The new WHO classification of digestive neuroendocrine tumors

A new classification of digestive neuroendocrine neoplasms has been formulated in the 2010 revision of the WHO classification of digestive tumors. The principles of this new classification are different from those used in the previous one and the terminology is quite novel. Five main categories are recognized: neuroendocrine tumor G1; neuroendocrine tumor G2; neuroendocrine carcinoma, small cell type; neuroendocrine carcinoma, large cell type; mixed adenoneuroendocrine carcinoma (a new term for mixed tumors). This new classification will change the habits of the clinicians, familiar with the previous classification, which formed the basis for deciding the therapeutic strategy and the type of patient management. Attention must be paid when establishing the concordance between the new classification and the previous one and when reclassifying a previously diagnosed case, now under follow-up. Recommendations are proposed for the redaction of the pathological reports in this period of transition.