IDH-Mutant Astrocytoma With Chromosome 19q13 Deletion Manifesting as an Oligodendroglioma-Like Morphology.

Partial deletions in chromosomes 1p and 19q are found in a subset of astrocytic tumors; however, it remains unclear how these alterations affect their histological features and prognosis. Herein, we present 3 cases of isocitrate dehydrogenase (IDH)-mutant astrocytoma with chromosome 19q13 deletion. In the first case, the primary tumor harbored an IDH1 mutation with chromosome 1p/19q partial deletions, which covered 19q13 and exhibited a durable initial response to radiotherapy and temozolomide (TMZ) treatment.