Correlation of metastasis characteristics with prognosis in gastric mixed adenoneuroendocrine carcinoma: Two case reports

Oligometastatic Mixed Neuroendocrine Adenocarcinoma of the Esophago-Gastric Junction: A Case of Successful Multidisciplinary Management, the Lessons Learnt and Review of the Literature

Background: Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) of the esophago-gastric junction (EGJ) are rare aggressive malignant neoplasms, with, currently, limited evidence regarding the appropriate therapeutic approach. Methods: Herein, we report multimodal treatment management of a patient with oligometastatic MiNEN of EGJ (Siewert III), discuss the lessons learnt, and provide a review of the literature. Results: A 69-year-old female was diagnosed with a locally advanced EGJ tumor and three liver metastases (cT4, cN+, M1). Although the initial histology from biopsy revealed adenocarcinoma, the histopathology of a lymph node biopsy from staging laparoscopy revealed infiltration of neuroendocrine carcinoma cells. Thus, the diagnosis of a mixed neuroendocrine adenocarcinoma was set, and systemic chemotherapy with etoposide and cisplatin was initiated. A major clinical response led to conversion surgical resection of the primary tumor and metastases, followed by adjuvant therapy with immunotherapy. The patient is free of disease at the 3-year follow-up. A review of the literature on similar cases of EGJ or gastric MiNENs revealed a limited number of cases. Out of the 39 patients, 20 of them (51.3%) suffered from advanced-stage disease. The MiNEN diagnosis typically occurred after surgical resection. Systemic chemotherapy against the neuroendocrine component demonstrated significant response rates, while in cases in which conversion surgery was offered, prolongation of survival was demonstrated. Conclusions: Our case and the existing literature on MiNENs of EGJ underline the need for a personalized treatment approach following thorough interpretation of comprehensive pretherapeutic staging. Conversion radical surgery with curative intent could be considered in cases of major or complete clinical response to induction chemotherapy with potentially favorable outcomes.

Management and outcomes of mixed adenoneuroendocrine carcinoma of the ampulla of Vater: A systematic review and pooled analysis of 56 patients

BACKGROUND

Tumors of mixed neuroendocrine and nonneuroendocrine histology are classified as collision, combined, or amphicrine and can occur in most organs, including the hepato-pancreato-biliary tract. Given the rarity of mixed adenoneuroendocrine carcinoma (MANEC) of the ampulla of Vater, the patient characteristics, management, and outcomes remain unclear. We sought to systematically review the worldwide literature on ampullary MANECs.

METHODS

Eligible studies were identified through a systematic search of the MEDLINE (via PubMed), Scopus, and Cochrane Library databases (end-of-search-date: January 5th, 2022), according to the PRISMA 2020 statement.

RESULTS

A total of 39 studies reporting on 56 patients with ampullary MANEC were included. The median age was 63.0 (interquartile range [IQR]: 51.0-69.0) years and 55.6% were male (n = 25/45). Most had combined tumors (64.4%; n = 29/45), followed by collision (24.4%; n = 11/45), and amphicrine tumors (11.1%; n = 5/45). More than half had lymph node metastasis (56.8%; n = 25/44), yet only 7.9% had distant metastasis (n = 3/38). Tumor resection (i.e., mostly pancreaticoduodenectomy) was performed in 96.3% (n = 52/54), followed by adjuvant chemotherapy in 61.8% (n = 21/34). Nearly half experienced disease recurrence (47.2%; n = 17/36) over a median follow-up of 12.0 (IQR: 3.0-16.0) months, and 42.1% (n = 16/38) died over a median follow-up of 12.0 (IQR: 4.0-18.0) months. The most common cause of death was disease progression/recurrence in 81.3% (n = 13/16).

CONCLUSION

Early diagnosis and management of ampullary MANEC is challenging yet crucial to improve outcomes since many patients are diagnosed at an advanced disease stage and have unfavorable outcomes. Multicenter granular data are warranted to further understand and improve outcomes in these patients.

GNEN-1: a spontaneously immortalized cell line from gastric neuroendocrine neoplasia

Mixed neuroendocrine-non-neuroendocrine neoplasms (MINEN) are rare tumors that consist of at least 30% of both neuroendocrine and non-neuroendocrine components. The data concerning the pathogenesis of MINEN suggest a monoclonal origin. We describe a spontaneously immortalized cell line derived from gastric MINEN called GNEN-1. Primary tumor consisted of components of high-grade neuroendocrine carcinoma and adenocarcinoma. The GNEN-1 cell line was initiated from metastatic tumor cells of peritoneal fluid and expresses a purely neuroendocrine phenotype. The GNEN-1 cell line grows as monolayers and has retained the neuroendocrine phenotype with positivity for chromogranin A in immunohistochemistry. Electron microscopy showed cytoplasmic dense core granules and axon hillocks. The karyotype revealed alterations typical of both adenocarcinoma and neuroendocrine carcinoma such as trisomy 7 and 8. GNEN-1 cells were also positive for stanniocalcin-1, a marker of poor prognosis in gastric carcinomas. Expression of several markers related to neuroendocrine tumors was found. There have been only a few studies on the pathogenesis of MINEN and management of the disease due to the rarity of this tumor type. Here we describe for the first time an immortalized cell line derived from mixed gastric NEN. The GNEN-1 line offers a tool for future research on gastric NEN.

