To summarize the clinical and ultrasound characteristics of hepatocellular adenoma to improve its diagnosis.

The clinical, imaging, and pathological data of 10 patients with hepatic adenoma (HCA group), 17 patients with hepatic angiomyolipoma (CMAL group), and 40 randomly selected AFP negative hepatocellular carcinoma patients (HCC (AFP-) group) diagnosed at the Third Affiliated Hospital of Sun Yat-sen University from January 2008 to May 2021 were retrospectively reviewed. The t-test and chi-square test were used to compare the clinical characteristics and ultrasound and contrast-enhanced ultrasound findings in the three groups.

The average age of onset in the HCA group was (36.40±16.68) years old. The gender (male/female: 5/5 vs 36/4) and hepatitis virus infection status (yes/no: 0/10 vs 40/0) of the patients in the HCA group (yes/no: 0/10 vs 40/0) were statistically different from those of the HCC (AFP-) group (χ²=8.672, P=0.010; χ²=50.000, P＜0.001), but showed no statistical difference from those of the CAML group (P＞0.05 for all). There were statistically significant differences in tumor echo between the HCA (unspecific tumor echo) and HCC (AFP-) (mostly hypoechoic) groups (χ²=8.404, P=0.011), though there was no significant difference in tumor number, size, morphology, or blood supply (P＞0.05 for all). There was also no significant difference in tumor number, size, boundary, echo, morphology, or blood supply of lesions between the HCA and CAML groups (P＞0.05 for all). The CEUS pattern was mainly "hyperintense-isointense-isointense" for HCA lesions, "hyperintense-hypointense-hypointense" for HCC (AFP-) lesions, and "hyperintense-hyperintense-isointense" or "hyperintense-isointense-isointense" for CAML lesions. The CEUS pattern between the HCA group and the CAML group was not statistically different. There was a statistically significant difference in the enhancement patter in the portal phase (hyperintense/isointense/hypointense: 1/6/3 vs 0/4/36; χ²=15.106, P＜0.001) and the delayed phase (hyperintense/isointense/hypointense: 0/6/4 vs 0/1/39; χ²=12.500, P=0.002) between the HCA group and the HCC (AFP-) group, but there was no statistically significant difference in the arterial phase (P＞0.05).

Hepatic adenoma has certain clinical, conventional two-dimensional ultrasound, and contrast-enhanced ultrasound features. Attention should be paid to the possibility of hepatic adenoma in women, patients without hepatitis B infection and those with a "hyperintense-isointense-isointense" pattern on CEUS.