S3320 A Rare Case of Metastatic Pancreatic Neuroendocrine Tumor (PNET) in a Young Man

Abstract

INTRODUCTION: Pancreatic cancers are very aggressive cancers with high metastasizing potential. Pancreatic neuroendocrine tumors (PNETs) are rare cancers that account for 1-2% of pancreatic tumors. We present an unusual case of metastatic PNET occurring in a 32-year-old man. CASE DESCRIPTION/METHODS: A 32-year-old male without past medical history presented with worsening diffuse abdominal pain and nausea for 3 weeks. He also reported clay-colored stool, intermittent diarrhea, and stabbing abdominal pain. Labs showed total bilirubin 3.1 (0.3-1.2), direct bilirubin 2.2 (0-0.3), alk phos 173 (50-136), AST 124 (15-40), ALT 200 (4-47), and lipase 707 (59-393). Hepatomegaly was noted on the physical exam. Abdominal US demonstrated hepatomegaly with multiple isoechoic hepatic masses. CT A and P showed pancreatic body neoplasm with diffuse hepatic metastasis. Ca-19 and CEA tumor markers were within normal limits. Endoscopic US revealed an irregular pancreatic body mass measuring 30 mm × 25 mm. FNA showed high-grade neuroendocrine carcinoma with small cell features. FNA malignant cells were positive for CD56, Claudin4, pankeratin, with high proliferative activity (Ki-67 proliferation index is 60%). The patient was diagnosed with metastatic Stage 4 pancreatic cancer. The patient was discharged and later admitted to a different hospital with intractable abdominal pain and worsening jaundice. MRI of the pancreas showed 3.6 cm × 2.9 cm primary pancreatic neoplasm and innumerable hepatic metastasis replacing x >50% of the liver parenchyma. US-guided FNA of hepatic metastasis revealed small cell carcinoma with the Ki67 proliferation index greater than 90%. The tumor was positive for pancytokeratin (AE1/AE3), epithelial membrane antigen, synaptophysin, and CD56. Few tumor cells were positive for GI markers CDX2 and SATB2. Unfortunately, the patient was not a candidate for any intervention, and he was discharged to continue palliative chemotherapy at home. DISCUSSION: PNETs are malignant tumors with an insidious presentation. PNETs have a varied clinical manifestation, including abdominal pain, nausea, jaundice, and anorexia. Unfortunately, as demonstrated in this patient, pancreatic cancers often present with non-specific early symptoms and are identified at advanced stages with multiple metastases. Treating metastatic pancreatic cancer, especially in a young man, is challenging as the mainstay of treatment remains palliative.Figure 1.: PNET with diffuse hepatic metastasis on CT abdomen and pelvis.Figure 2.: PNET with diffuse hepatic metastasis on CT abdomen and pelvis.