{'fraction_non_alphanumeric': 0.03426791277258567, 'fraction_numerical': 0.017133956386292833, 'mean_word_length': 5.090047393364929, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Pediatric and adolescent oligodendrogliomas.

PURPOSE
To review the clinical and imaging findings in pediatric and adolescent intracranial pure oligodendrogliomas.


METHODS
The clinical, CT, and MR data in 39 surgically proved pure oligodendrogliomas were retrospectively reviewed.


RESULTS
The frontal or temporal lobes were involved in 32 (82%) cases. Seventy percent of the tumors were hypodense on CT, three-fourths were hypointense on T1-weighted images, and all were hyperintense on spin-density and T2-weighted images. Fewer than 40% of the lesions demonstrated calcification, and nearly 60% had well-defined margins. Mass effect was seen in fewer than half of the cases, and edema could be separately identified in only one case. Tumor enhancement was seen in fewer than 25%. In 39 cases after partial (3), subtotal (16), or total (20) resection, follow-up studies demonstrated stability over a mean period of 5 years.


CONCLUSION
The findings in this pediatric series of pure oligodendrogliomas (without mixed cell elements) differ from previous adult series in that calcification, contrast enhancement, and edema are seen less frequently. In addition, very slow or no growth is often characteristic, and these patients have an excellent prognosis with surgical resection.