Malignant neoplasms of gallbladder

**Definition:** A malignant tumour arising from the epithelium of the gallbladder. It is usually associated with the presence of gallstones. Clinical symptoms are not specific and usually present late in the course. Morphologically, adenocarcinoma is the most common type, however squamous cell carcinomas, adenosquamous carcinomas, signet ring carcinomas, and undifferentiated carcinomas can also occur.