A case of pancreatic metastasis arising from occult lung cancer

Abstract

A 57-year-old man was admitted with complaints of stiffness on the right clavicle. Imaging study revealed swelling of multiple lymph nodes and pancreatic mass, but there were no such findings in the lung. Endoscopic ultrasound-guided fine needle aspiration for mediastinum lymph node and pancreatic mass revealed a poorly differentiated adenocarcinoma. He was diagnosed of pancreatic cancer with multiple lymph node metastases. Chemoradiotherapy was conducted. Six months later, he suffered from cardiac tamponade and died. The autopsy revealed a small nodule of poorly differentiated adenocarcinoma in the lung that could not be pointed out by computed tomography. Immunohistochemistry showed that both tumors of the lung and pancreas were positive for thyroid transcription factor-1 and napsin A, which are specific markers of lung cancer. Final diagnosis was primary lung cancer with metastases to the pancreas and heart. Pancreatic metastasis from occult lung cancer is rare. Lung cancer must be suspected when carcinoma of unknown primary is detected, even in the absence of the image findings of the lung. Immunostaining is useful in determining the primary site; hence, obtaining the cancer tissue is important.