What Causes Desmoplastic Reaction in Small Intestinal Neuroendocrine Neoplasms?

PURPOSE OF REVIEW: Mesenteric desmoplasia in small intestinal neuroendocrine neoplasms (SINENs) is associated with increased morbidity and mortality. In this paper, we discuss the development of desmoplasia in SINENs. RECENT FINDINGS: The fibrotic reactions associated with these tumours could be limited to the loco-regional environment of the tumour and/or at distant sites. Mesenteric fibrotic mass forms around a local lymph node. Formation of desmoplasia is mediated by interactions between the neoplastic cells and its microenvironment via number of profibrotic mediators and signalling pathways. Profibrotic molecules that are mainly involved in the desmoplastic reaction include serotonin, TGFß (transforming growth factor ß) and CTGF (connective tissue growth factor), although there is some evidence to suggest that there are a number of other molecules involved in this process. Desmoplasia is a result of autocrine and paracrine effects of multiple molecules and signalling pathways. However, more research is needed to understand these mechanisms and to develop targeted therapy to minimise desmoplasia.

Duodenal neuroendocrine neoplasms with unexpectedly aggressive behaviour: Challenging the "watch and wait" approach.

The incidence of duodenal neuroendocrine neoplasms has risen over the past decades as a result of the wide availability of endoscopy and associated expertise. Although it is considered that tumour size greater than 10 mm, higher tumour grade and/or location in relation to the ampulla of Vater represent the main risk factors for local or distant metastases, we describe two cases of well differentiated grade 1 and grade 2 neuroendocrine tumours, which measured < 10 mm at the time of diagnosis but had an aggressive course during follow-up. Furthermore, we also summarise the available therapeutic strategies for the management of small, low grade, non-functioning, non-ampullary duodenal neuroendocrine neoplasms.

Middle ear neuroendocrine tumours: Insight into their pathogenesis, diagnosis and management.

Recent advances in the diagnosis of neuroendocrine tumours (NETs) have led to the identification of NETs in unusual locations. NETs originating in the middle ear have been reported in a number of case reports with differing terminologies, where they were variously referred to as middle ear adenomas or middle ear carcinoids. In this report, we describe two cases of middle ear NETs with locally advanced disease and with distant metastases, respectively. The embryological origin, pathogenesis and histopathological characteristics, including immunohistochemical markers, are discussed aiming to clarify the terminology of these tumours. Functional imaging modalities (eg, 68 Ga-DOTATATE positron emission tomography/computed tomography/magnetic resonance imaging) play a pivotal role in the diagnosis, staging and determining the optimal systemic therapy in managing NETs of the middle ear. In addition, surgical, local and systemic therapeutic modalities are discussed, including the management option of long-acting somatostatin analogue therapy and targeted radionuclide therapy for somatostatin receptor-positive well-differentiated middle ear NETs.