American Board of Pathology (ABPath) Practice Test 2025 - Free Pathology Exam Practice Questions and Study Guide

Focal nodular hyperplasia (FNH) is characterized by a distinctive 'star-shaped' echogenicity on imaging studies, particularly ultrasound. This appearance arises from the central scar that is often present in FNH, surrounded by nodular hyperplastic liver tissue. The central scar, along with the radiating fibrous septa, gives rise to the typical appearance that can be likened to a star-like pattern.

In comparison to the other conditions listed, fatty liver disease typically presents as a diffuse increase in echogenicity due to fat accumulation but does not have the focal, star-like pattern that is characteristic of FNH. Cirrhosis may show a nodular surface with heterogeneous echogenicity, but again lacks the distinctive star-shaped appearance. Acute hepatitis usually produces a more homogenous pattern on imaging without the structural features associated with FNH. By understanding the specific imaging characteristics of focal nodular hyperplasia, one can attribute the 'star-shaped' echogenicity correctly to this condition.