RESUMEN
BACKGROUND: The term pilomyxoid astrocytoma (PMA) was added to the World Health Organization Classification of Tumours of the central nervous system in 2007. Pilomyxoid tumors are grade II tumors, considered to be variants of pilocytic astrocytomas. We attempted to determine if positron emission tomography (PET), proliferative index (PI), and BRAF V600E mutation help better define PMAs. OBSERVATIONS: We report 5 patients' clinical and neuroimaging findings, pathology (PI), and outcome. Four of the 5 patients had PET scans. Three patients showed [18F]fluoro-deoxyglucose hypermetabolism. The PI was elevated in all 5 cases and the BRAF V600E mutation was found in 3 of the 3 patients tested. CONCLUSION: Our data suggest that PMAs are hypermetabolic on PET, have elevated PIs and BRAF V600E mutations, and behave aggressively.
Asunto(s)
Astrocitoma/genética , Astrocitoma/patología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Astrocitoma/diagnóstico por imagen , Neoplasias Encefálicas/diagnóstico por imagen , Proliferación Celular , Niño , Preescolar , Análisis Mutacional de ADN , Femenino , Humanos , Lactante , Masculino , Reacción en Cadena de la Polimerasa , Tomografía de Emisión de Positrones , Proteínas Proto-Oncogénicas B-raf/genéticaRESUMEN
BACKGROUND: Diffuse intrinsic brainstem gliomas (DIBSGs) in children remain difficult tumors to treat and have a very poor prognosis. Intensifying both chemotherapy and radiation programs have been attempted without success. Positron emission tomography (PET) has been used to differentiate benign from malignant tumors and may predict outcome. OBJECTIVES: To determine whether PET can characterize a specific metabolic pattern of DIBSGs and correlate this with patient survival. METHODS: We conducted a retrospective review of patients with DIBSGs and PET scans at diagnosis. Data for ¹8[F] fluorodeoxyglucose (FDG) and ¹¹C-methionine (CMET) PET scans were collected. Treatment and survival were reviewed. RESULTS: We identified 30 patients with DIBSGs, 25 of whom had FDG and/or CMET PET scans. Scans showed both focal and generalized metabolic activity, and the patterns showed no correlation with survival. Patients with both FDG and CMET positive scans had a mean survival of 380 days, whereas those negative for both isotopes had a mean survival of 446 days. CONCLUSIONS: There was no specific PET pattern identified in this DIBSG cohort but a trend toward improved survival was noted with absence of FDG and CMET metabolism. Metabolically active areas may suggest potential sites for biopsy. We believe that biopsy is essential for improving therapy for this patient population.