Molecular imaging in pituitary neuroendocrine tumors: a narrative review of advances, challenges, and future perspectives

Molecular imaging has emerged as a promising adjunct for the evaluation of pituitary neuroendocrine tumors (PitNETs), as magnetic resonance imaging (MRI), despite being the primary imaging modality, remains inconclusive in a substantial proportion of patients. Molecular imaging techniques, including single photon emission computed tomography (SPECT) and positron emission tomography (PET), can complement anatomical MR imaging by enabling in vivo visualization of tumor metabolism, receptor expression, and amino acid transport. This narrative review summarizes current evidence on the clinical utility of molecular imaging across corticotroph, somatotroph, lactotroph, and nonfunctioning PitNETs, with a focus on diagnostic performance and impact on patient management. Among available tracers, amino acid PET shows the most consistent added diagnostic value in patients with inconclusive MRI findings, particularly when integrated into hybrid or coregistered PET-MRI protocols. Emerging data indicate that this approach improves tumor localization and supports clinical decision-making, including surgical planning and management of persistent or recurrent disease. Defining the precise role of molecular imaging within endocrine diagnostic pathways will require larger-scale prospective clinical trials using standardized acquisition and interpretation protocols. Broader clinical implementation is further supported by emerging European interdisciplinary collaborations between experts in endocrinology, nuclear medicine, radiology, neurosurgery, and radiotherapy, with a shared focus on advancing individualized PitNET care.