Primary Hepatic Neuroendocrine Tumor Treated With Lattice and External Beam Radiation: A Case Report.

Neuroendocrine tumors (NETs) originate from neuroendocrine cells, which receive neural input and play a key role in transmitting signals by secreting bioactive substances such as monoamines (e.g., serotonin), peptides (e.g., somatostatin), and hormones (e.g., insulin) that regulate a wide range of physiological functions. While NETs in the liver are typically metastatic, often originating from other sites in the gastrointestinal (GI) tract, they can, in rare cases, manifest as primary tumors in the liver. These are referred to as primary hepatic neuroendocrine tumors (PHNT). We present the case of a 62-year-old male patient diagnosed with PHNT confirmed through imaging and immunohistochemistry analysis. Given the rarity of this diagnosis, there are no established treatment guidelines for PHNT. In this case, lattice radiotherapy (LRT) via TomoTherapy (TomoTherapy, Inc. in Madison, WI) was selected as the first-line treatment approach for the tumor.