INTRODUCTION: Adenosquamous carcinoma of the pancreas (ASCAP) is a rare subtype of pancreatic cancer with estimated incidence of 1% to 4% among all pancreatic cancers. We report a case of this infrequently encountered tumor. CASE DESCRIPTION/METHODS: An 80-year-old man with hypertension, hyperlipidemia, social drinking (2 drinks/week), and tobacco abuse (24 pack years) presented with epigastric pain radiating to the back. Abdominal CT scan showed inflammatory pancreatic changes that were consistent with acute pancreatitis. CA 19-9 at this time was 222. MRCP revealed hypointense calcifications at the pancreatic head and uncinate process with numerous peripancreatic pseudocysts (largest 2 cm), favoring a diagnosis of acute on chronic pancreatitis. He was treated conservatively, improved, and was discharged home. He presented two months later with worsening epigastric pain and a 17-pound weight loss. CA 19-9 was now increased to 725. Repeat MRCP demonstrated persistence of pseudocysts and new 0.9 mm stricture at the mid-CBD with dilation of proximal CBD to 11 mm. EUS with FNA showed a 13 × 20 mm solid lesion with cystic component in the pancreatic head, showing squamous cell carcinoma. EGD showed gastric stenosis at the pylorus, and prepyloric gastric biopsy had tumor cells positive for CK7, CDX2, D2-40 and ERG, consistent with invasive adenocarcinoma with lymphovascular invasion. Further review of pathology with mucicarmine stain showed that the pancreatic tumor had a small adenocarcinoma component with predominant squamous differentiation, concluding metastatic ASCAP as the final diagnosis. Given his age and diagnosis, the patient received hospice. He survived 37 days from the time of initial presentation. DISCUSSION: ASCAP is thought to develop from squamous metaplasia related to inflammation from chronic pancreatitis. Our patient's presentation was atypical showing radiologic changes of chronic pancreatitis despite only one prior episode of acute pancreatitis. The prognosis of ASCAP is worse compared to pancreatic adenocarcinoma (PDAC) with reported median survival of 7 months. Additionally, aside from the risk factors of smoking, older age, and male gender, also associated with the more common PDAC, no other specific risk factors exist for development of ASCAP. Given the rarity of this diagnosis and the rapid deterioration of our patient, further information on pathogenesis and serum markers of ASCAP is necessary for improved risk stratification and better treatments for this poorly understood entity.