Hepatic fat fraction and lipid content of adrenal adenomas: insights from unenhanced CT

Adrenal incidentalomas (AI) are increasingly detected with the widespread use of abdominal computed tomography (CT). Although a relationship between AI, metabolic syndrome, and metabolic dysfunction-associated steatotic liver disease (MASLD) has been suggested, the evidence remains limited.

To investigate the relationship between hepatic fat fraction (HFF) and lipid content of adrenal adenomas using unenhanced CT.

This retrospective study included 176 patients (211 adrenal adenomas) diagnosed on unenhanced CT between September 2023 and June 2025. Adrenal adenomas were defined as lesions with attenuation ≤ 10 Hounsfield units (HU) or > 10 HU with stability on follow-up imaging. Hepatic attenuation was measured in three regions, and HFF was calculated with the formula: Fat fraction = - 0.58 × CT(HU) + 38.2. Patients were classified into four steatosis groups (normal, mild, moderate, severe). The fibrosis-4 index (FIB-4) was calculated to assess liver fibrosis. Statistical analyses included the Kruskal-Wallis H test for continuous variables, Chi-square test for categorical comparisons, and Pearson's correlation for associations.

The study population consisted of 59% females and 41% males, with a mean age of 59 years. Most adenomas were nonfunctioning (94%). Adenoma attenuation ranged from - 89 to + 28 HU. No significant correlation was found between adrenal adenoma attenuation and liver attenuation or HFF (p = .519 and p = .566, respectively). A weak negative correlation was observed between adenoma diameter and HFF (r = -.137, 95% CI: - 0.25 - - 0.02; p = .046). No association was found between hepatic steatosis and FIB-4 index.

This study did not demonstrate a significant relationship between adrenal adenomas and MASLD. Hepatic steatosis and lipid content of adrenal adenomas appear to represent independent processes.