Isolated Tubulovillous Adenoma of the Bile Duct

Abstract

Adenomas of the bile duct typically occur as extensions of ampullary neoplasms. We describe a rare case of an isolated tubulovillous adenoma of the bile duct presenting with painless jaundice and a bile duct stricture on imaging. A 69 year-old Caucasian male with myelodysplastic syndrome (MDS) presented with 3 months of “teacolored” urine and worsening pruritis. Physical examination was most pertinent for scleral icterus, and absence of abdominal tenderness. Laboratory studies were were as follows: alkaline phosphatase 384 IU/L, aspartate transaminase (AST) 60 IU/L, alanine aminotransferase (ALT) 80 IU/L, total bilirubin 12.6 mg/dL, and conjugated bilirubin 10.2 mg/dL. CA 19-9, carcinoembryonic antigen (CEA), and alpha-fetoprotein (AFP) levels were 53 U/ml, 1.2 ng/ml, and 1.5 ng/mL respectively. Magnetic resonance cholangiopancreatography (MRCP) detected a 10-mm length stricture superior to the intra-pancreatic portion of the bile duct, with proximal dilatation of the bile ducts up to a diameter of 18 mm (Figure 1). The patient underwent endoscopic retrograde cholangiography (ERC) with cholangioscopy. Frond-like tissue was visualized immediately distal to the cystic duct (figure 2). The lesion was biopsied under direct cholangioscopic visualization using a mini-forceps. Biopsies demonstrated glandular columnar epithelium in a mixed tubular and villous pattern, with enlarged hyperchromatic nuclei and loss of nuclear polarity, consistent with tubulovillous adenoma (figure 3). No invasive cancer was present in the specimen. A plastic stent was placed, and the patient was referred to surgical oncology. Surgery has been deferred due to underlying MDS. At approximately 6 months after initial presentation, he has no recurrent jaundice, abdominal pain or unintentional weight loss.1299_A.tif Figure 1: MRCP demonstrates a stricture in the common bile duct with upstream dilatationUnlike colon, rectal and ampullary adenomas, isolated tubulovillous adenomas of the bile duct are exceedingly rare. Histologically, they are similar to tubulovillous adenomas in other parts of the gastrointestinal (GI) tract and have the potential to progress to invasive cancer. In fact, foci of adenocarcinoma have been reported in the surgical specimen of patients whose bile duct biopsies demonstrated only adenomatous tissue. Therefore, surgical resection is recommended for patients who are reasonable operative candidates. For patients who are not operative candidates or decline surgery, endoscopic stenting can provide effective palliation for symptomatic jaundice.1299_B.tif Figure 2: Cholangioscopy of the bile duct identified frond-like tissue immediately distal to the cystic duct1299_C.tif Figure 3: Targeted biopsy consistent with tubulovillous adenoma (glandular columnar epithelium in a mixed tubular and villous pattern, with enlarged hyperchromatic nuclei and loss of nuclear polarity)