Diagnostic challenges, management and outcomes of midline low-grade gliomas

J Neurooncol. 2014 Nov;120(2):389-98. doi: 10.1007/s11060-014-1563-6. Epub 2014 Aug 6.


Introduction: Low-grade gliomas (LGGs) are slow-growing and diffusely infiltrating tumours constituting 25-30 % of adult gliomas. Rarely, these tumours may arise in the cerebral midline, including the thalamus, hypothalamus, tectum and brainstem. Here we present a contemporary experience with midline LGGs.

Methods: Midline LGGs were identified from a retrospective database of adult patients who received a histological diagnosis of WHO grade II glioma between 2006 and 2012 at a single institution. Location, radiological data and clinical outcomes were collected. IDH1 status was assessed by immunohistochemistry.

Results: Eighteen patients with midline LGGs were identified, with a median age of 45. Most received biopsy upon diagnosis, though asymptomatic patients with tectal tumours underwent active surveillance. Oligodendroglial tumours were much less common than in a comparable group of lobar tumours (6 vs. 38 %, Fisher's exact test, p = 0.007). Only one tumour was immunopositive for IDH1 (1/17). Radiological diagnosis correlated with histology in only 71 % of patients. Median survival of midline LGGs was 48 months (3-90 months) and radiological features such as contrast enhancement, size and radiological diagnosis did not predict survival in this cohort. Median overall survival of midline LGGs was less than lobar LGGs (log-rank, p = 0.006), though differences became insignificant when considering only biopsied astrocytomas in both locations (log-rank, p = 0.491).

Conclusions: Diagnosis of midline LGGs is complicated by both limitations of biopsy and imaging. Midline tumours have a poorer prognosis compared to lobar equivalents and survival differences are probably due to the absence of significant surgical intervention in midline locations.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Brain Neoplasms / diagnosis*
  • Brain Neoplasms / mortality*
  • Brain Neoplasms / therapy
  • Combined Modality Therapy
  • Disease Management
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Glioma / diagnosis*
  • Glioma / mortality*
  • Glioma / therapy
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Prognosis
  • Retrospective Studies
  • Survival Rate
  • Young Adult