1307 A Rare Case of Metastatic Adenocarcinoma to the Pancreas Secondary to a Primary Lung Malignancy

Abstract

INTRODUCTION: Metastatic pancreatic tumors are an infrequent occurrence. Pancreatic metastasis from non-small-cell lung cancer (NSCLC) is rare and might present with few symptoms when the tumor is small. Here, we report such an occurrence of metastatic pancreatic adenocarcinoma secondary to primary lung malignancy. CASE DESCRIPTION/METHODS: A 62-year-old male presented with cough, shortness of breath, early satiety and abdominal pain for a few days. His medical history was notable for hypertension, congestive heart failure, emphysema, and heavy cigarette use. He was hemodynamically stable on presentation. Initial labs were pertinent for NT-proBNP 969 pg/ml, low white blood cells 3.5 K/uL, low hemoglobin 11.7 gm/dL, elevated lipase 566 units/L, and elevated INR 3.2. Chest X-ray showed left basilar consolidation with pleural effusion. CT chest/abdomen/pelvis revealed 3 cm × 4 cm × 5 cm lower lobe consolidation in left lung (Figure 1), 2 cm × 2 cm × 2 cm low-attenuation lesion in pancreatic head, and multiple sclerotic lesions of thoracolumbar spine. Preliminary infectious workup was negative. He was started on empiric antibiotics for community-acquired pneumonia. Further testing for malignancy revealed a normal level of CA19-9 22.9 IU/ml, CEA 1.3 ng/ml, and PSA 0.83 ng/ml. He underwent upper endoscopic ultrasound (EUS) which showed 28 mm × 25 mm hypoechoic mass in the pancreatic head (Figure 2). The preliminary diagnosis was consistent with “adenocarcinoma”. Further immunostaining analysis of pancreatic mass was positive for TTF1 (Figure 3) and PD-L1, negative for p63 and CK5/6 compatible with primary lung adenocarcinoma. The lung mass was not biopsied in view of the presumptive diagnosis - primary lung adenocarcinoma with secondary metastasis to pancreas. After discharge, he was due to follow up in the Oncology clinic for more definitive treatment. DISCUSSION: There have been only a few reported cases of pancreatic metastases in the setting of primary lung malignancy. Among the subtypes of lung malignancy, pancreatic involvement is more common in small cell carcinoma whereas it is much less common in adenocarcinoma. Clinical presentation may range from asymptomatic to acute pancreatitis. EUS guided FNA and immunostaining studies tend to be the diagnostic tool of choice to differentiate between primary and secondary tumors. Identification of pancreatic metastases is important as it confers poorer prognosis and worse survival.