What is the maximum size for focal nodular hyperplasia to be considered typical?

Focal nodular hyperplasia (FNH) is a benign liver lesion characterized by the presence of a well-circumscribed mass often containing a central scar and surrounded by normal liver tissue. While FNH can be quite variable in size, the majority of lesions that are typically classified as FNH are found to be less than 5 cm in diameter.

When lesions are larger than this size, there may be considerations for other types of liver lesions, such as hepatocellular adenomas or even malignant lesions, as larger masses can present with atypical characteristics or complications. Thus, distinguishing between FNH and other potential liver lesions becomes particularly crucial when the size exceeds the 5 cm threshold.

The distinction at the 5 cm mark helps to guide diagnostic and management strategies for liver tumors, emphasizing the importance of correlating imaging findings with clinical presentation and patient history.