Neuroendocrine Neoplasms of the GI Tract: Diagnosis, Reporting, and Clinical Correlates
Although neuroendocrine neoplasms (NEN) are encountered at virtually every anatomic site, the GI tract is the most common site of involvement. These tumors are common enough to be routinely encountered, but uncommon enough for most general pathologists to feel they haven’t achieved diagnostic mastery. This lack of comfort is further attributable to frequently shifting classification schemes and an ever-expanding list of applicable immunohistochemical markers. This lecture will focus on the most frequent diagnostic errors, challenges, and questions that are encountered in a neuroendocrine-heavy practice. Updates from the 2022 WHO Endocrine/Neuroendocrine Tumor Blue Book and the contemporary WHO classification of gastroenteropancreatic (GEP) NENs (contrasting it with the lung classification) will be presented. A brief discussion of the application of Ki-67 to NEN grading and GEP-neuroendocrine tumor (NET) site-specific diagnostic and reporting considerations will follow. Diagnostic algorithms for NET site of origin, neuroendocrine carcinoma (NEC) site of origin, and the distinction of NET G3 from NEC will be shared. A presentation of the essential elements of a NEN pathology report concludes the video.
