Diagnosis of Mixed Adenoneuroendocrine Carcinoma (MANEC) after Neoadjuvant Chemotherapy for Pancreatic and Gastric Adenocarcinoma: Two Case Reports and a Review of the Literature

Mixed neuroendocrine and adenocarcinoma of gastrointestinal tract: A complex diagnosis and therapeutic challenge

In this editorial we comment on the manuscript describing a case of adenocarcinoma mixed with a neuroendocrine carcinoma of the gastroesophageal junction. Mixed neuroendocrine and non-neuroendocrine neoplasms of the gastrointestinal system are rare heterogeneous group of tumors characterized by a high malignant potential, rapid growth, and poor prognosis. Due to the rarity of these cancers, the standard therapy is poorly defined. The diagnosis of these tumors is based on combination of morphological features, immunohistochemical and neuroendocrine and epithelial cell markers. Both endocrine and epithelial cell components can act independently of each other and thus, careful grading of each component separately is required. These cancers are aggressive in nature and the potential of each component has paramount importance in the choice of treatment and response. Regardless of the organ of origin, these tumors portend poor prognosis with increased proportion of neuroendocrine component. Multidisciplinary services and strategies are required for the management of these mixed malignancies to provide the best oncological outcomes. The etiopathogenesis of these mixed tumors remains obscure but poses interesting question. We briefly discuss a few salient points in this editorial.

Gastric mixed neuroendocrine non-neuroendocrine neoplasms

The uncommon tumour known as gastric mixed neuroendocrine-non-neuroendocrine neoplasms (G-MiNENs) is made up of parts of neuroendocrine carcinoma and adenocarcinoma. The biological and clinical features are different from those of gastric adenocarcinoma. Their pathophysiology, diagnostic standards, and clinical behaviour have all been the subject of lengthy debates, and their nomenclature has undergone multiple changes. Its emergence has created new challenges in the classification and diagnosis of gastric tumours. This review will update information on the topic, covering molecular aspects, diagnostic criteria, treatment, and prognostic factor discovery. It will also provide a historical context that will aid in understanding the evolution of the idea and nomenclature of mixed gastric tumours. Additionally, it will provide the reader a thorough understanding of this difficult topic of cancer that is applicable to real-world situations.

Unexpected pancreatic mixed neuroendocrine-nonneuroendocrine neoplasms (MiNEN)-reflection on a case report

The authors present a case involving a 51-year-old male who was diagnosed with a 4-cm mass in the body of the pancreas, initially suspected to be a ductal adenocarcinoma due to an elevated Ca 19.9 during routine analysis. Subsequent imaging studies confirmed a resectable disease without suspicious lymph nodes or distant metastasis, leading to the proposal of surgery. The patient underwent a laparoscopic distal splenopancreatectomy, which was uneventful. The histopathological examination revealed a 3.7-cm pancreatic mixed neuroendocrine neoplasia (MiNEN) with a predominant high-grade ductal adenocarcinoma component and a concurrent high-grade neuroendocrine carcinoma, with negative margins. Two lymph node metastases were identified, each representing metastasis of one of the components. The tumor was classified as pT2N1M0. Currently, the patient is undergoing chemotherapy with FOLFIRINOX. This case prompts reflection on the optimal treatment strategy for pancreatic MiNEN and raises the question of how the preoperative diagnosis could influence the patient's outcome.

Advanced gastric cancer with metachronous intracranial oligometastases without recurrence after multidisciplinary team discussion and comprehensive treatment: a case report

