MIB1 and pineocytoma: Recently WHO 2021 has included in-frame small insertions in the KBTBD4 gene (Kelch repeat and BTB domain-containing protein 4) as a desirable criterion for diagnosis of PPTID [2] Histologically, grade 2 PPTID retains a high neurofilament expression, similar to pineocytomas, but with a Ki67/MIB-1 index of 6% to 10%, higher than pineocytomas [3, 7] While PPTID grade 3 retains a minimal neurofilament expression and an Ki67/MIB-1 index ranges from 10 to 20% [3].