Contributed by Simon Chiosea, MD
Published on line in February 2007
A 38-year-old man, status 8 months post resection of his anaplastic oligodendrogioma of the right frontal lobe presented for a monitoring magnetic resonance imaging (MRI). The imaging studies revealed a slight interval increase of the minimally enhancing nodular mass consistent with the recurrent tumor (Figure 1). The patient received 6 cycles of temozolomide. Past medical history included frontal sinus infection and temporal mandibular joint dysfunction.
Resection of the mass yielded a 3x3x0.5 cm fragment of grey-pink brain tissue with gelatinous consistency and myxoid cut surface (Figure 2). No calcium deposits were seen. The intraoperative consultation showed "chicken wire" network of thin-walled blood vessels and monomorphic small round nuclei with open chromatin (smear, H&E, Figure 3). The background consisted of a dense network of glial processes. On permanent sections a prototypical perinuclear halo ("fried egg", an artifact of delayed fixation) and conspicuous mitotic activity was seen (Figure 4). The tumor resected 8 months ago was characterized by allelic losses on chromosomes 1p and 19q, as demonstrated by fluorescence in situ hybridization (Figure 4, insets). The proliferative index focally was up to 25%. EGFR was not amplified. P53 immunoreactivity was not increased.