FRONTAL LOBE TUMORS AND THEIR SURGICAL MANAGEMENT

Volume 3 Issue 4 April, 2013

Consultation Liaison Psychiatry Focus: Neurosurgery

The frontal lobe tumours by definition are intra axial arising from within the brain parenchyma (gliomas). However extrinsic tumors originating from the neighboring structures like meninges ( meningiomas) would present with similar clinical features. The gliomas can be astrocytomas, oligodendrogliomas, ependymomas,with subvarieties and also mixed types. Several new tumor types have been added recently by WHO (2007). The lower grade tumors (1& 2) have longer survival compared to higher grade (3 & 4) tumors. Grade ‐4 tumor also known as Glioblastoma multiforme is probably the most malignant tumor known. The extra axial tumors can be varied like meningiomas or inflammatory lesions which behave like tumors eg. Tubercular, bacterial or fungal abscesses.

The clinical features may so much simulate a psychiatric disorder that they are referred to a Psychiatrist. Basal frontal lobe tumors present with pseudomania, lateral frontal with pseudodepression, medial frontal with pseudodementia. Apathy, change in personality, memory impairment, inappropriate social behavior, incontinence are all common features. Left frontal tumors cause greater loss of IQ in right handed individuals. Also speech may be affected in tumors arising in speech areas of left frontal lobe. Neighbourhood signs include anosmia, visual deterioration owing to compression on the cranial nerves. Pseudo cerebellar signs with ataxia and tremors may be seen in some of the patients. Adversive fits with head and eyes turning to opposite side may be seen in lateral frontal lobe tumors. Tumors in motor strip may cause focal or generalized seizures by irritation or may cause paralytic effects on contarlateral half or part of the body by pressure effects. Raised ICP features in later stages due to increased volume of the tumor would result in headache, vomiting, blurring of vision. Further progress would cause deterioration in consciousness progressing to coma and death.

The imaging includes mainly Contrast enhanced CT scan of the brain in suspected cases. But the MRI is essential for most of the cases prior to surgery for planning the operative approach apart from gaining information about the nature of the tumor.

Management is by surgery. It involves total excision of benign tumors like meningiomas or epidermoids or inflammatory lesions aiming to give ‘cure’ for the patient. However in case of gliomas radical resection by removal of as much of the tumor from the healthy parenchyma as seen under the Operating Microscope is now the standard dictum. This gives the specimen for HPE and the reduces the central bulk of the tumor which poorly responds to Radiotherapy as the latter acts mainly on the dividing cell lines in the periphery of the tumor. The extent of the tumor resection has been shown to be directly proportional to the longevity of the survival. However it may have to be restricted at times to prevent fresh neurological deficits. Routinely patients improve after tumor resection unless they come too late with advanced raised ICP features.

The higher grade gliomas Grade 3/4 will require Radio and chemotherapy. The median survival in high grade gliomas is one year although 10‐20% has been living for even 2‐3 years. The survival in low grade gliomas is better with few years from 4‐8 years.