- Erdrich, Jennifer;
- Schaberg, Kurt;
- Khodadoust, Michael;
- Zhou, Li;
- Shelton, Andrew;
- Visser, Brendan;
- Ford, James;
- Alizadeh, Ash;
- Quake, Stephen;
- Kunz, Pamela;
- Beausang, John
Neuroendocrine tumors (NETs) arising from tailgut cysts are a rare but increasingly reported entity with gene expression profiles that may be indicative of the gastrointestinal cell of origin. We present a case report describing the unique pathological and genomic characteristics of a tailgut cyst NET that metastasized to liver. The histologic and immunohistochemical findings were consistent with a well-differentiated NET. Genomic testing indicates a germline frameshift in BRCA1 and a few somatic mutations of unknown significance. Transcriptomic analysis suggests an enteroendocrine L cell in the tailgut as a putative cell of origin. Genomic profiling of a rare NET and metastasis provides insight into its origin, development, and potential therapeutic options.