Consensus in Pituitary Pathology: Impact after New Classification for Japan

Naoko InoshitaJapan Speaker Consensus in Pituitary Pathology: Impact after New Classification for JapanIn Japan, the brain tumor handling rules are essentially based on the WHO classification. However, the introduction of the term pituitary neuroendocrine tumour (PitNET) has occasionally led to misunderstanding in clinical practice, particularly regarding the implication of malignancy. In this lecture, I will present a consensus-oriented approach in pituitary pathology, focusing on practical strategies developed through multidisciplinary collaboration for the benefit of clinicians and patients. First, I will show how the addition of touch smear cytology to frozen section diagnosis during surgery can improve the accuracy of margin assessment and increase the likelihood of achieving the intended surgical goal, including adequate removal of hormone-producing tumours. Second, I will emphasize that truly malignant PitNETs are extremely rare, and that the term “NET” should not be equated with malignancy. Third, I will discuss the well-known discrepancy between hormone immunohistochemistry and clinical functionality, highlighting the importance of careful pathological interpretation. These perspectives reflect our pathology team’s commitment to accurate communication and clinically relevant pathological diagnosis.