Von meyenburg complexes mimicking liver metastases
Authors: Laura Lorenzon, Vincenzo Ziparo
Journal: Hepatology (2011)

A 68-year-old man was admitted to our department with synchronous rectal and right colon cancers. A preoperative chest-abdomen computed tomography scan was negative for metastases or liver disease (Fig. 1A), and liver function tests were within normal values; thus, total colectomy was planned. A surgical exploration of the liver surface showed multiple gray-white, nodular lesions less than 5 mm in diameter that were scattered on the surfaces of both liver lobes and were suggestive of multiple metastases (Fig. 1B). An examination of the peritoneal cavity revealed synchronous colon carcinomas with no signs of carcinomatosis. A frozen liver biopsy section was tested because miliary metastases were suspected, but the findings were consistent with von Meyenburg complexes; the patient underwent total colectomy. The definitive histological examination confirmed a diagnosis consistent with von Meyenburg complexes (Fig. 1C) and synchronous pT3 N0 colon cancers. (A) Preoperative computed tomography scan. (B) Surgical exploration: multiple gray-white, miliary lesions scattered on the surfaces of both liver lobes (the arrow points to the biopsy site). (C) Von Meyenburg complexes: a histological section showing dilated lumens of irregular bile ducts containing bile with no signs of malignancies (the photograph was provided by courtesy of Dr. Emanuela Pilozzi, Department of Pathology, Faculty of Medicine and Psychology, Sapienza University of Rome, St. Andrea Hospital, Rome, Italy). First described by von Meyenburg in 1918,1 von Meyenburg complexes are usually described as bile duct microhamartomas, and they comprise a variable number of dilated bile ducts embedded in a fibrous stroma containing inspissated bile concrements.2 They often present as multiple lesions and occur in a normal liver or are associated with Caroli disease, congenital hepatic fibrosis, or autosomal dominant polycystic kidney disease.2, 3 Von Meyenburg complexes have been thought to result from a ductal plate malformation of the peripheral interlobular bile ducts.2 Past autopsy series have reported the detection of von Meyenburg complexes in 0.9% to 5.6% of cases.3 Von Meyenburg complexes are clinically significant because they can be erroneously confused with liver metastases.4, 5 A possible preoperative imaging diagnosis of von Meyenburg complexes seems to depend on the size of the bile duct structure in each hamartoma. A computed tomography scan of the liver may show von Meyenburg complexes as small, hypodense nodules with ringlike enhancement.4 Magnetic resonance cholangiography seems to be the best imaging tool because it can differentiate saccular dilatation of the biliary system (Caroli disease) from periductal cystic dilatation (multiple-abscess polycystic disease).4 Even though the clinical features of this patient (no signs of peritoneal carcinomatosis and normal liver function tests) would have been unusual for metastases affecting both lobes of the liver, the macroscopic appearance was highly suspicious for metastasization, and biopsying a small lesion was mandatory for the management of this case. The diagnosis of von Meyenburg complexes requires a histological examination showing cystic dilatation of bile ducts embedded in a fibrous stroma with no signs of malignancies.