FISHing for 1p19q codel in oligodendroglioma

@#Together with isocitrate dehydrogenase (IDH) mutation, co-deletion of 1p19q (1p19q codel) is a prerequisite for diagnosis of oligodendroglioma, making it imperative that histopathology laboratories introduce testing for 1p19q codel. To date there is still no consensus reference range and cut-offs that confirm deletion of 1p or 19q. We embarked on determining our reference range in 11 formalinfixed, paraffin-embedded non-neoplastic brain tissue using fluorescence in situ hybridisation (FISH) with the Vysis 1p36/1q25 and 19q13/19p13 FISH Probe Kit (Abbott Molecular Inc., USA). At same time we attempted to validate our methodology in 13 histologically-confirmed IDH-mutant oligodendrogliomas. For 1p, percentage cells with deletion (range=8-23%; mean±SD = 15.73±5.50%) and target: control (1p36:1q25) ratio (range = 0.89-0.96; mean±SD = 0.92±0.03) in non-neoplastic brain, differed significantly (p<0.000) from oligodendroglioma (percentage cells with deletion: range = 49-100%; mean±SD = 82.46±15.21%; target:control ratio range:0.50-0.76; mean±SD = 0.59±0.08). For 19q, percentage cells with deletion (range = 7-20%; mean±SD = 12.00±3.49%) and target:control (19q13/19p13) ratio (range:0.90-0.97; mean±SD = 0.94±0.02) in non-neoplastic brain also differed significantly from oligodendroglioma (percentage cells with deletion: range = 45-100%; mean±SD = 82.62±18.13%; target:control ratio range:0.50-0.78; mean±SD = 0.59±0.09). Using recommended calculation method, for diagnosis of 1p deletion, percentage of cells showing deletion should be >32-33% and/or target:control ratio <0.83. For 19q, percentage of cells showing deletion should be >22% and target:control ratio <0.88. Using these cut-offs all 13 oligodendroglioma demonstrated 1p19q codel.

Oligodendroglioma with Sarcomatous Transformation: Case Report and Literature Review

Oligodendrogliomas are infiltrative tumors of the central nervous systemconsidered to be morphologically stable and to offer a better prognosis. Here, we describe the case of a 36- year-old man with an initial diagnosis of oligodendroglioma, World Health Organization (WHO) grade II, who presented transformation to a sarcomatous form, while maintaining the oligodendroglial component as well as the genetic characteristics of the initial tumor without having undergone any complementary treatments previously. Despite the favorable genetic characteristics, the tumor presented poor response to complementary treatments, and rapid progression, including spinal metastasis.

1p/14q co-deletion: A determinant of recurrence in histologically benign meningiomas.

Background: Meningiomas are the most common benign central nervous system tumors. However, a sizeable fraction recurs, irrespective of histological grade. No molecular marker is available for prediction of recurrence in these tumors. Materials and Methods: We analyzed recurrent meningiomas with paired parent and recurrent tumors by fluorescence in situ hybridization for 1p36 and 14q32 deletion, AKT and SMO mutations by sequencing, and immunohistochemistry for GAB1, progesterone receptor (PR), p53, and MIB-1. Results: 18 recurrent meningiomas (11 grade I, 3 grade II, 4 grade III) with their parent tumors (14 grade I, 2 grade II and 2 grade III) were identified. Overall, 61% of parent and 78% of recurrent meningiomas showed 1p/14q co-deletion. Notably, grade I parent tumors showed 1p/14q co-deletion in 64% cases while 82% of grade I recurrent tumors were co-deleted. AKT mutation was seen in two cases, in both parent and recurrent tumors. SMO mutations were absent. GAB1 was immunopositive in 80% parent and 56.3% recurrent tumors. MIB-1 labeling index (LI), PR and p53 expression did not appear to have any significant contribution in possible prediction of recurrence. Conclusion: Identification of 1p/14q co-deletion in a significant proportion of histologically benign (grade I) meningiomas that recurred suggests its utility as a marker for prediction of recurrence. It appears to be a better predictive marker than MIB1-LI, PR and p53 expression. Recognition of AKT mutation in a subset of meningiomas may help identify patients that may benefit from PI3K/AKT pathway inhibitors, particularly among those at risk for development of recurrence, as determined by presence of 1p/14q co-deletion.

Primary Spinal Cord Oligodendroglioma with Postoperative Adjuvant Radiotherapy: A Case Report

Primary spinal cord oligodendrogliomas are rare tumors comprising two percent of all spinal cord tumors. Although a treatment guideline has yet to be established, maximal surgical resection is primary in the treatment of spinal cord oligodendrogliomas. Adjuvant radiotherapy has remained controversial, and it is unclear whether chemotherapy adds any benefit. In this case report, the authors present a 24-year-old male who had a seven-year history of left leg weakness and a radiating pain in both legs. Magnetic resonance image (MRI) showed an intramedullary mass at the T4-T8 level. He underwent subtotal removal of the tumor and pathologic diagnosis revealed a WHO grade II oligodendroglioma. The patient was treated with radiotherapy postoperatively and followed up with MRI annually. Clinical and radiological status of the patient had been stationary for four years after the surgery. The five-year follow-up MRI showed an increase in the size and extent of the residual tumor. Despite radiological progression, considering that symptoms and the performance status of the patient had remained unchanged, further treatment has not been performed. Given the clinical outcome of this patient, close observation after subtotal removal with adjuvant radiotherapy is one of the acceptable treatment options for WHO grade II spinal cord oligodendrogliomas.