P0165 - Biliary Intraductal Papillary Mucinous Neoplasm (IPMN-B) Associated With Actinomyces

Munish Ashat, MBBS¹, Joseph Brant, MD², Surbhi Dadwal, MBBS^1
1University of Iowa Hospitals & Clinics, Iowa City, IA; ²University of Iowa Hospitals & Clinics, North Liberty, IA

Introduction: IPMN-B is the biliary counterpart of pancreatic IPMN. This rare entity is precursor lesion to cholangiocarcinoma, primarily affecting middle-aged to elderly men. Hepatobiliary actinomycosis is extremely rare and has been documented presenting as a mimicker of malignancy, pancreatitis, and cholecystitis. We present a unique case of IPMN-B in a patient found to have intraductal biliary actinomyces.

Case Description/Methods: A 76-year-old male with a remote history of post-cholecystectomy choledocholithiasis treated with ERCP presented with cholangitis. The patient underwent ERCP revealing a large amount tissue debris that was identified as fragments of papillary low-grade dysplasia (LGD) consistent with IPMN-B on histology. Endoscopic ultrasound located a hypoechoic lesion in mid-bile duct, with a fine needle biopsy confirming similar histology. Subsequent ERCP with cholangioscopy was performed for surgical planning revealing villous mucosa with characteristic fish-egg appearance (Figure A) extending from biliary orifice to 1 cm below the hilum. Intraductal biopsies of the IPMN-B were repeated, again noting LGD along with detection of colonies of Actinomyces. The patient underwent resection of common hepatic duct and common bile duct with Roux-En-Y hepaticojejunostomy. Pathology revealed IPMN-B with extensive high-grade dysplasia (HGD) and LGD with positive distal and proximal margins. Due to sigificant comorbidities, the patient was placed on surveillance with MRCP and CA19-19 as it was felt that he would not tolerate Whipple and liver resection required to achieve clear margins.

Discussion: Our case is unique due to an extremely rare finding of biliary actinomyces, which typically mimics malignancy, but was uniquely associated with a malignant lesion in this instance. The significance of this finding is uncertain. IPMN-B presents with nonspecific symptoms, making accurate preoperative diagnosis challenging. Early diagnosis of IPMN-B is critical for curative surgery and to prevent progression to invasive cholangiocarcinoma. ERCP and cholangioscopy are essential for timely and accurate diagnosis. IPMN-B with HGD is treated similar to cholangiocarcinoma. Following surgery, recurrence rate varies from 20% to 60%, depending on the presence of invasive components. Postoperative surveillance with MRCP is typically recommended. The precise pathogenesis of IPMN-B is unclear, necessitating further research to better understand its natural history and optimize management strategies and outcomes.



Disclosures:


Munish Ashat, MBBS¹, Joseph Brant, MD², Surbhi Dadwal, MBBS¹. P0165 - Biliary Intraductal Papillary Mucinous Neoplasm (IPMN-B) Associated With Actinomyces, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.