Introduction In routine diagnostic practice, overlapping expression of thyroid transcription factor-1 (TTF-1) has been observed in both primary and metastatic central nervous system (CNS) tumors. In addition, variability in sensitivity among different antibody clones further complicates interpretation, posing significant challenges for differential diagnosis. Clarifying the expression profile of TTF-1 across diverse CNS tumor entities is therefore essential for optimizing its clinical application.
