Diagnosis and Management of Duodenal Bulb Neuroendocrine Carcinoma with Liver Metastases: A Case Report and Literature Review

Summary

This case describes a rare duodenal bulb neuroendocrine carcinoma with liver metastases, highlighting its aggressive nature, diagnostic challenges, and poor response to standard chemotherapy.

Abstract

Duodenal bulb neuroendocrine carcinoma (NEC), a subtype of neuroendocrine neoplasms (NENs), is a rare, high-grade malignancy often presenting at an advanced stage. We report a 40-year-old male with epigastric pain and melena who underwent a stepwise diagnostic and therapeutic protocol. Upper gastrointestinal endoscopy identified a 3.5 × 3.0 cm ulcerative lesion in the duodenal bulb, from which multiple deep biopsies were obtained to minimize the risk of misclassification, underscoring an essential educational point for clinical practice. Histopathological examination demonstrated poorly differentiated NEC with intravascular tumor thrombi, and immunohistochemical staining confirmed neuroendocrine differentiation (CgA, Synaptophysin, CD56, CK7) with a Ki-67 index of approximately 70%. Contrast-enhanced computed tomography (CT) revealed synchronous hepatic and lymph node metastases, establishing advanced disease. Following multidisciplinary evaluation, the patient received systemic chemotherapy with etoposide and cisplatin, administered in four cycles under routine monitoring of hematologic and hepatic parameters. Despite treatment, repeat CT demonstrated progressive hepatic lesions, culminating in hepatic failure and death. This protocol not only highlights the reproducible diagnostic workflow-endoscopic biopsy, immunohistochemical profiling, and cross-sectional imaging-but also serves an educational role in reminding clinicians of the diagnostic pitfalls inherent in superficial sampling and the necessity of deep biopsies for accurate classification. The case illustrates both the methodological steps required for accurate classification of duodenal NEC and the limitations of current treatment strategies. Our report contributes to the scarce data on duodenal bulb NEC and emphasizes the importance of early recognition, systematic diagnostic procedures, and multidisciplinary management to guide future practice.

Introduction

Neuroendocrine neoplasms (NENs) are a diverse group of tumors arising from neuroendocrine cells dispersed throughout the body, primarily within the gastrointestinal tract, pancreas, and lungs¹. These tumors originate from amine precursor uptake and decarboxylation (APUD) cells, which possess both neural and endocrine characteristics, and are capable of secreting biologically active peptides and amines². Within this spectrum, NENs are categorized into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs), the latter representing the high-grade, aggressive subtype, with....

Protocol

This protocol was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. Ethical approval was obtained from the Ethics Committee of Hebei Provincial Hospital of Traditional Chinese Medicine. Written informed consent was obtained from the patient prior to diagnostic and therapeutic procedures. All procedures were part of routine clinical care, and no experimental intervention was performed.

1. Patient selection

1. Confirm that the patient is an adult (≥18 years) presenting with upper gastrointestinal bleeding manifested as melena and accompanied by epigastric pain.
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Results

Successful diagnostic endoscopy revealed a 3.5 × 3.0 cm ulcerative lesion in the posterior wall of the duodenal bulb with elevated, friable mucosa and active contact bleeding (Figure 1A). Histological examination of biopsy specimens confirmed a poorly differentiated neuroendocrine carcinoma with intravascular tumor thrombi. Immunohistochemical staining demonstrated positive expression of neuroendocrine markers, including Synaptophysin, Chromogranin A, CD56, and CK7, with a Ki-67 proliferatio.......