Endoscopic findings of gastric mixed adenoneuroendocrine carcinoma: A case report

RATIONALE

Gastric mixed adenoneuroendocrine carcinoma (gMANEC) is a rare malignant tumor. Most gMANECs are diagnosed at an advanced stage and have a worse prognosis than gastric adenocarcinoma. In order to improve the prognosis, it is necessary to diagnose gMANEC at an early stage. However, the endoscopic features of early gMANECs are unclear. We, herein, report a case of early gMANEC that showed characteristic magnifying endoscopic findings.

PATIENT CONCERNS

A 78-year-old man was referred to our institution for endoscopic resection of a gastric lesion. He had a medical history of distal gastrectomy due to early gastric cancer with negative surgical margins 9 years previously.

DIAGNOSIS

Esophagogastroduodenoscopy showed a reddish depressed lesion on the suture line of the gastric remnant, which was classified as type 0-IIc according to the Paris classification. ME-NBI at the oral side of the lesion revealed the absence of the microsurface pattern (MSP) and scattered microvessels with dilation and caliber variation, while ME-NBI at the anal side showed an irregularly tubular MSP. An endoscopic forceps biopsy showed a well- to moderately differentiated adenocarcinoma.

INTERVENTIONS

We performed endoscopic submucosal dissection, and en bloc resection of the tumor was successfully achieved.

OUTCOMES

The histological findings showed two distinct components: neuroendocrine carcinoma (NEC) and well-differentiated adenocarcinoma, which comprised ∼60% and 40% of the tumor, respectively. The NEC component corresponded to the site with the absence of an MSP and scattered microvessels on ME-NBI, while the well-differentiated adenocarcinoma component corresponded to the site with an irregularly tubular MSP. The pathological diagnosis was mixed adenoneuroendocrine carcinoma, infiltrating into the deep submucosal layer.

LESSONS

We propose that the absence of an MSP plus an irregular MSP is characteristics of gMANEC, which was useful for the diagnosis of gMANEC before treatment.

Adenocarcinoma and Neuroendocrine Collision Tumor in a Giant Gastric Hyperplastic Polyp

Screening esophagogastroduodenoscopy of a 65-year-old man revealed a 4.7-cm polypoid in the gastric high body. Clinical and laboratory findings, including serum gastrin level (460 pg/mL) and biopsy findings, were consistent with a diagnosis of type I neuroendocrine tumor (NET). Histologically, the mass consisted of dilated tortuous glands at the surface and grade 1 NET in deeper tissue. Some hyperplastic glands exhibited a transition to adenocarcinoma, which invaded the NET, simulating a "tumor in tumor" appearance. Next-generation sequencing revealed that the adenocarcinoma component harbored a TP53 mutation, whereas the NET component showed no pathogenic mutation. To our knowledge, this unusual collision of adenocarcinoma and NET within a single gastric hyperplastic polyp has not been previously described. This case suggests that large gastric hyperplastic polyps should be carefully examined because of the possibility of underlying NET and malignant transformation of surface epithelium.

Mixed Neuroendocrine Non-Neuroendocrine Neoplasms: A Systematic Review of a Controversial and Underestimated Diagnosis

Mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs) represent a rare diagnosis of the gastro-entero-pancreatic tract. Evidence from the current literature regarding their epidemiology, biology, and management is of variable quality and conflicting. Based on available data, the MiNEN has an aggressive biological behaviour, mostly driven by its (often high-grade) neuroendocrine component, and a dismal prognosis. In most cases, the non-neuroendocrine component is of adenocarcinoma histology. Due to limitations in diagnostic methods and poor awareness within the scientific community, the incidence of MiNENs may be underestimated. In the absence of data from clinical trials, MiNENs are commonly treated according to the standard of care for pure neuroendocrine carcinomas or adenocarcinomas from the same sites of origin, based on the assumption of a biological similarity to their pure counterparts. However, little is known about the molecular aberrations of MiNENs, and their pathogenesis remains controversial; molecular/genetic studies conducted so far point towards a common monoclonal origin of the two components. In addition, mutations in tumour-associated genes, including TP53, BRAF, and KRAS, and microsatellite instability have emerged as potential drivers of MiNENs. This systematic review (91 full manuscripts or abstracts in English language) summarises the current reported literature on clinical, pathological, survival, and molecular/genetic data on MiNENs.

