A benign or malignant neoplasm arising from the epithelial cells of an endocrine organ. Representative examples include pituitary gland adenoma, pituitary gland carcinoma, thyroid gland carcinoma, carcinoid tumor, and neuroendocrine carcinoma. The disease is Monarch Disease Ontology entry MONDO_0002082 (endocrine gland neoplasm). Also known as: endocrine gland neoplasm (disease), endocrine gland tumor, endocrine gland tumour, endocrine neoplasm, endocrine system neoplasm, endocrine system tumor, endocrine system tumour, endocrine tumor.