This article describes the process of multidisciplinary team (MDT) discussion and comprehensive treatment of a case of advanced gastric cancer that tested positive for programmed death ligand 1 (PD-L1). During diagnosis, the patient presented with advanced gastric cancer and numerous unresectable metastases in the lesser omental lymph nodes, both lungs, liver, and left parietal occipital lobe. A meeting was arranged for the departments of oncology, gastrointestinal surgery, radiotherapy, imaging, and pathology to discuss the case. Initially, the patient had a partial response to the first-line treatment, which was a combination of pembrolizumab and chemotherapy. However, after nineteen months, the patient presented with a metachronous isolated lesion in the left frontal lobe. After mutual agreement among the oncology, brain surgery, gastrointestinal surgery, radiotherapy, imaging, and pathology departments, the intracranial lesion underwent resection. Following this, the operation was supplemented by stereotactic radiation therapy (SRT) and whole-brain radiation therapy (WBRT). The patient showed excellent signs of recovery after the operation, and her general condition remained favorable after 16 months of follow-up. Nonetheless, the outlook for patients facing advanced-stage gastric cancer remains distressing. Through multidisciplinary team (MDT) discussions, patients diagnosed with advanced gastric cancer can receive standardized diagnostic and treatment approaches to develop reasonable and personalized comprehensive treatment plans. Such plans help to improve the quality of life of patients and effectively prolong their survival time.

Incidence, survival, and prognostic factors for patients with gastrointestinal mixed neuroendocrine non-neuroendocrine neoplasms: a SEER population-based study

BACKGROUND

Mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs) are a group of rare tumors with limited research currently available. This study aimed to analyze the incidence, survival, and prognostic factors of gastrointestinal MiNENs.

METHODS

We included data from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2019. We compared the clinicopathologic characteristics and survival rates between MiNENs and neuroendocrine tumors (NETs), and calculated the incidence of MiNENs. We utilized univariate and multivariate Cox analysis to assess independent factors of prognosis and established a nomogram to predict 1-, 2-, and 3-year cancer-specific survival (CSS). Calibration and receiver operating characteristic (ROC) curves were drawn to validate the accuracy and reliability of the model. Decision curve analysis (DCA) was used to assess the clinical utility of the model.

RESULTS

Patients with gastrointestinal MiNENs had a poorer prognosis than those with NETs. The overall incidence of gastrointestinal MiNENs has been increasing annually. Multivariate Cox regression analysis revealed that tumor size, lymph node metastasis, distant metastasis, and surgery were independent risk factors for CSS in MiNENs patients. Based on these risk factors, the 1-, 2-, and 3-year CSS nomogram model for MiNENs patients was established. Calibration, ROC, and DCA curves of the training and validation sets demonstrated that this model had good accuracy and clinical utility.

CONCLUSION

Gastrointestinal MiNENs are rare tumors with an increasing incidence rate. The nomogram model is expected to be an effective tool for personalized prognosis prediction in MiNENs patients, which may benefit clinical decision-making.

Mixed Neuroendocrine-Non-Neuroendocrine Neoplasms of the Pancreas

Pancreatic mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are rare neoplasms, composed of at least two components. The neuroendocrine part is always present. Histology is the most important tool for the diagnosis, but in the case of MiNEN, it is also important for the use of immunohistochemistry, which should include neuroendocrine but also ductal and acinar markers. Each component should be specifically described in the final pathology report, including the percentage on the entire tumor mass. The prognosis of MiNEN is very heterogeneous and depends on the different tumor components.

Mixed neuroendocrine–nonneuroendocrine neoplasms of the gastrointestinal system: An update

Mixed neuroendocrine-nonneuroendocrine neoplasms (MiNENs) of the digestive tract are a rare heterogeneous group of tumors that present many challenges in terms of diagnosis and treatment. Over the years, the diagnostic criteria, classification, and clinical behavior of these tumors have been the subjects of ongoing debate, and the various changes in their nomenclature have strengthened the challenges associated with MiNENs. This review is performed to provide an understanding of the key factors involved in the evolution of the designation of these tumors as MiNEN, highlight the current diagnostic criteria, summarize the latest data on pathogenesis and provide information on available treatments. Moreover, this work seeks to increase the awareness about these rare neoplasms by presenting the clinicopathological features and prognostic factors that play important roles in their behavior and discussing their different regions of origin in the gastrointestinal system (GIS). Currently, the MiNEN category also includes tumors in the GIS with a nonneuroendocrine component and epithelial tumors other than adenocarcinoma, depending on the organ of origin. Diagnosis is based on the presence of both morphological components in more than 30% of the tumor. However, this value needs to be reconfirmed with further studies and may be a limiting factor in the diagnosis of MiNEN by biopsy. Furthermore, available clinicopathological data suggest that the inclusion of amphicrine tumors in the definition of MiNEN is not supportive and warrants further investigation. The diagnosis of these tumors is not solely based on immunohistochemical findings. They are not hybrid tumors and both components can act independently; thus, careful grading of each component separately is required. In addition to parameters such as the metastatic state of the tumor at the time of diagnosis and the feasibility of surgical resection, the aggressive potential of both components has paramount importance in the choice of treatment. Regardless of the organ of origin within the GIS, almost MiNENs are tumors with poor prognosis and are frequently encountered in the elderly and men. They are most frequently reported in the colorectum, where data from molecular studies indicate a monoclonal origin; however, further studies are required to provide additional support for this origin.

