Acute progression of untreated incidental WHO Grade II glioma to glioblastoma in an asymptomatic patient

Abstract

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.

Surgical management of incidentally discovered diffusely infiltrating low-grade glioma

“…Recent studies have demonstrated that iLGGs grow at a velocity similar to their symptomatic counterparts. 7,20 Not only do iLGGs grow over time, they may also undergo malignant degeneration even in asymptomatic patients. 8,12 Our results demonstrate that tumor volumes increase by about 20 cm 3 over an average of 28 months, and in 1 extreme case rapid progression with malignant transformation occurred that ultimately led to the patient's demise (Fig.…”

“…19 Also, in their most recent case report, Cochereau et al illustrate the fact that there can be acute malignant transformation of iLGGs even when the patient remains symptom free. 7 We set out to review a series of cases of iLGGs treated during a period when the general approach at our institution was "watch-and-wait" to determine the characteristics of these tumors and treatment outcomes.…”

Imaging practice in low-grade gliomas among European specialized centers and proposal for a minimum core of imaging

“…Newly apparent contrast enhancement indicating breakdown of the blood brain barrier represents the classical sign of malignant transformation (MT) of these tumors [ 30 ], but preceding changes in advanced MRI investigations may allow identification of patients at risk up to 12 months earlier [ 31 ]. Simple measurement of growth rate [ 19 , 32 , 33 ] and integration of MR spetroscopy [ 18 , 19 , 34 ] are used routinely in most of the centers as predictors of tumor transformation. Both, proton- and phosphorus spectroscopy, available in numerous centers, have been proven to correlate with Ki67 and IDH1 mutation [ 35 ].…”

Multimodal Assessment Shows a Mostly Preserved Cognitive Status in Incidentally Discovered Low Grade Gliomas: A Single Institution Study

“…Patients with iLGGs represent an extremely rare clinical subgroup of LGGs; the incidence ranging between 0.04 and 0.2% in the general population [11]. The natural history of iLGGs prior to discovery is poorly understood [2,12], and the question of clinical management has become a topic of increasing interest in current literature [1][2][3][13][14][15][16][17][18][19][20][21]. None of the above-mentioned studies presented neuropsychological data about patients with incidental brain tumors.…”