Neuroendocrine carcinomas (carcinoid, atypical carcinoid, small cell carcinoma, and large cell neuroendocrine carcinoma): current concepts

Epidemiology of Large Bowel Carcinoid Tumors in the USA: A Population-Based National Study

BACKGROUND AND AIMS

Prior studies have shown that about 90% of all carcinoid tumors occur in the GI tract. However, epidemiological studies of these tumors have been limited by small sample size. Our aim was to obtain a more robust epidemiologic survey of large bowel carcinoids (LBC), using population-based data in order to more accurately identify risk factors for these tumors.

METHODS

We used a commercial database (Explorys Inc, Cleveland, OH) which includes electronic health record data from 26 major integrated US healthcare systems. We identified all patients aged 18 and older who were diagnosed with LBC, excluding appendiceal carcinoids, between 1999 and 2018 based on Systematized Nomenclature Of Medicine-Clinical Terms (SNOMED-CT) and evaluated the prevalence of LBC. We also performed univariate analysis to describe age-, race-, and gender-based distributions and to identify potential risk factors.

RESULTS

Of the 62,817,650 individuals in the database, 4530 were identified to have LBC with an overall prevalence of 7.21/100,000. Individuals with LBC were more likely to be elderly (age > 65) [OR 2.17, CI 2.05-2.31, p < 0.0001], smokers [OR 3.25; 95% CI 3.00-3.53, p < 0.0001], have a history of alcohol use [OR 3.75; 95% CI 3.52-3.99, p < 0.0001], diabetes mellitus (DM) [OR 4.42; 95% CI 4.14-4.72, p < 0.0001], obesity [OR 1.58; 95% CI 1.43-1.74, p < 0.0001], family history of cancer [OR 8.06; 95% CI 7.47-8.71, p < 0.0001], and personal history of ulcerative colitis [OR 6.93; 95% CI 5.55-8.64, p < 0.0001] or Crohn's disease [OR 6.45; 95% CI 5.24-7.95, p < 0.0001]. The prevalence of LBC was less among Caucasians compared to African-Americans [OR 0.57; 95% CI 0.53-0.61, p < 0.0001]. There was no statistically significant gender-based difference; men versus women [OR 1.02; 95% CI 0.96-1.08, p = 0.47]. The most common presenting symptoms included flushing, diarrhea, nausea, weight loss, and abdominal pain, while the most common GI associations included perforation, obstruction, hemorrhage, intussusception, and volvulus.

CONCLUSION

This is the largest epidemiological study evaluating the prevalence of LBC. We estimated the prevalence rate of LBC to be 7.21/100,000. The presence of significant risk factors with the clinical picture suspicious for a LBC should warrant thorough evaluation as these tumors can lead to life-threatening complications. Further studies are needed to better understand the mechanism of association between these risk factors and LBC.

What clinicians are asking pathologists when dealing with lung neuroendocrine neoplasms?

Lung neuroendocrine tumors (NET) are currently classified in resection specimens according to four histological categories, namely typical carcinoid (TC), atypical carcinoid (AC), large-cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCC). Diagnostic criteria have remained unchanged in the 2015 WHO classification, which has ratified the wide acceptance and popularity of such terminology in the pathologists׳ and clinicians׳ community. A unifying umbrella of NE morphology and differentiation has been recognized in lung NET, which has pushed to enter an unique box of invasive tumors along with diffuse idiopathic pulmonary NE cell hyperplasia (DIPNECH) as a pre-invasive lesion with a potential toward the development of carcinoids. However, uncertainties remain in the terminology of lung NET upon small samples, where Ki-67 antigen could play some role to avoid misdiagnosing carcinoids as high-grade NE tumors. Epidemiologic, clinical and genetic traits support a biological three-tier over a pathology four-tier model, according to which TC are low malignancy tumors, AC intermediate malignancy tumors and LCNEC/SCC high malignancy tumors with no significant differences in survival among them. Inconsistencies in diagnostic reproducibility, troubles in the therapy of AC and LCNEC, and limitations to histology within the same tumor category argue in favor of a global re-thinking of lung NET where a grading system could play a role. This review outlines three main key questions in the field of lung NET: (A) unbiased diagnoses, (B) the role of Ki-67 and tumor grading, and (C) management of predictive markers. Answers are still inconclusive, thus additional research is required to improve our understanding on lung NET.