Neoadjuvant and Adjuvant Chemotherapeutic Strategy of Colorectal Mixed Adeno-Neuroendocrine Carcinomas

Mixed adeno-neuroendocrine carcinomas (MANEC) is a rare pathological diagnosis characterized by the presence of both adeno-carcinomatous and neuroendocrine differentiation with each component comprising 30% of the tumor. This literature review is aimed at the extraction of all existing clinical studies and reviews on colorectal MANEC so as to ensure that a suitable chemotherapeutic regimen is chosen to improve survival outcomes and prognosis of the disease. Parallel search strategies were employed to extract past 10 years articles from PubMed, PubMed Central and Google Scholar databases. A total of 30 records consisting of one clinical trial, five retrospective cohort studies, one case control study, one case series, 16 case reports and six review papers were shortlisted. Chemotherapeutic regimens that were administered as an adjuvant and a neoadjuvant therapy were analyzed with their survival outcomes. The overall survival rate of those administered with neoadjuvant and adjuvant therapy can be as high as 57.4% and 69%, respectively. Multiple chemotherapeutic regimens were employed in colorectal MANEC and superiority of one regimen over the other can’t be established. Any drug or combination of drugs that is responsive against either of the MANEC components is found to be effective against the tumor. However, excellent responsiveness has been found with 5-fluorouracil regimens as a neoadjuvant therapy and platinum-based combinations as an adjuvant therapy. XELOX, streptozocin and S1 regimens also prove to be drugs of choice in aggressive and metastasized disease conditions. Our analysis allows for improved chemotherapeutic management of individuals with colorectal MANEC and establishes an increased potential for use of streptozocin therapy in the clinical setting. However, newer drugs like amrubicin require further research prior to describing its efficacy in colorectal MANEC.

Clinicopathological features and prognostic factors associated with gastroenteropancreatic mixed neuroendocrine non-neuroendocrine neoplasms in Chinese patients

BACKGROUND

The incidence of mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) is low. To improve our understanding of this rare tumor type and optimally guide clinical treatment, associated risk factors, clinical manifestations, and prognosis must be explored.

AIM

To identify risk factors that influence the prognosis of patients with gastroenteropancreatic MiNEN (GEP-MiNEN).

METHODS

We retrospectively analyzed the clinical data of 46 patients who were diagnosed with GEP-MiNEN at the First Affiliated Hospital of Bengbu Medical College (Anhui, China) between January 2013 and December 2017. Risk factors influencing the prognosis of the patients were assessed using Kaplan-Meier curves and cox regression models. We compared the results with 55 randomly selected patients with gastroenteropancreatic GEP neuroendocrine tumors, 47 with neuroendocrine carcinomas (NEC), and 58 with poorly differentiated adenocarcinoma.

RESULTS

Among the 46 patients with GEP-MiNEN, thirty-five had gastric tumors, nine had intestinal tumors (four in the small intestine and five in the colon and rectum), and two had pancreatic tumors. The median age of the patients was 66 (41-84) years, and the male-to-female ratio was 2.83. Thirty-three (71.7%) patients had clinical stage III and IV cancers. Distant metastasis occurred in 14 patients, of which 13 had metastasis to the liver. The follow-up period was 11-72 mo, and the median overall survival was 30 mo. Ki-67 index ≥ 50%, high proportion of NEC, lymph node involvement, distant metastasis, and higher clinical stage were independent risk factors affecting the prognosis of patients with GEP-MiNEN. The median overall survival was shorter for patients with NEC than for those with MiNEN (14 mo vs 30 mo, P = 0.001), but did not significantly differ from those with poorly differentiated adenocarcinoma and MiNEN (30 mo vs 18 mo, P = 0.453).

