What type of benign liver mass is characterized by blood-filled vascular spaces?

A hemangioma is the correct answer because it is a benign liver tumor characterized by the presence of dilated blood vessels that create blood-filled vascular spaces. This type of liver mass is often asymptomatic and is usually discovered incidentally during imaging tests such as ultrasound, CT, or MRI. The vascular nature of hemangiomas is what distinguishes them from other types of benign liver lesions, making the identification of these blood-filled spaces a key feature in their diagnosis.

In contrast, focal fatty sparing refers to areas of liver tissue that are spared from fat infiltration due to various reasons, but it does not represent a mass or tumor. Cholestasis describes a condition in which bile flow is impaired, leading to bile accumulation, and is not a tumor or mass. Adenomas are benign liver tumors that are comprised of hepatocytes, but they do not have the characteristic vascular spaces seen in hemangiomas. These differences highlight why hemangioma is specifically recognized for its vascular profile among liver masses.