Meningiomas múltiplos e neurofibromatose: relato de três casos

Meningiomas múltiplos «verdadeiros" geralmente não constituem entidade patológica específica. Em geral, associam-se a neurofibromatose. As clássicas lesões externas, descritas por von Recklinghausen, associadas à neurofibromatose, podem não estar presentes. Isto poderia ser possível devido à penetrância variável de aberrações cromossômicas ligadas ao cromossomo 22. Estudos moleculares desses tumores confirmam esta hipótese. Em nossa série de 108 pacientes com diagnóstico de meningioma intarcraniano, apenas três eram múltiplos. Apenas em um caso, estigmas externos de neurofibromatose foram encontrados. Os dois casos que não apresentavam qualquer estigma foram considerados como meningiomas múltiplos «verdadeiros". Na ausência de manifestações cutâneas habitualmente associadas à neurofibromatose, é extremamente difícil distinguir meningiomas múltiplos associados a neurofibromatose dos assim chamados meningiomas múltiplos verdadeiros. Em nossa opinião não há justificativa para se considerar meningiomas múltiplos como entidade patológica independente

Assessment of successful incorporation of cages after cervical or lumbar intercorporal fusion with [(18)F]fluoride positron-emission tomography/computed tomography

The purpose of this study is to assess the successful incorporation of cages in patients after cervical or lumbar intercorporal fusion with positron-emission tomography/computed tomography (PET/CT). Twenty patients (14 female and 6 male; mean age 58 years, age range 38–73 years) with 30 cervical (n = 13) or lumbar (n = 17) intercorporal fusions were prospectively enrolled in this study. Time interval between last intercorporal intervention and PET/CT ranged from 2 to 116 months (mean 63; median 77 months). IRB approval was obtained for all patients, and written informed consent was obtained from all patients. About 30 min prior to PET/CT scanning, 97–217 MBq (mean 161 MBq) 18F-fluoride were administered intravenously. Patients were imaged in supine position on a combined PET/CT system (Discovery RX/STE, 16/64 slice CT, GE Healthcare). 3D-PET emission data were acquired for 1.5 and 2 min/bed position, respectively, and reconstructed by a fully 3D iterative algorithm (VUE Point HD) using low-dose CT data for attenuation correction. A dedicated diagnostic thin-slice CT was optionally acquired covering the fused region. Areas of increased 18F-fluoride uptake around cages were determined by one double-board certified radiologist/nuclear physician and one board certified radiologist in consensus. In 12/20 (60%) patients, increased 18F-fluoride uptake around cages was observed. Of the 30 intercorporal fusions, 15 (50%) showed increased 18F-fluoride uptake. Median time between intervention and PET/CT examination in cages with increased uptake was 37 months (2–116 months), median time between intervention and PET/CT examination in those cages without increased uptake was 91 months (19–112 months), p (Wilcoxon) = 0.01 (one-sided). 14/29 (48%) cages with a time interval > 1 year between intervention and PET/CT scan showed an increased uptake. In conclusion, PET/CT frequently shows increased 18F-fluoride uptake in cervical and lumbar cages older than 1 year (up to almost 8 years in cervical cages and 10 years in lumbar cages) possibly indicating unsuccessful fusion due to increased stress/microinstability