large cell neuroendocrine carcinoma (Monarch Disease Ontology entry MONDO_0005057) is a usually aggressive carcinoma composed of large malignant cells which display neuroendocrine characteristics. It is characterized by the presence of high mitotic activity and necrotic changes. The vast majority of cases are positive for neuron-specific enolase. Representative examples include lung, breast, cervical, and thymic neuroendocrine carcinomas. Also known as: LCNEC, large cell NEC, large-cell neuroendocrine carcinoma.