Case 340 -- Familial adenomatous polyposis: A molecular diagnostic approach

Contributed by Diana Ionescu, MD*, Federico Monzon, MD*, Georgios Papachristou MD**, Robert Schoen MD**, Karen Weck, MD* and Sydney Finkelstein, MD, PhD*
  University of Pittsburgh Medical Center, *Department of Pathology and Laboratory Medicine and **Department of Medicine
Published on line in February 2003


This 42-year-old Caucasian woman was referred for diagnosis and therapy of an ampullary adenoma. The patient had been in good health until 3 months earlier, when she developed episodic right upper quadrant (RUQ) and back pain. On gallbladder ultrasound, there was evidence of calcified gallstones with normal gallbladder wall and bile duct. Laboratory tests revealed a mild elevation in alanine amino-transferase (ALT) (48 U/liter). The CBC, chemistry profile, aspartate aminotransferase (AST), alkaline phosphatase, total bilirubin, lipase, and the urine analysis were normal. Family history includes: mother deceased of breast cancer at age 64, father deceased at age 72 of coronary artery disease. and one sister who died at age 37 of renal cancer (she is one of four children). She has a 14 and a 21-year-old child.

A laparoscopic cholecystectomy was performed, and on pathologic examination, chronic follicular cholecystitis and two 7 mm jet black, irregular gallstones were found. The patient continued to experience occasional atypical RUQ pain. Laboratory tests followed on an outpatient basis revealed persistent minor elevation of AST and ALT. A computed tomographic (CT) examination of the abdomen showed a normal pancreas and a dilated common bile duct consistent with prior cholecystectomy.

A magnetic resonance cholangiopancreatography (MRCP) was performed and disclosed mild intrahepatic biliary duct dilation, and moderate dilation of the common duct, measuring up to 15 mm in diameter. The distal common bile duct showed normal tapering, with no evidence of obstructing mass or calculus at the level of the pancreatic head. An upper endoscopy showed small benign-appearing fundal polyps (pathology showed on figure 1), and a hypertrophied, friable ampulla of Vater. Brushings of the ampulla disclosed clusters of atypical columnar epithelial cells, and biopsy revealed tubular adenoma without high-grade dysplasia (figure 2). Colonoscopy was performed and demonstrated numerous colonic polyps measuring 3-5 mm in diameter, and one 1 cm sigmoid polyp. The sigmoid polyp was a tubulovillous adenoma (figure 3) and the smaller polyps were tubular adenomas.

A duodenal endoscopic ultrasound (EUS) showed a mass measuring 20 mm confined to the mucosa with possible extension into the distal bile duct. ERCP showed dilated pancreatic and common bile ducts with no ductal involvement by the mass.

On exploratory laparotomy, a transduodenal ampullectomy and a total abdominal colectomy with end-to-end ileorectal anastomosis was performed. The colon resections were 50 cm and 22 cm in length with an open circumference ranging between 4.5 and 9.0 cm. The colonic mucosa was tan and involved with innumerable (>100) small tan, round, sessile nodules (polyps), distributed throughout the entire colon, all less than or equal to 0.2 cm in diameter (figure 4). In addition, multiple diverticula were present (figure 5). There were no dominant or ulcerating lesions identified. It is important to mention that although the number of colonic polyps was higher then 100, they were scattered throughout the colon (with rectal sparing on endoscopic examination) instead of confluent. On microscopic examination diffuse adenomatous changes of the colonic mucosa were seen, but there was no evidence of high-grade dysplasia or carcinoma (figure 6). The ampullary tumor was a tubulovillous adenoma without high-grade dysplasia.

High clinical suspicion and adenomatous pathological findings throughout the gastrointestinal tract prompted the request for molecular and genetic testing for familial adenomatous polyposis (FAP).



Case IndexCME Case StudiesFeedbackHome