CONCLUSION

A poor prognosis is associated with rare, aggressive GEP-MiNEN. Ki-67 index, tumor composition, lymph node involvement, distant metastasis, and clinical stage are important factors for patient prognosis.

Looking into digestive mixed neuroendocrine - nonneuroendocrine neoplasms: subtypes, prognosis, and predictive factors

Mixed neuroendocrine - nonneuroendocrine neoplasms (MiNENs) of the digestive system represent a challenge for both pathologists and clinicians. Their nomenclature has changed several times, and their diagnostic criteria, classification and clinical behaviour have been matter of debate over the years. Although several attempts have been made to elucidate the pathogenesis and biology of MiNENs, some issues remain open. This review will provide: a historical background that helps in understanding the evolution of the concept and nomenclature of mixed neoplasms; a revision of the knowledge on this topic, including molecular aspects, to give the reader a comprehensive and practical overview on this challenging field of pathology; a focus on the diagnostic criteria and on the determination of prognostic and predictive factors; and a description of the different tumour types in the different sites of origin.

Mixed adenoneuroendocrine carcinoma (MANEC) of the ampulla of Vater in a Chinese patient: A case report

Mixed adenoneuroendocrine carcinoma (MANEC) is a rare tumour of the gastrointestinal tract with both epithelial and neuroendocrine components. We describe a case of a 57-year-old man who presented with yellow sclera and dark urine. Contrast-enhanced computed tomography (CT) showed enlargement of the intra and extrahepatic bile ducts and a neoplastic lesion at the end of the common bile duct which was indistinguishable from the adjacent head of the pancreas and duodenum. A pancreaticoduodenectomy was performed and histopathological examination of resected samples showed that tumour was a complex lesion with adenocarcinoma and neuroendocrine components positive for neuroendocrine markers (chromogranin A and synaptophysin) with a Ki-67 labelling index of 40%. The patient was diagnosed with MANEC in the ampulla of Vater with a neuroendocrine carcinoma component of approximately 70%. Ampullary MANECs are highly aggressive tumours with a high risk for distant metastases and a poor prognosis. Therefore, establishing a standard therapeutic strategy is crucial.

Neoadjuvant chemotherapy improves the survival of patients with neuroendocrine carcinoma and mixed adenoneuroendocrine carcinoma of the stomach

PURPOSE

The impact of neoadjuvant chemotherapy (NAC) on patients with neuroendocrine carcinoma (NEC) and mixed adenoneuroendocrine carcinoma (MANEC) of the stomach is unclear. The aim of this retrospective study was to evaluate the effects of NAC on patients with these conditions.

METHODS

This study included patients with locally advanced NEC or MANEC of the stomach who underwent gastrectomy. Histologic and prognostic effects of NAC were assessed. The overall survival (OS) rate was used to compare treatment efficacies between NAC patients and surgery-first patients.

RESULTS

Of the 69 patients included in this study, 20 received NAC and 49 underwent surgery first after diagnosis. A total of 13 patients responded to NAC (including 3 with complete remission and 10 with partial remission) and 7 patients acquired stable disease status according to the Response Evaluation Criteria in Solid Tumors version 1.1. One patient (5%) achieved a pathological complete response after NAC. Pathological tumor regression grades 1, 2, 3, 4, and 5 were observed in 1 (5%), 5 (25%), 3 (15%), 10 (50%), and 1 (5%) patient(s) with NAC, respectively. The incidence of postoperative complications was similar in the two groups. Patients in the NAC group demonstrated better OS than did patients in the surgery-first group (P = 0.032). Multivariate analyses showed that NAC, adjuvant chemotherapy, and the clinical N stage were independent factors affecting OS.

CONCLUSION

In patients with locally advanced NEC and MANEC of the stomach, NAC significantly improved OS.