Awake Craniotomy for a Left Frontal Lobe Oligodendroglioma
A 48-year-old woman with new-onset seizures was found to have a 5 cm left frontal lobe tumor involving the prefrontal cortex near language and executive networks. Awake functional mapping, 5-ALA fluorescence, tractography and high-resolution neuronavigation supported gross total resection while preserving language, motor and cognitive function.
A large frontal lobe tumor beside language and executive networks
A 48-year-old woman presented with a three-month history of episodic “spacing out,” progressing to right-arm clonic jerks with secondary generalization — a pattern consistent with a frontal lobe seizure focus. Her neurologic examination was normal aside from subtle executive dysfunction identified on formal testing. There were no objective motor or sensory deficits.
MRI demonstrated a 5 cm non-enhancing T2/FLAIR-hyperintense mass in the left frontal lobe, centered in the prefrontal cortex and abutting the anterior horn of the lateral ventricle. Punctate calcifications and minimal surrounding edema were also present, imaging features characteristic of oligodendroglial tumors.
Advanced MR spectroscopy demonstrated a prominent 2-hydroxyglutarate (2-HG) peak, strongly suggesting an IDH1 mutation before tissue diagnosis. Imaging and advanced diagnostic findings were reviewed by the multidisciplinary Brain Tumor Board to align the operative plan with anticipated neuro-oncologic management.
Why awake mapping for maximal safe resection?
Because the lesion was close to language and executive networks, the operative goal was not simply maximal tumor removal. It was maximal safe resection — removing as much tumor as possible while continuously identifying and protecting functional cortex and subcortical pathways.
The patient underwent an awake craniotomy with comprehensive motor and language mapping, coordinated by neuroanesthesia, neurophysiology and speech-language pathology. Integrated tractography and high-resolution neuronavigation provided anatomical and white-matter guidance throughout the procedure.
5-ALA fluorescence was used to enhance intraoperative visualization of tumor margins. A well-demarcated pink-gray tumor was encountered, with focal 5-ALA fluorescence at infiltrative margins. Stepwise internal debulking under continuous functional testing allowed circumferential mobilization while avoiding eloquent cortex and function-positive white-matter tracts.
The technical goal
Achieve gross total resection while preserving language, motor function and higher-order cognitive networks. Awake functional testing, fluorescence guidance, tractography and neuronavigation supplied complementary information as the resection approached functional boundaries.
From a 5 cm frontal lobe tumor to gross total resection
Preoperative imaging defined the tumor's extent and relationship to critical anatomy. Early postoperative MRI confirmed gross total resection.
with preserved language,
motor and cognitive function.
Gross total resection was achieved and confirmed on early postoperative MRI. There were no perioperative complications, and language and motor function remained intact.
Recovery was uneventful. Seizures were controlled with levetiracetam, and postoperative neurocognitive testing returned to baseline.
The molecular diagnosis shaped what came after surgery
Histopathology confirmed a CNS WHO grade 2 oligodendroglioma, with classic “fried-egg” cytology, microcalcifications and delicate branching capillaries. Mitotic activity was low at 1/mm², with no microvascular proliferation or necrosis.
Integrated molecular analysis identified an IDH1 R132H mutation and 1p/19q codeletion, the defining molecular combination for oligodendroglioma. The tumor also demonstrated MGMT promoter methylation, while CDKN2A/B remained intact.
Coordinated intraoperative tissue handling and expedited neuropathology workflows enabled comprehensive molecular profiling to inform prognosis and the postoperative treatment strategy.
Using molecular information to personalize adjuvant treatment
With gross total resection achieved and a favorable molecular profile — IDH-mutant, 1p/19q-codeleted and MGMT-methylated — the multidisciplinary team recommended deferring radiation and cytotoxic chemotherapy to reduce the potential for long-term neurocognitive toxicity.
With guidance from the multidisciplinary neuro-oncology team, the patient initiated vorasidenib, a targeted IDH-pathway inhibitor, to suppress 2-HG production and support ongoing disease control.
Why the sequence matters
Surgery established maximal cytoreduction and supplied the tissue needed for an integrated molecular diagnosis. The extent of resection, neurological outcome and molecular profile could then be considered together when selecting the postoperative strategy.
Modern glioma care connects surgical technique with molecular neuro-oncology
Oligodendroglioma management no longer stops at what a tumor looks like under the microscope. Surgical anatomy, functional preservation, extent of resection and integrated molecular pathology all contribute to treatment planning.
This case illustrates how an experienced multidisciplinary brain tumor program can connect advanced imaging, awake mapping, microsurgery, neuropathology and neuro-oncology into one coordinated treatment strategy.
Yaron A. Moshel, MD, PhD
Dr. Yaron Moshel is President of Atlantic Brain and Spine, Chair of Neurosurgery at Morristown Medical Center and Director of the Brain Tumor Center. His brain tumor practice includes awake functional mapping, fluorescence-guided surgery and other advanced techniques designed to maximize tumor treatment while preserving neurological function.
Meet Dr. MoshelDiagnosed with an oligodendroglioma or other glioma?
Our brain tumor team can review your imaging, pathology, molecular findings and treatment options — whether you are newly diagnosed, considering surgery or looking for a second opinion.
Request an Appointment