (FISH) was performed in both primary and relapse tumor.
Results:
Neuroimaging and neuropathological examinations suggested an unusual diagnosis for adult patients: a recurrent PA. Both MLPA and FISH analysis contribute to diagnostic confirmation by KIAA1549: BRAF fusion detection. Additional genetic results revealed interesting findings that justified the tumor aggressivity.
Conclusion:
Molecular analysis of adult PA cases should be routinely combined with histopathological and neuroimaging examination to further refine prognostic diagnoses.
