Breast metastasis as the first clinical manifestation of ileal neuroendocrine tumor. A challenging diagnosis with relevant clinical implications

leal neuroendocrine tumors are slow-growing grade 1 or, more rarely, grade 2 neuroendocrine tumors which, however, are frequently metastatic to regional lymph nodes and the liver. A few cases of ileal neuroendocrine tumors that are metastatic to the breast have also been reported in the medical literature. The knowledge of this uncommon clinical presentation is of great importance because it needs to be differentiated from primary breast carcinomas with neuroendocrine features, which represent completely different entities with a different therapeutic approach. The diagnosis of a breast metastasis from an ileal neuroendocrine tumor and its distinction from a well-differentiated primary neuroendocrine tumor of the breast is a challenging task for clinicians and pathologists. This workup is particularly difficult when the breast lesion is the first sign of malignancy. In the present paper, we describe the clinicopathological features of an ileal neuroendocrine tumor first presenting with a breast metastasis in a 50-year-old woman and we discuss the key diagnostic features for the differential diagnosis with primary well-differentiated neuroendocrine tumor of the breast. Moreover, we have reviewed the medical literature to give the reader a comprehensive overview on this topi

Neuroendocrine Neoplasms of the Gut

Neuroendocrine neoplasms of the gut are a heterogeneous group of tumors showing different morphological, clinical, prognostic, and molecular features. Currently, these proliferations are classified as “neuroendocrine neoplasms” (NENs), which include two main entities: well-differentiated neuroendocrine tumor (NET) and poorly differentiated neuroendocrine carcinoma (NEC). It is worth noting that a growing burden of evidence has been accumulating in the last years showing that NET and NEC, despite sharing neuroendocrine differentiation, are, in fact, two different diseases with different morphology, clinical presentation, outcome, and molecular background. NETs are graded with a three-tiered system (NET G1, NET G2, NET G3) based on the proliferation assessment, using both mitotic count and Ki67 proliferation index. NECs, which show a poorly differentiated morphology, are high grade by definition. In addition to pure NENs, mixed epithelial neoplasms composed of a neuroendocrine and a non-neuroendocrine component can be found in the digestive system. When each of the two components is malignant and reaches at least 30% of the tumor mass, these neoplasms are defined as mixed neuroendocrine–non-neuroendocrine neoplasms (MiNENs). There are different MiNEN types which show different morphology and prognosis mainly based on the clinicopathological characteristics of each component. While the global incidence of malignant neoplasms is more or less stable over the last 40 years, the incidence and prevalence of NENs has increased over the same period, probably reflecting the effectiveness of modern diagnostic tools with consequent frequent detection of early-stage cases. Due to the early detection and the use of more effective personalized therapeutic approaches, survival of patients with NETs has been improving over time

Rare diseases in clinical endocrinology: a taxonomic classification system

Rare endocrine-metabolic diseases (REMD) represent an important area in the field of medicine and pharmacology. The rare diseases of interest to endocrinologists involve all fields of endocrinology, including rare diseases of the pituitary, thyroid and adrenal glands, paraganglia, ovary and testis, disorders of bone and mineral metabolism, energy and lipid metabolism, water metabolism, and syndromes with possible involvement of multiple endocrine glands, and neuroendocrine tumors. Taking advantage of the constitution of a study group on REMD within the Italian Society of Endocrinology, consisting of basic and clinical scientists, a document on the taxonomy of REMD has been produced