A narrative review in Histopathology sets out how gastrointestinal mixed neuroendocrine-non-neuroendocrine neoplasia (MiNEN) is defined under the 2026 WHO classification. It remains a tumour with two morphologically recognisable components, each making up at least 30% of the neoplasm, with clear neuroendocrine marker expression in the neuroendocrine component.
A non-neuroendocrine component that is only a precursor or an intramucosal lesion does not qualify. The review's example is that a neuroendocrine carcinoma arising from an adenoma should be reported as such, rather than as a mixed adenoma-neuroendocrine carcinoma or a MANET.
The sixth WHO edition adds amphicrine-like carcinoma, where neuroendocrine and non-neuroendocrine differentiation are intimately intermixed rather than in separate zones. Both groups are families of tumours rather than single diagnoses and need immunohistochemistry for confirmation. Molecular data support a common clonal origin rather than collision.
- MiNEN needs two recognisable components, each at least 30% of the tumour.
- A precursor or intramucosal non-neuroendocrine component does not make a MiNEN.
- Report a carcinoma arising from an adenoma by that description, not as MiNEN or MANET.
- Amphicrine-like carcinoma describes intermixed differentiation, not separate zones.
- Confirm both with immunohistochemistry.
Why it matters
Terminology that clinicians and registries rely on is being narrowed, so older reports using looser labels may not map to the current categories.
Don't overread it
This is a narrative review of the classification, not a study of outcomes, and it does not show that the terms predict treatment response.
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