Atypical Gastric Lesion Revealing Underlying Pancreatic Cancer With Direct Invasion

Byeong Joo Jo

doi:10.7704/kjhugr.2025.0032

Case Report

The Korean Journal of Helicobacter and Upper Gastrointestinal Research 2025;25(3):288-291.

Published online: September 1, 2025

DOI: https://doi.org/10.7704/kjhugr.2025.0032

Atypical Gastric Lesion Revealing Underlying Pancreatic Cancer With Direct Invasion

Byeong Joo Jo

Department of Internal Medicine, Semyeong Christianity Hospital, Pohang, Korea

Corresponding author Byeong Joo Jo, MD Department of Internal Medicine, Semyeong Christianity Hospital, 351 Posco-daero, Nam-gu, Pohang 37816, Korea E-mail: jam1124@naver.com

Received May 12, 2025; Revised June 11, 2025; Accepted June 29, 2025;

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Atypical gastric lesions present diagnostic challenges, particularly when they mimic benign conditions. We report the case of a 76-year-old male who underwent esophagogastroduodenoscopy (EGD) during routine screening. The EGD revealed a 1-cm ulcerative lesion in the lesser curvature of the stomach. The initial endoscopic report simply described the lesion as a “gastric ulcer,” and the initial biopsy indicated a tubulovillous adenoma with low-grade dysplasia. However, follow-up endoscopy demonstrated an irregular, non-healing ulcer without a clean base, raising a strong possibility of deeper infiltration. A follow-up biopsy showed atypical findings, suggestive of malignancy, and prompting further evaluation. Abdominal computed tomography (CT) revealed a mass in the pancreatic body and tail that directly invaded the gastric wall, along with extensive peritoneal metastasis. Positron emission tomography-CT confirmed hypermetabolic activity in the pancreatic lesion. The final diagnosis was a pancreatic adenocarcinoma with gastric invasion. This case highlights the importance of correlating endoscopic findings with imaging and pathology findings, especially when endoscopic morphology appears atypical and inconsistent with biopsy results. Repeat evaluations and cross-sectional imaging may prevent unnecessary procedures and allow timely identification of extrinsic malignancies that present as primary gastric lesions.

Key words: Pancreatic neoplasms; Stomach neoplasms; Neoplasm invasiveness; Diagnosis, differential; Endoscopy

INTRODUCTION

Pancreatic cancer is among the most aggressive gastrointestinal malignancies, often diagnosed at an advanced stage. It has a high mortality rate due to late diagnosis [1]. Common metastatic sites include lymph nodes, liver, lungs, and peritoneum, with gastric involvement being exceedingly rare [2]. Differentiating between primary gastric lesions and secondary invasion by pancreatic cancer is clinically challenging, especially when endoscopic appearances mimic benign pathology [3]. Herein, we report a case in which pancreatic cancer initially presented with endoscopic features suggestive of a benign gastric adenoma.

CASE REPORT

A 76-year-old male underwent screening esophagogastroduodenoscopy, revealing a 1 cm ulcerative lesion (Fig. 1) on the lesser curvature of the stomach. The initial endoscopic report described the lesion merely as a gastric ulcer and two biopsy specimens were obtained which indicated tubulovillous adenoma with low-grade dysplasia.

He was referred to our department for further management. He reported mild abdominal fullness and had central obesity, but no abdominal tenderness or signs of peritoneal irritation were noted on physical examination.

Although the initial endoscopic report described the lesion simply as a gastric ulcer, its irregular margins and granular surface raised the possibility of early gastric cancer, and endoscopic submucosal dissection (ESD) was initially planned. Routine laboratory tests revealed no anemia (hemoglobin 14.2 g/dL), no hypoalbuminemia (albumin 3.7 g/dL), and normal liver and renal function. Tumor marker showed elevated carcinoembryonic antigen (CEA) at 23.0 ng/mL (normal <2.5 ng/mL), while alpha-fetoprotein and carbohydrate antigen 19-9 (CA 19-9) were within normal limits. Colonoscopy was performed to rule out colorectal neoplasia and confirmed only benign tubular adenomas.

