Author:
Cibulskaitė Gabrielė,Stulpinas Rokas,Poškus Eligijus,Tulytė Skaistė,Mickys Ugnius
Abstract
MiNEN (mixed neuroendocrine-non-neuroendocrine neoplasm) is described in the 5th edition WHO classification of tumors of the digestive system as a mixed neoplasm, composed of neuroendocrine and non-neuroendocrine parts, each accounting for at least 30% of the tumor. Recently this formal criterion has been criticized based on the theory that both of these components could have a monoclonal origin and non-neuroendocrine cells develop neuroendocrinicity in the later evolutionary steps of adenocarcinoma. For this reason, the identification of pure adenocarcinoma component, that was overgrown by a more aggressive clone with neuroendocrine features, in a pathological specimen can be difficult and, in some cases, even impossible. So, it is likely that at least some of large cell neuroendocrine carcinomas follow the same pathway, a theory that is further supported by adenocarcinoma-like molecular alterations in these tumors. Precise diagnosis (which means identifying and naming each tumor component regardless of its size) is essential for a personalized treatment strategy. We present an illustrative case of a rectal neoplasm that could be classified as a poorly differentiated neuroendocrine carcinoma, but exhibits morphological heterogeneity, mucin production and has a typical KRAS mutation pointing to adenocarcinomatous origin, which makes MiNEN a more accurate diagnosis. The article discusses the key points in classification, pathogenesis, and diagnostic approach to help effectively manage such neoplasms.
Subject
Industrial and Manufacturing Engineering,Metals and Alloys,Strategy and Management,Mechanical Engineering