Role of computed tomography angiography in detection and staging of small bowel carcinoid tumors

Small-bowel carcinoid tumors are the most common form (42%) of gastrointestinal carcinoids, which by themselves comprise 70% of neuroendocrine tumors. Although primary small bowel neoplasms are overall rare (3%-6% of all gastrointestinal neoplasms), carcinoids still represent the second most common (20%-30%) primary small-bowel malignancy after small bowel adenocarcinoma. Their imaging evaluation is often challenging. State-of-the-art high-resolution multiphasic computed tomography together with advanced postprocessing methods provides an excellent tool for their depiction. The manifold interactive parameter choices however require knowledge of when to use which technique. Here, we discuss the imaging appearance and evaluation of duodenal, jejunal and ileal carcinoid tumors, including the imaging features of the primary tumor, locoregional mesenteric nodal metastases, and distant metastatic disease. A protocol for optimal lesion detection is presented, including the use of computed tomography enterography, volume acquisition, computed tomography angiography and three-dimensional mapping. Imaging findings are illustrated with a series of challenging cases which illustrate the spectrum of possible disease in the small bowel and mesentery, the range of possible appearances in the bowel itself on multiphase data and extraluminal findings such as the desmoplastic reaction in mesentery and hypervascular liver metastases. Typical imaging pitfalls and pearls are illustrated.

[Epithelial neuroendocrine tumors of the upper respiratory tract: New entities, new perspectives]

Epithelial neuroendocrine tumors of the upper respiratory tract are rare and are classified as typical and atypical carcinoid versus small cell neuroendocrine carcinoma. Furthermore, a giant cell variant of neuroendocrine carcinoma is suggested corresponding to the bronchopulmonary system as well as a recently described subtype of oropharyngeal small cell neuroendocrine carcinoma associated with human papillomavirus. Many arguments relying on clinical as well as on molecular findings indicate that the distinction between carcinoid and poorly differentiated neuroendocrine carcinoma does not only reflect different degrees of differentiation of otherwise related tumors but indicates the existence of substantially different types of neoplasms.

Unraveling tumor grading and genomic landscape in lung neuroendocrine tumors

Currently, grading in lung neuroendocrine tumors (NETs) is inherently defined by the histological classification based on cell features, mitosis count, and necrosis, for which typical carcinoids (TC) are low-grade malignant tumors with long life expectation, atypical carcinoids (AC) intermediate-grade malignant tumors with more aggressive clinical behavior, and large cell NE carcinomas (LCNEC) and small cell lung carcinomas (SCLC) high-grade malignant tumors with dismal prognosis. While Ki-67 antigen labeling index, highlighting the proportion of proliferating tumor cells, has largely been used in digestive NETs for assessing prognosis and assisting therapy decisions, the same marker does not play an established role in the diagnosis, grading, and prognosis of lung NETs. Next generation sequencing techniques (NGS), thanks to their astonishing ability to process in a shorter timeframe up to billions of DNA strands, are radically revolutionizing our approach to diagnosis and therapy of tumors, including lung cancer. When applied to single genes, panels of genes, exome, or the whole genome by using either frozen or paraffin tissues, NGS techniques increase our understanding of cancer, thus realizing the bases of precision medicine. Data are emerging that TC and AC are mainly altered in chromatin remodeling genes, whereas LCNEC and SCLC are also mutated in cell cycle checkpoint and cell differentiation regulators. A common denominator to all lung NETs is a deregulation of cell proliferation, which represents a biological rationale for morphologic (mitoses and necrosis) and molecular (Ki-67 antigen) parameters to successfully serve as predictors of tumor behavior (i.e., identification of pathological entities with clinical correlation). It is envisaged that a novel grading system in lung NETs based on the combined assessment of mitoses, necrosis, and Ki-67 LI may offer a better stratification of prognostic classes, realizing a bridge between molecular alterations, morphological features, and clinical behavior.

Combined neuroendocrine carcinoma and adenocarcinoma in the stomach: A case report

Neuroendocrine carcinoma and adenocarcinoma existing in the stomach simultaneously is extremely rare. This report presents a 65-year-old male patient who was diagnosed with three types of malignant tumors in the stomach, neuroendocrine carcinoma (NEC), moderately differentiated adenocarcinoma and mucinous adenocarcinoma. In addition, the NEC and moderately differentiated adenocarcinoma existed in the same lesion and, therefore, was referred to as a mixed adenocarcinoma - NEC tumor. The patient underwent laparoscopic-assisted D2 radical total gastrectomy, Roux-en-Y esophagus-jejunum anastomosis and received FOLFOX chemotherapy for six cycles 3 weeks after surgery. Follow-up determined that the patient survived and was tumor-free 12 months after surgery. In conclusion, radical surgery combined with chemotherapy can effectively improve the prognosis of patients with these three specific tumor types simultaneously in the stomach.

