MAPT and Alzheimer disease: The attribution of different diagnoses to the same inclusions (ECH tau pathology) based upon extrinsic characteristics (presence or absence of AD-associated Aβ deposits) could well be less effective than regrouping under the same term similar inclusions that have different extrinsic characteristics, as has recently been done for “tauopathies,” “synucleinopathies,” or “fronto-temporal lobar degeneration-TDP-type.” Moreover, the extrinsic characteristics that permit the diagnosis of PART raise questions that two hypothetical examples will help to illustrate.