Neuroendocrine neoplasms in rare locations: Clinicopathological features and review of the literature

Abstract

Introduction:Neuroendocrine tumors (NETs) occur more often in lungs, gastrointestinal tract, or pancreas. Data about terminology and grading of NETs in rare locations are scarce and variable, and they have been reported mainly as case reports.Materials and Methods:We here describe our experience with NETs in unusual locations. We have reviewed all NETs diagnosed in our institution and summarized their clinicopathological features. We have also reviewed the literature and discussed the main characteristics of NETs in each site.Results:Two hundred and forty-three primary NETs were diagnosed. About 55.2% of patients were men and the mean age was 62 years. About 90.7% of NETs were located in lungs, gastrointestinal tract, or pancreas, and 50.8% of them were low-grade tumors. We identified 13 NETs in rare locations: breast, ovary, endometrium, vulva, uterine cervix, extrahepatic biliary tract, kidney, sinonasal tract, and thymus. Three additional tumors were diagnosed by the senior author in other institution. Patients were asymptomatic or presented with nonspecific symptoms. All NETs were treated with surgery and 31% of patients received adjuvant therapy. There were 10 Grade 3 (62.5%), 2 Grade 2 (12.5%), and 4 Grade 1 (25%) tumors. Mean follow-up was 72 months. About 60% of G3 tumors recurred or progressed. G2 tumors were located in breast, and both patients are stable. About 50% of G1 tumors recurred or progressed (both renal NETs).Conclusions:NETs in rare locations are heterogeneous, and their behavior does not seem to correlate absolutely with tumor grade. More studies are needed to clarify the role of proliferation rate in these tumors.

Primary renal neuroendocrine neoplasms: A systematic literature review, report of four local cases, and original survival analysis of 63 patients from a national registry 2012–2018

“…31 In symptomatic patients, abdominal pain is the most common presenting symptom, followed by haematuria, abdominal mass, and constitutional symptoms such as weight loss and fever. 1,[11][12][13][14]16,17,24,27,[30][31][32][33][37][38][39][40][41][42][43][44][45][46]48,49 Although multiple other series have also noted an increased incidence of renal NEN in the right kidney some with higher proportions than others, 14,21,32,35,36 there are several included studies reporting relatively similar rates in each kidney. 12,18,31,32…”

“…17,33,46,50 Systemic chemotherapy in the form of combination therapy using a platinum-based agent was favoured in general in stage IV NEC. 6,14,17,32,33,36,[44][45][46]50 Because of the rarity of renal NEN and lack of prospective and randomized control trials, there is no widespread consensus on other treatment strategies. Radiotherapy has only been used in a few cases either in the adjuvant setting for residual disease or for symptomatic metastases.…”

“…Radiotherapy has only been used in a few cases either in the adjuvant setting for residual disease or for symptomatic metastases. 1,6,13,14,44,48 In the series of McGarrah et al, 1 somatostatin analogues were the most used first-line systemic treatment with stable disease reported in four of nine patients, followed by everolimus as second-line therapy. 1 Amin et al 36 also report the use of systemic treatment with octreotide and everolimus in well differentiated tumours and chemotherapy in NEC.…”

Head to head: do neuroendocrine tumours in the breast truly exist?

“…Numerous papers have been published through the years describing NE breast tumours (Table 1). 13,20,30,32–69 There is variation in how these tumours were defined and diagnosed, with some equating invasive breast carcinoma with NE differentiation as NEN/NET while others conform to the recently endorsed terminology for NEN, 9 with only rare reports of ‘carcinoids’. NECs form a significant proportion of these publications.…”

Challenges in treatment of a patient suffering from neuroendocrine tumor G1 of the hilar bile duct: a case report

“…Neuroendocrine tumors (NETs) are originated from the neuroendocrine cell system and have a steadily increased incidence from 1.09/100000 in 1973 to 6.98/100000 in 2012 [ 1 , 2 ]. NETs mainly occur in gastrointestinal tract (45.2%), respiratory system (30.2%) and pancreas (15.3%) [ 3 ]. The incidence of extrahepatic biliary neuroendocrine tumors (EBNETs) is extremely low and only accounts for 0.2–2% of all gastrointestinal NETs [ 4 ].…”