FISH analyses for 1p and 19q status on gliomas: Reporting an 8 years' experience from a tertiary care center in the Middle East.

Diffuse gliomas are the most common primary malignancies of the central nervous system (CNS). The 2016 edition of the World Health Organization (WHO) classification of CNS tumors opted to integrate current molecular data with the traditional histologic diagnosis in the definition of the disease. This integrated diagnosis offers a greater level of objectivity and helps in establishing more definitive diagnoses for tumors that may have been controversial on histology alone. The classification of gliomas may require FISH technique to identify chromosomal abnormalities. FISH is commonly used to identify 1p/19q codeletion, but many challenges are encountered in the process. In this study, we review the FISH results for 1p/19q codeletion of n = 85 diffuse glioma samples examined at a tertiary care center in the Middle East over a period of 8 years. We also conduct a literature review to study the potential role of DNA-microarray in the identification of 1p/19q deletions. Glioblastoma (GBM), WHO grade IV is the most common glioma type identified (n = 24; 29%). All oligodendrogliomas show 1p/19q codeletion (26/26) while 12.5% of GBMs have 1p/19q codeletion (3/24). Isolated 1p deletions are only identified in one case of diffuse astrocytoma, WHO grade II. Isolated 19q deletions are identified in oligoastrocytoma, anaplastic astrocytoma, and glioblastoma. FISH is the most commonly used technique to diagnose oligodendroglioma because it is a simple, effective, and accessible technique in settings with limited resources. However, the optimization process remains highly variable between laboratories. Microarray is a more objective technique that can provide more information about the genetic alterations of the tumor for better diagnosis and sub-classification of diffuse glioma types.

A child with refractory complex partial seizures, right temporal ganglioglioma, contralateral continuous electrical status epilepticus, and a secondary Landau-Kleffner autistic syndrome.

A 7-year-old, right-handed girl started to have seizures at age 1 year 4 months. She developed normally until age 4 when she had worsening of seizures with auditory verbal agnosia, complete aphasia, and a behavioral disorder fulfilling the diagnostic criteria of autism. Medical therapy failed. MRI revealed a right temporal tumor. Video/EEG monitoring at age 7 showed contralateral electrical status epilepticus in wakefulness and sleep and ipsilateral onset of seizures. Resection (ganglioglioma with excessive inflammation) resulted in seizure freedom and marked reduction of the autistic features. This case is unique for being, to our knowledge, (1) the first in which a lesion located in the right, rather than left, temporal lobe resulted in secondary falsely localizing left temporal lobe electrical status epilepticus with a clinical picture of Landau-Kleffner syndrome and autism, and (2) the fourth reported patient with lesional Landau-Kleffner syndrome to respond to resective surgery.