Discussion

Neuroendocrine carcinomas (NECs) of the duodenum are rare, accounting for less than 2% of all duodenal neoplasms, with the majority arising in the ampullary region⁶. NECs of the duodenal bulb are exceedingly uncommon and frequently diagnosed at an advanced stage. Due to their rapid progression, strong heterogeneity, and often asymptomatic early course, they pose significant diagnostic and therapeutic challenges. In this case, the patient presented with melena and vague epigastric discomfort, and t.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
10% Neutral Buffered Formalin	Solarbio Life Sciences	G2161	Used for tissue fixation (12–24 h at room temperature, ratio 1:10).
Aprepitant Capsules	Merck & Co., Inc.	NDC 0006-3069-32	Oral NK1 receptor antagonist for antiemetic prophylaxis.
Biopsy Forceps (single-use)	Olympus Co., Ltd.	FB-25K-1	Compatible with a 2.8-mm channel; used for deep biopsy sampling from lesion base and margins.
CD34 Antibody	HUABIO	ET1606-11	Endothelial marker (vascularity control).
CD56 Antibody	HUABIO	ET1702-43	Neural cell adhesion molecule marker.
Chromogranin A Antibody (CgA)	HUABIO	HA600016	Marker for neuroendocrine differentiation.
Cisplatin	Bristol Myers Squibb	4291401A1089_1_09	Platinum-based chemotherapeutic agent; used in combination with etoposide.
Citrate Buffer (pH 6.0)	Beyotime Biotechnology	P0081	Used for antigen retrieval (95 °C for 20 min).
Class II B2 Biological Safety Cabinet	Thermo Fisher Scientific	1300 Series A2	Used for preparation of cytotoxic drugs.
CT Scanner	Siemens Co., Ltd.	SOMATOM Force	Used for contrast-enhanced CT of abdomen and staging; identified hepatic and nodal metastases.
Cytokeratin 7 Antibody (CK7)	HUABIO	ET1611-59	Marker for epithelial origin confirmation.
Cytotoxic Waste Container (yellow-labeled)	Medline	DYND30280H	Used for hazardous drug disposal per WHO/OSHA guidelines.
DAB Chromogen Kit	DAKO (Agilent Technologies)	K3468	For chromogenic visualization during IHC.
Dexamethasone Injection	Tianjin Kingyork Group	H12092034	Antiemetic and anti-inflammatory premedication.
EnVision HRP-conjugated Secondary Antibody	DAKO (Agilent Technologies)	K4007	Used for IHC signal detection.
Etoposide	Pfizer	21-321	Topoisomerase II inhibitor; part of EP chemotherapy regimen.
Gastroscope	Olympus Co., Ltd.	GIF-H290	Used for diagnostic endoscopy of the duodenal bulb to visualize a 3.5 cm × 3.0 cm ulcerative lesion; multiple deep biopsies obtained.
Hematoxylin and Eosin Staining Kit	Solarbio Life Sciences	G1120	For general histopathological staining.
Hydrogen Peroxide (3%)	Sinopharm Chemical Reagent Co., Ltd.	10009218	Used to block endogenous peroxidase.
Ki-67 Antibody	HUABIO	EM1705-40	Used to determine tumor proliferation index.
MRI Scanner	GE Healthcare	Signa Explorer 1.5 T	Used for small hepatic lesion detection via diffusion-weighted imaging.
Nitrile Gloves (double)	Ansell Healthcare	92-600	Used for handling cytotoxic materials safely.
Nonionic Iodinated Contrast (Iopamidol 300 mg I/mL)	Bracco Imaging S.p.A.	113410	Intravenous contrast for CT (100 mL at 3 mL/s).
Ondansetron Injection	GlaxoSmithKline	57243-130-30	Antiemetic prophylaxis prior to chemotherapy.
Poly-L-lysine Coated Slides	Thermo Fisher Scientific	P0425	Used for mounting tissue sections prior to immunohistochemistry.
Rotary Microtome	Leica Biosystems	RM2235	Used for sectioning paraffin-embedded tissues into 3–4 μm slices.
Sodium Chloride Injection (0.9%)	China Otsuka Pharmaceutical Co., Ltd.	H20093895	Used as diluent for cisplatin and etoposide infusions.
Synaptophysin Antibody (Syn)	HUABIO	ET1606-56	Marker for neuroendocrine differentiation.
Xylene and Graded Alcohols	Sinopharm Chemical Reagent Co., Ltd.	10009217	Used for dehydration and clearing of slides.