Primary Atypical Carcinoid Tumour of the Sphenoid Sinus Rostrum

Primary carcinoid tumors of the nasal cavity and sinuses are exceedingly rare. An accurate histopathological diagnosis is crucial to optimal investigation and management. We present a case of a primary atypical carcinoid tumor arising from the sphenoid rostrum without evidence of associated carcinoid syndrome. This rare but important differential diagnosis of a nasal tumor is discussed and important unique management issues are highlighted.

Primary neuroendocrine carcinoma in oral cavity: two case reports and review of the literature

Neuroendocrine carcinoma (NEC) is a tumor that occurs in different locations, particularly the lungs and larynx. The oral cavity is a rare site for a primary NEC. This report describes 2 cases of primary NEC in the oral cavity. Case 1 occurred in the anterior mandibular gingiva in a 25-year-old woman and presented with a special histologic appearance. This patient showed no evidence of recurrence 13 months after marginal resection of the anterior mandible. Case 2 was a primary NEC with some foci of squamous cell differentiation arising in the right buccal region in a 38-year-old woman. This patient showed no evidence of disease 8 months after tumor resection and postoperative iodine-125 brachytherapy. To the best of the authors' knowledge, case 1 is the youngest patient with NEC reported in the oral cavity to date in the English-language literature, and case 2 is the first report of a primary NEC in the buccal region.

Gastrointestinal carcinoid: epidemiological and survival evidence from a large population-based study (n = 25 531)

BACKGROUND

Owing to its rarity, the published evidence on gastrointestinal (GI) carcinoid is often based on small series of patients or population-based studies regarding all neuroendocrine tumors. Here, we present a comprehensive epidemiological and survival analysis of the largest cohort of patients with GI carcinoid ever reported.

PATIENTS AND METHODS

Patients with histological diagnosis of GI carcinoid (n = 25 531) were identified from the Surveillance Epidemiology End Results (SEER) database (including 18 USA cancer registries and spanning the 1973-2009 time frame). Demographic and disease data were used for epidemiological and survival analyses.

RESULTS

The incidence of GI carcinoid is steadily increasing over the past three decades at a rate higher than any other cancer [annual percentage change (APC) = 4.4, 95% confidence interval (CI) 4.0-4.8]. These patients have a higher risk of further primary tumor (standardized incidence ratio, SIR = 1.15, 95% CI 1.10-1.21), but also a reduced risk of skin melanoma (SIR = 0.64, 95% CI 0.41-0.95). Despite the overall favorable prognosis (5-year disease-specific and relative survival rate: 91.3% and 87.4%, respectively), the mortality rate is increasing over time (APC = 3.5, 95% CI 3.0-4.0) and the 5-year survival rate of patients dying of GI carcinoid (28.5%), though better than that reported for GI cancers in general (8.4%), cannot be considered satisfactory. Finally, a nomogram is provided to predict patient survival on the basis of clinico-pathological factors independently associated with prognosis at multivariate analysis.

CONCLUSIONS

These findings can be clinically useful for the management of patients with GI carcinoid and eagerly prompt the continuous effort to develop more effective therapeutic strategies against this slow-growing but chemoresistant tumor.

CT and enhanced CT in diagnosis of gastrointestinal neuroendocrine carcinomas

OBJECTIVES

To enhance diagnosis of gastrointestinal neuroendocrine carcinomas using CT and contrast-enhanced CT images.

METHODS

A total of 44 patients with gastrointestinal neuroendocrine carcinomas, as confirmed by clinical pathology and immunohistochemistry in the Sixth Affiliated People's Hospital of Shanghai Jiao Tong University Shanghai China, were included in the study. CT and enhanced CT scanning were performed, and the resulting images were reviewed and analyzed.

