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Washington University Experience | NEOPLASMS (GLIAL) | PLNTY | 3K2 PLNTY (Case 3, Resection 2) CD 34 2
CD34 demonstrates widespread immunoreactivity in the tumor (3M1) and highlights numerous ramified “spider” cells within the adjacent cerebral cortex (3M2). ---- Additional data in this second resection (not shown): Additionally, neurofilament highlights a rare dysmorphic appearing neuron. Immunostain for p53 shows nuclear reactivity in a small subset of tumor nuclei. Ki-67 highlights a proliferation index of ~1%. GFAP focally stains tumor cells and cortical glia.---- Comment: The collective features of a low-grade neoplasm with 'oligodendroglial' phenotype, infiltrative growth pattern, paucity of dysplastic/dysmorphic 'neuronal elements', and widespread aberrant expression of CD34 are consistent with a polymorphous low-grade neuroepithelial tumor of the young (PLNTY). ---- An FGFR2 alteration (FGFR2-DACH2 fusion) was found by targeted next-generation sequencing on patient's prior biopsy.
