Rare metastatic clear cell renal cell carcinoma to pancreas and duodenum revealed by EUS-guided fine-needle biopsy

A 60-year-old male patient was diagnosed with clear cell renal cell carcinoma (ccRCC) 10 years ago (Figure 1) and underwent radical right nephrectomy. The patient recently presented with melena lasting 1 month. Gastroscopy revealed a mucosal elevation in the descending duodenum with an erythematous surface. An adjacent suspicious accessory papilla with possible active bleeding was noted. Hemostasis was achieved using endoscopic clips, and no further melena occurred (Figure 2). Contrast-enhanced computed tomography of the upper abdomen showed a pancreatic head/uncinate process lesion potentially invading the descending and horizontal segments of the duodenum, along with multiple slightly enlarged mesenteric lymph nodes (Figure 3).

Figure 1.

Histological examination showed tumor tissue arranged in a nested pattern composed of polygonal cells with round nuclei. The stroma was congested, and the tumor had not breached the capsule.

Figure 2.

Gastroscopy revealed a mucosal elevation in the descending duodenum with erythematous surface. A, A suspected accessory nipple structure was visible near the lesion (black arrow). B, Active bleeding (black arrow). C, Hemostasis was achieved using endoscopic clips (black arrow).

Figure 3.

Contrast-enhanced CT revealed a lesion in the pancreatic head/uncinate process with suspected invasion of the descending and horizontal portions of the duodenum, accompanied by multiple mildly enlarged mesenteric lymph nodes (red arrow). CT, computed tomography.

To clarify the nature of the lesion, EUS-guided fine-needle biopsy (FNB) was performed and identified a 2.6 cm × 2.4 cm hypoechoic mass in the pancreatic uncinate process, with irregular but well-defined margins, heterogeneous internal echoes (Figure 4). Under real-time EUS guidance, the lesion was punctured twice using a 22G Acquire needle, with 20 back-and-forth movements under 15 mL negative pressure. Pancreatic biopsy (cell block) identified atypical cells (Figure 5). Pancreatic cytology (liquid-based) demonstrated malignant cells consistent with metastatic ccRCC (Figure 6). The final diagnosis was metastatic ccRCC to the pancreatic uncinate process presenting as duodenal bleeding.

Figure 4.

EUS showed a 2.6 cm × 2.4 cm hypoechoic mass in the pancreatic uncinate process with irregular but well-defined margins and heterogeneous internal echotexture.

Figure 5.

Pancreatic biopsy (cell block) acquired by EUS-FNB demonstrated atypical cells (red arrow).

Figure 6.

Pancreatic cytology (liquid-based preparation) revealed malignant cells consistent with metastatic ccRCC (red arrow).

Following multidisciplinary team discussion, the patient was deemed unsuitable for surgical resection because of duodenal involvement and potential systemic spread. Based on metastatic ccRCC, the patient was initiated on pembrolizumab immunotherapy. Follow-up imaging at three months showed stable disease without new metastatic lesions. Symptoms resolved completely following initial endoscopic hemostasis.

ccRCC has been observed to exhibit significant plasticity, with the most common sites of metastasis including the lungs, bones, liver, and brain.^[1] The occurrence of metastasis to the pancreas and duodenum is an infrequent phenomenon called isolated pancreatic metastases of renal cell carcinoma.^[2] Clinically and radiologically, such lesions may mimic primary pancreatic adenocarcinoma, yet their prognosis and management differ substantially.^[3] The present case illustrates metastatic ccRCC to the pancreas, causing duodenal bleeding. EUS-FNB was pivotal in establishing the correct diagnosis. Cytology and cell-block samples enabled comprehensive immunohistochemical profiling, confirming renal origin via classic markers (PAX-8, CD10, CA-IX) consistent with the patient’s primary tumor. Without tissue confirmation, the patient could have undergone extensive pancreatic surgery with no oncological benefit. EUS-FNB combined with immunohistochemistry provides a reliable method for distinguishing metastatic RCC from primary pancreatic tumors. This case underscores the critical role of EUS-FNB in evaluating pancreatic lesions in patients with a history of ccRCC, enabling accurate diagnosis and personalized management.

Source of Funding

This work was financially supported by the National Natural Science Foundation of China (Grants number 8217032680 and 82020108005).

Ethical Statements

The cased was studied in accordance with the Declaration of Helsinki. The patient in this article has given written informed consent to publication of their case details.

Conflicts of Interest

Zhendong Jin is an Associate Editor of the journal. The article was subjected to the standard procedures of the journal, with a review process independent of the editor and his research group. The other authors declare that they have no conflict of interest with regard to the content of this report.

Author Contributions

X. Tian, W. Du, and Y. Zhou: writing—original draft and data analysis. A. Li, Y. Wang, Z. Yang, and Z. Yang: data collection. D. Zhang, H. Huang, and Z. Jin: writing—review & editing.

Use of Large Language Models, AI, and Machine Learning Tools

None declared.

Data Availability Statements

Not applicable.