WHO Grade II glioma (low-grade glioma [LGG]) is increasingly diagnosed as an incidental finding in patients undergoing MRI for many conditions. Recent data have demonstrated that such incidental LGGs are progressive tumors that undergo clinical transformation and ultimately become malignant. Although asymptomatic LGG seems to represent an earlier step in the natural course of a glioma than the symptomatic LGG, it is nonetheless impossible to predict at the individual level when the tumor will become malignant. The authors report the case of a 43-year-old woman with a right operculo-insular LGG that was incidentally diagnosed because of headaches. No treatment was proposed, and repeated MRI scans were performed for 6 years in another institution. Due to a slow but continuous growth of the lesion, the patient was finally referred to our center to undergo surgery. Interestingly, objective calculation of the velocity of the tumor’s diametric expansion demonstrated a sudden acceleration of the growth rate within the 5 months preceding surgery, with the development of contrast enhancement. Remarkably, the patient was still asymptomatic. An awake resection was performed with intraoperative electrical mapping. There was no functional worsening following surgery, as assessed on postoperative neuropsychological examination. Removal of 92% of signal abnormality on FLAIR MRI was achieved, with complete resection of the area of contrast enhancement. Neuropathological examination revealed a glioblastoma, and the patient was subsequently treated with concomitant radiotherapy and chemotherapy. Although a “wait and see” attitude has been advocated by some authors with respect to incidental LGG, our original case demonstrates that acute transformation to glioblastoma may nonetheless occur, even before the onset of any symptoms. Therefore, because the lack of symptoms does not protect from malignant transformation, we propose consideration of earlier resection in a more systematic manner in cases of incidental LGG.
Jérôme Cochereau, Guillaume Herbet, Valérie Rigau, and Hugues Duffau
Sam Ng, Guillaume Herbet, Anne-Laure Lemaitre, Jérôme Cochereau, Sylvie Moritz-Gasser, and Hugues Duffau
Early surgery in presumed asymptomatic patients with incidental low-grade glioma (ILGG) has been suggested to improve maximal resection rates and overall survival. However, no study has reported on the impact of such preventive treatment on cognitive functioning. The aim of this study was to investigate neuropsychological outcomes in patients with ILGG who underwent preventive surgery.
This was a retrospective analysis of a consecutive series of patients with ILGG who underwent awake surgery and who had presurgical and 3-month postsurgical neuropsychological assessments. Data were normalized into z-scores and regrouped by cognitive domains. Clinicoradiological data, histomolecular profile, and differences in z-scores (Δz-scores) were analyzed.
Forty-seven patients were included (mean age 39.2 ± 11.3 years). Twenty-eight patients (59.6%) underwent supratotal or total resections. All patients were still alive after a mean follow-up of 33.0 ± 30.8 months. Forty-one patients (87.2%) had stable (n = 34, 72.3%) or improved (Δz-score > 1; n = 7, 14.9%) neurocognitive outcomes after surgery. Six patients (12.8%) presented a slight impairment (Δz-score < −1) in at least one cognitive domain. The mean presurgical and postsurgical z-scores were comparable except in the psychomotor speed and attention domain. A significant correlation between presurgical executive functioning and tumor volume was reported, whereas the extent of resection and histomolecular profile did not impact neuropsychological outcomes.
Early surgical treatment in presumed asymptomatic patients with ILGG was associated with stable or improved neuropsychological outcomes in 87.2% of patients at 3 months, with only mild cognitive decline observed in 6 patients. In return, supratotal or total resections were achieved in most patients, and all patients were still alive at the end of the follow-up.