Mixed adenoneuroendocrine carcinoma of the liver: A rare case report

A 55-year-old woman presented with chest and back pain of unknown cause. Contrast-enhanced computed tomography revealed two low-density tumors, sized 4.6 and 4.4 cm, in the hepatic caudate and left inner lobes, respectively. There are multiple enlarged lymph nodes around the abdominal aorta, hepatogastric ligament and gastrosplenic ligament. At the same time, there were multiple enlarged lymph nodes between the portal vein and the vena cava. Upper gastrointestinal endoscopy revealed chronic non-atrophic gastritis and esophagitis (grade B). Endoscopic examination of the lower digestive tract revealed polyps of the colon, diagnosed as tubular adenomas following biopsy and histopathological examination. The patient underwent left three hepatic resection (including left inner lobe, left outer lobe and right anterior lobe resection), abdominal lymph node dissection, right liver tumor radiofrequency ablation, hepatic caudate lobe resection, intestinal adhesion release, vena cava formation, portal vein repair and hilar cholangioplasty. The pathological examination of the resected specimens revealed intrahepatic bile duct carcinoma and hepatic parenchymal neuroendocrine tumor (NET). In addition, liver solid portions consisted of tumor cells with characteristic salt-and-pepper nuclei. Immunohistochemical examination revealed expression of the neuroendocrine marker synaptophysin in this solid component, confirming the diagnosis of NET. Furthermore, the MIB-1 proliferation index of the NET was higher compared with that of the adenocarcinoma, and lymph node invasion by the NET component was detected, indicating a neuroendocrine carcinoma (NEC, or NET G3). The diagnosis of mixed adenoneuroendocrine carcinoma of the liver was confirmed based on the World Health Organization 2010 criteria. Taking into consideration the patient's poor general condition, only symptomatic supportive treatment was administered postoperatively, without chemotherapy. Contrast-enhanced computed tomography at 45 days postoperatively revealed disease progression, with metastases in the liver stump, abdominal lymph nodes, spine and pelvis. The patient remained on symptomatic supportive treatment and succumbed to disease progression 3 months after surgery.

Efficacy of XELOX adjuvant chemotherapy for gastric mixed adenoneuroendocrine carcinoma: A case report

RATIONALE

Mixed adenoneuroendocrine carcinoma (MANEC) is a rare neoplasm, and consensus on the treatment is unavailable.

PATIENT CONCERN

A 60-year-old Chinese man presented with obstructive symptoms while eating and paroxysmal stomach pain for more than a month.

DIAGNOSIS

MANEC was diagnosed based on clinical manifestations, imaging findings, and pathological examinations.

INTERVENTIONS

The patient underwent radical gastrectomy and received XELOX adjuvant chemotherapy (oxaliplatin 200 mg day 1 + capecitabine 1.5 g twice a day) after surgery.

OUTCOMES

After 4 cycles of XELOX adjuvant chemotherapy were administered, abdominal computerized tomography and liver magnetic resonance showed liver metastasis.

LESSONS

The therapy of gastric MANEC is based on surgical operation, and adjuvant chemotherapy program has an important influence on its prognosis. Therefore, further studying the effectiveness of XELOX adjuvant chemotherapy for gastric MANEC is necessary.

Α-fetoprotein producing hepatoid gastric adenocarcinoma with neuroendocrine differentiation: A case report

RATIONALE

Hepatoid gastric adenocarcinoma is a rare type of gastric cancer. The phenomenon of neuroendocrine differentiation (NED) in gastrointestinal tumor needs further research. Both hepatoid adenocarcinoma and neuroendocrine differentiation are the factors leading to a poor prognosis of gastric cancer. However, there is still no specific treatment.

PATIENT CONCERNS

A 60-year-old man who had a pain and distention in his upper abdomen presented melena. Gastroscopy and pathology revealed a gastric cancer.

DIAGNOSES

Postoperative pathology revealed a hepatoid gastric adenocarcinoma. Immunohistochemical analysis showed a-fetoprotein (AFP), hepatocyte, synaptophysin (Syn), and chromogranin A (CgA) positive, and Ki67 60% positive. A-fetoprotein producing hepatoid gastric adenocarcinoma with NED is diagnosed.

INTERVENTIONS

The patient was treated with an R2 radical gastrectomy, but refused chemotherapy.

OUTCOMES

The AFP level was >2000 ng/mL (0-8.78) half a year after the surgery. There was no obvious abnormality from computed tomography (CT). The patient refused positron emission tomography computed tomography (PET-CT) and left the hospital.

LESSONS

Hepatoid adenocarcinoma and neuroendocrine differentiation are the factors leading to a poor prognosis of gastric cancer. It relapses easily. Long-term follow-up and regular examinations are necessary to detect relapses.