RESULTS

Twenty-seven males and 17 females were enrolled. Gastrointestinal involvement included the following: 5 cases located in the middle or inferior segment of the esophagus; 5 in the gastric cardia, 15 in the body of stomach, 6 located in the gastric antrum; 5 located in the Vater papilla of the duodenum; and 8 located in the colon. Among the 44 cases 80%-90% of the lesions had homogeneous density. Totally 81.8% (36/44) cases demonstrated homogeneous enhancement in arterial phases, most of the cases (n = 33) moderately or obviously enhanced. Only 17.2% (8/44) cases appeared as heterogeneous enhancement. And 86.4% cases (n = 38) were further enhanced in the venous phase. The CT images also revealed some of the metastases. Some liver metastasis cases have obvious homogeneous enhancement.

CONCLUSIONS

CT and enhanced CT provide useful information regarding gastrointestinal neuroendocrine carcinomas' location, density, enhancement pattern, and some metastasis. These features are helpful to increase the diagnostic accuracy.

Large cell neuroendocrine carcinoma of the thymus: a two-case report

A large cell neuroendocrine carcinoma (LCNEC) of the thymus is a very rare malignant tumor that has a very poor prognosis. The detailed clinical features of LCNEC are still unknown, including the long term prognoses and the definitive modalities of the treatment for LCNEC of the thymus. We are reporting 2 cases of an enlarged LCNEC of the thymus, both of which were diagnosed and treated by surgical resection followed by postoperative adjuvant chemoradiation therapy. Although recurrences and metastases of the LCNEC were noticed 1 and 4 years postoperatively for each case, aggressive surgical resection and adjuvant chemoradiation therapy may be helpful for a patient's long term survival.

Sinonasal neuroendocrine carcinoma: impact of differentiation status on response and outcome

Background

The impact of tumor differentiation on the behavior and response of sinonasal neuroendocrine carcinoma is unknown.

Methods

We performed a retrospective review of the patients treated for neuroendocrine carcinoma (NEC) of the nasal cavity or paranasal sinuses from 1992 to 2008 at MDACC.

Results

The results of our study suggest that pathologic differentiation may not be a critical factor in the clinical management of patients with NEC of the sinonasal tract. This is in contrast to laryngeal and lung NEC for which pathological differentiation has traditionally guided clinical management.

Conclusion

Mutlimodality approach should be the cornerstone of treating sinonasal NEC regardless of their differentiation. Specifically, RT may provide durable local control for patients with moderately differentiated NEC if resection is not feasible or desirable, while surgical resection can benefit patients with chemo-resistant or radio-resistant disease.

A case of primary combined neuroendocrine carcinoma with squamous cell carcinoma in the upper gingiva

Neuroendocrine carcinoma is a rare neoplasm that occurs widely in various organs and tissues. The biological behavior of this tumor in the oral region remains poorly understood. We encountered an extremely rare case of combined neuroendocrine carcinoma with squamous cell carcinoma, occurring at the buccal gingiva in a 62-year-old woman. Left partial maxillectomy was performed. Histological examinations revealed solid nests with extensive necrosis and nuclear palisading at the periphery. The tumor also showed areas of stratified neoplastic squamous differentiation. Immunohistochemically, tumor nests stained positive for synaptophysin, chromogranin, N-CAM (CD56), and neuron-specific enolase. Strong positivity was seen for K14 and K17 in the squamous component and for K7 in the neuroendocrine component. Both components showed K19 staining. Cells with squamous differentiation and K14 staining occasionally expressed p63. The patient showed no evidence of disease as of 23 months postoperatively. Given the aggressive characteristics of neuroendocrine carcinoma, strict follow-up has been performed.

Tumor receptor imaging

Tumor receptors play an important role in carcinogenesis and tumor growth and have been some of the earliest targets for tumor-specific therapy, for example, the estrogen receptor in breast cancer. Knowledge of receptor expression is key for therapy directed at tumor receptors and traditionally has been obtained by assay of biopsy material. Tumor receptor imaging offers complementary information that includes evaluation of the entire tumor burden and characterization of the heterogeneity of tumor receptor expression. The nature of the ligand-receptor interaction poses a challenge for imaging--notably, the requirement for a low molecular concentration of the imaging probe to avoid saturating the receptor and increasing the background because of nonspecific uptake. For this reason, much of the work to date in tumor receptor imaging has been done with radionuclide probes. In this overview of tumor receptor imaging, aspects of receptor biochemistry and biology that underlie tumor receptor imaging are reviewed, with the estrogen-estrogen receptor system in breast cancer as an illustrative example. Examples of progress in radionuclide receptor imaging for 3 receptor systems--steroid receptors, somatostatin receptors, and growth factor receptors-are highlighted, and recent investigations of receptor imaging with other molecular imaging modalities are reviewed.