ABSTRACT
A 10-year-boy post-operative, post-radiotherapy case of left temporal glioblastoma multiforme (GBM) was referred for F-18 Flurodeoxyglucose (FDG) Positron emission tomography/Computed Tomography (PET/CT) to rule out residual/recurrent disease 6 months following completion of therapy. The FDG scan 3 months following therapy had not shown evidence of viable residual or metastatic disease. The present scan showed a tiny focus of abnormal FDG accumulation in the region of the trigone of the left lateral ventricle which was best appreciated on the plain PET image. A correlative C-11 methionine study showed a well defined focus of abnormal tracer accumulation in the region of the left trigone. CECT and MRI done subsequently proved it to be a subependymal deposit. This case therefore demonstrates the possibility of subependymal deposits in GBM and the need for this possibility to be entertained during interpretation of the FDG study. It also highlights the advantage of labelled amino acids like C-11 methionine for clearly delineating subependymal deposits apart from the advantage for unequivocal interpretation of the PET study in recurrent brain tumors.
ABSTRACT
We report a case of a 60-year-old woman, diagnosed as a case of non Hodgkins lymphoma (NHL), referred for F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) following 6 cycles of chemotherapy to evaluate response to therapy. The scan revealed a curvilinear pattern of FDG accumulation in the midline extending anteroposteriorly, just adjacent to the inner table of the skull on the fused PET/CT images with no corresponding abnormality on the low-dose CT. Because this site anatomically corresponded to that of the sagittal sinus, an MRI and magnetic resonance venography was advised which confirmed the presence of sagittal sinus tumor deposits. This case highlights the pattern of sagittal sinus tumor thrombosis on FDG PET/CT and the possibility of its occurrence in NHL.
