Fig. 3: Challenges in interpretation of MTAP immunohistochemistry. | Modern Pathology

Fig. 3: Challenges in interpretation of MTAP immunohistochemistry.

From: Utility of methylthioadenosine phosphorylase immunohistochemical deficiency as a surrogate for CDKN2A homozygous deletion in the assessment of adult-type infiltrating astrocytoma

Fig. 3

a An IDH-mutant astrocytoma showing positive MTAP staining in fine cytoplasmic processes with weakly positive internal normal controls (arrow head). b Loss of MTAP staining in an IDH-mutant astrocytoma showing weak positivity for the internal normal controls (arrow head). c An IDH-mutant astrocytoma showing loss of MTAP staining with intermixed non-neoplastic reactive astrocytes retaining MTAP positivity. d An IDH-mutant oligodendroglioma, with perinuclear halos that made MTAP interpretation challenging. The case was interpreted as MTAP deficient, although the tumor lacked CDKN2A HD.

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