A second-look endoscopy revealed an irregular, non-healing ulcer without a clean base. Notably, muscle fibers consistent with the muscularis propria layer were directly exposed at the ulcer base, raising strong concern for deep infiltration. Additional findings such as mucosal friability and spontaneous oozing further heightened suspicion of malignancy (Fig. 2), leading to cancellation of ESD.

Re-biopsy showed atypical findings such as irregular, infiltrative glands embedded in a desmoplastic stroma, cribriform architecture, nuclear pleomorphism, hyperchromasia, and loss of polarity—suggestive of malignancy (Fig. 3), prompting further evaluation. An abdominal CT was performed, revealing an ill-defined mass in the pancreatic body and tail (Fig. 4) with main pancreatic duct dilatation and direct invasion into the gastric wall. Additionally, massive ascites and peritoneal carcinomatosis were noted. Positron emission tomography-CT (PET-CT) confirmed hypermetabolic activity in the pancreatic lesion (Fig. 5) [4].

Ascitic fluid analysis demonstrated markedly elevated CEA levels, supporting peritoneal carcinomatosis [5]. The final diagnosis confirmed advanced pancreatic adenocarcinoma with direct gastric invasion. The patient declined chemotherapy and was referred to hospice care.

DISCUSSION

Although primary gastric lesions are more common, extrinsic malignancy should be considered when endoscopic findings and pathology are not concordant. In this case, the initial tissue sampling suggested a benign lesion, but the lesion’s morphology and progression raised suspicion. Pancreatic cancers involving the stomach tend to originate from the body or tail and spread via direct extension [6]. Clinically, such lesions can resemble primary gastric ulcers, making evaluation complex.

Tumor markers such as CA 19-9 may not be elevated in all pancreatic cancers; the extremely low CA 19-9 in this patient illustrates that tumor markers alone may not be reliable in excluding pancreatic cancer [7]. Radiological correlation using CT and PET-CT is therefore essential to detect extra-luminal disease [4].

This case supports the use of repeated endoscopic evaluation and imaging when discrepancies between clinical, endoscopic, and histologic findings exist. Biopsies of ulcerative lesions may occasionally miss submucosal or externally infiltrating tumors, especially those of extrinsic origin. This highlights the limitations of superficial tissue sampling and the potential value of advanced techniques such as endoscopic ultrasound-guided fine needle aspiration. 8,9

In conclusion, this case highlights the importance of considering extrinsic malignancy when encountering atypical gastric lesions that are discordant with biopsy findings. A multidisciplinary diagnostic approach that integrates endoscopic morphology, histopathological findings, and cross-sectional imaging is essential to prevent misdiagnosis and ensure timely management.

Notes

Availability of Data and Material

All data generated or analyzed during the study are included in this published article.

Conflicts of Interest

The author has no financial conflicts of interest.

Funding Statement

None

Acknowledgements

The author thanks the Department of Pathology, Semyeong Christianity Hospital, for their support.

Ethics Statement

The patient was deceased at the time of manuscript preparation, and informed consent could not be obtained. All identifying details have been fully anonymized in accordance with ethical standards.

Fig. 1.

Initial screening esophagogastroduodenoscopy. A 1-cm ulcerative lesion with whitish exudate and central depression is noted on the lesser curvature of the upper gastric body.

Fig. 2.

Detailed endoscopic view using cap-fitted endoscope. Central ulceration with surrounding erythema and friable mucosa. Second-look esophagogastroduodenoscopy reveals deeper ulceration with irregular borders and mucosal disruption suggestive of fistulization.

Fig. 3.

Histopathologic examination of the gastric biopsy specimen (H&E stain). A: Irregular infiltrating glands with desmoplastic stroma (×200). B: Densely packed, irregularly branching glandular structures (×200). C: Cribriform patterns of malignant glandular formation (×200). D: Tumor cells showing nuclear hyperchromasia, pleomorphism, and loss of polarity (×400).

Fig. 4.

Contrast-enhanced abdominal computed tomography. Axial view showing an ill-defined hypodense mass in the pancreatic body invading the lesser curvature of the stomach. Coronal view reveals extensive peritoneal carcinomatosis and ascites.

Fig. 5.

Positron emission tomography-computed tomography (PET-CT). Axial fused PET-CT images show intense fluorodeoxyglucose uptake in the pancreatic mass and multiple peritoneal foci.

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