S1691 Smoke but No Fire: A Case of Massive CA 19-9 Elevation From NSAID Use

Abstract

Introduction: Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly prescribed medication for pain and inflammation, but are a leading cause of drug-induced liver injury (DILI). What is not well documented is ibuprofen-induced elevated carbohydrate antigen (CA) 19-9, which raises concern for pancreatic cancer. This case demonstrates liver injury and markedly elevated CA 19-9 in the 1000s, which resolved with cessation of ibuprofen use in the setting of negative endoscopic ultrasound (EUS) with fine needle aspiration (FNA). Case Description/Methods: 45 year old male with no history of liver or biliary disease presented with painless jaundice. Status post hemorrhoidectomy with daily ibuprofen use (400mg, 8 tablets) for pain. New-onset upper extremity pruritus with 13 lbs. unintentional weight loss. Upon evaluation, patient had AST 217 U/L, ALT 157 U/L, alkaline phosphatase (ALP) 964 U/L, and bilirubin 13.6 mg/dL without leukocytosis, platelet dysfunction, coagulopathy, or systemic symptoms. Right upper quadrant ultrasound did not demonstrate any obstruction. Screening CA 19-9 of 1046 U/mL prompted diagnostic EUS-FNA of pancreas, which was normal. Interval liver function tests and CA 19-9 demonstrated marked downtrend with cessation of ibuprofen use—AST 25 U/L, ALT 21 U/L, ALP 152 U/L, bilirubin 2 mg/dL, and CA 19-9 84 U/mL. Discussion: NSAIDs-induced DILI has an estimated incidence of 1-23 cases per 100,000 patient-years. Ibuprofen makes up ∼10% of DILI cases in developed countries. Time to onset is 12 days. Serum CA 19-9 is the only validated tumor marker for pancreatic cancer, which has an annual incidence of 3.9 per 100,000. Higher CA 19-9 serum levels with cut off of 90 U/mL have a sensitivity of 86% and specificity of 39% for malignancy. Our patient had a CA 19-9 >1000 U/mL with weight loss, which required evaluation with EUS-FNA to rule out malignancy. Elevated CA 19-9 secondary to ibuprofen has only been noted on a single center retrospective study as a statistically significant incidence of 7.1% of 581 patients, p = 0.034 when compared to controls. However, the underlying mechanism has not been defined on literature review. Thus, this case is a rare presentation of elevated CA 19-9 secondary to ibuprofen instead of something more sinister as a pancreatic malignancy. Thorough evaluation is necessary to provide reassurance that this is a transient process that will resolve with cessation of the offending agent.Figure 1.: On non enhanced images pancreas appear enlarged and hypodense with irregular margins.