A tree-on-sunset appearance on narrow band imaging: A rectal neuroendocrine tumor peculiarity

Neuroendocrine tumors (NETs) correspond to a wide group of neoplasms that can arise from various parts of the body, with rectal NETs often being discovered incidentally during colonoscopies. This case report describes a 41-year-old female with a rectal NET identified during routine screening, displaying a distinct “tree-on-sunset” appearance on narrow-band imaging (NBI). The mass, confirmed as a well-differentiated grade 2 NET via endoscopic ultrasound (EUS) and biopsy, was resected using endoscopic mucosal resection (EMR). This report underscores the importance of advanced imaging techniques, such as NBI, in enhancing the accuracy of rectal NET diagnosis and encourages further studies to validate the diagnostic significance of such imaging features.