The original version of this article, published on 09 April 2018, unfortunately contained a mistake. The following correction has therefore been made in the original: The presentation of Fig. 2 was incorrect, "Cotton ball sign" was mistakenly named "Polka-dot sign".

The exact pathogenesis of gallbladder adenomyomatosis is still lacking and some controversies over its diagnosis and treatment exist. Originally recognized as a precancerous lesion, adenomyomatosis is currently recognized by recent studies as a benign alteration of the gallbladder that is often associated with cholecystitis and cholecystolithiasis. Gallbladder carcinoma is an extremely malignant disease with a 5-year survival rate of less than 5%. Therefore, it is important to diagnose, differentiate, and confirm the relationship between adenomyomatosis and early-stage gallbladder carcinoma. However, the early clinical symptoms of adenomyomatosis are extremely similar to those of gallbladder stones and cholecystitis, increasing the difficulty to identify and treat this disease. This article summarizes the research progress on gallbladder adenomyomatosis, aiming to improve the understanding of the pathogenesis of adenomyomatosis and further provide insight for its clinical diagnosis and treatment.

Few things in radiology are "pathognomonic" in their appearance or presentation. However, having an awareness of those findings which are specific to a certain entity is important when interpreting imaging studies. These classic findings can be identified with many imaging modalities, but no modality provides as many recognizable observations as an MRI. This results from the large variety of pulse sequences that provide high contrast resolution, prior to and following contrast administration. In this article, the most classically recognized abdominal findings are presented including the following: Liver: Cyst, hemangioma, focal nodular hyperplasia, hepatic adenoma, hemosiderosis, hepatocellular carcinoma. Spleen: Cyst, hemangioma, lymphangioma, hemosiderosis, Gandy-Gamna bodies. Biliary system: Biliary stones and choledocholithiasis, pneumobilia, choledochal cyst. Gallbladder: Adenomyomatosis, sludge, surgical clips in the gallbladder fossa. Pancreas: Pancreatic divisum, intraductal papillary mucinous neoplasm, pseudocyst, autoimmune pancreatitis, chronic pancreatitis, adenocarcinoma. Kidneys: Simple cyst, hemorrhagic cyst, renal sinus cyst, angiomyolipoma, solid mass.

Gallbladder adenomyomatosis (GAM) is an acquired, reactive, tumor-like condition. Malignant transformation is extremely rare, and imaging features during contrast-enhanced ultrasound (CEUS) have not been described before. Herein, we describe a 73-year-old Asian man who had been diagnosed with gallbladder carcinoma by conventional ultrasonography (US). Based on additional radiological findings, we believed that it was a localized adenomyomatosis. However, the histopathological diagnosis was adenocarcinoma originate from adenomyomatosis with serosal invasion. We believe this is the first case of adenocarcinoma derived from GAM with characteristics of CEUS findings. This case is presented to indicate a clinical awareness of malignant transformation of GAM and discuss the radiology significance with an emphasis on CEUS.

Adenomyomatosis, which is also known as adenomyoma or adenomyomatous hyperplasia of the gallbladder, is one of the two hyperplastic cholecystoses. The other hyperplastic cholecystosis is cholestesterolosis, also known as "strawberry gallbladder." Adenomyomatosis is a benign condition that is pathologically characterized by hyperplasia of the gallbladder wall mucosa and muscularis propria, with pathognomonic epithelial invaginations forming cystic pockets (Rokitansky-Aschoff sinuses). These sinuses may contain calculi and/or cholesterol crystals. The gallbladder wall thickening, Rokitansky-Aschoff sinuses, and the calculi and/or cholesterol crystals that are often found in sinuses characterize the imaging appearance of adenomyomatosis. Sometimes, particularly when the characteristic imaging findings are not present, adenomyomatosis can be difficult to distinguish from gallbladder cancer based on the diagnostic imaging findings. Adenomyomatosis is often asymptomatic and incidentally detected, requiring no specific treatment. Adenomyomatosis also can be associated with right upper quadrant pain. In cases where it is difficult to distinguish adenomyomatosis from gallbladder cancer or when adenomyomatosis is associated with right upper quadrant pain, this condition may be treated with a cholecystectomy.