What is a hallmark characteristic of focal nodular hyperplasia?

Focal nodular hyperplasia (FNH) is characterized by the presence of a central stellate scar, which is a distinguishing feature of this benign liver lesion. This scar can often be seen on imaging studies, such as ultrasound or MRI, and is typically composed of fibrous tissue with a radiating pattern that can help in the diagnosis.

The presence of this central scar is directly related to the abnormal blood supply and architecture of the lesion, which sets it apart from other liver lesions. It is important to recognize this characteristic, as it plays a critical role in differentiating FNH from other hepatic lesions, such as hemangiomas or liver cancer, where such a scar is not present.

Other features, such as a fibrous capsule or the presence of cysts, might be noted in various liver lesions, but they are not specific to focal nodular hyperplasia and do not serve as hallmarks in the way the central stellate scar does. Hematoma formation is unrelated and typically does not characterize focal nodular hyperplasia at all. Understanding the unique presence of the central stellate scar is essential for accurate diagnosis and management of liver lesions.