Simultaneous multiple primary malignancies diagnosed by endoscopic ultrasound-guided fine-needle aspiration: A case report

BACKGROUND: Multiple primary malignancies (MPMs) refer to more than one primary malignancy in the same or separate organs of the same patient, and MPMs are considered when different histological characteristics are detected in epidemiological studies. Herein, we report a case presumed to be primary pancreatic cancer with multiple liver metastases by positron-emission tomography/computed tomography (PET/CT) and confirmed to be synchronous liver and pancreatic MPMs by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). CASE SUMMARY: A 50-year-old man was referred to our hospital due to abdominal discomfort for 2 mo. Abdominal CT at a local hospital revealed a pancreatic mass with multiple liver nodules. After being transferred to our hospital, PET/CT confirmed all these lesions to have elevated metabolic activity, and therefore primary pancreatic cancer with multiple liver metastases was considered. EUS-guided liver aspiration unexpectedly found signet-ring cells with a high Ki-67 positive rate (20%), while EUS-guided pancreatic aspiration detected pancreatic neuroendocrine cells with a relatively low Ki-67 positive rate (1%). The final diagnosis from the multidisciplinary team was simultaneous liver and pancreatic MPMs. The patient returned to his local hospital for neoadjuvant chemotherapy and surgery, and he is still alive during the 6-mo postoperative follow-up. CONCLUSION: Although rare, MPMs should be considered when treating pancreatic mass with suspected metastatic lesions, and EUS-FNA has proved minimally invasive and accurate.