Subcentimeter hepatocellular carcinoma (HCC) on gadoxetic-acid-enhanced MRI: less frequent typical imaging features compared to 1–2 cm HCC but better prognosis after surgical resection

Purpose To compare the imaging features, pathologic characteristics, and survival outcomes between subcentimeter and 1–2 cm hepatocellular carcinoma (HCC). Methods This retrospective observational study evaluated the imaging features and medical records of patients with HCC smaller than 2 cm who underwent surgical resection with preoperative gadoxetic-acid-enhanced MRI (EOB-MRI) from January 2013 to December 2021. The incidence of EOB-MRI features and pathological characteristics between the subcentimeter and 1–2 cm HCC were compared. The recurrence-free survival (RFS), including early and overall tumor recurrence, and overall survival (OS) were assessed. Results A total of 223 patients (82 with subcentimeter HCC and 141 with 1–2 cm HCC, 179 men) were enrolled. Compared with 1–2 cm HCC, subcentimeter HCC showed fewer restricted diffusion (87.8 vs. 95.7%, P = 0.027), portal-phase washout (58.5% vs. 73.8%, P = 0.013), typical enhancement pattern (50.0% vs. 66.7%, P =0.014), and microvascular invasion (4.9% vs. 14.9%, P = 0.022). Patients with subcentimeter HCC had higher RFS ( P = 0.027) and better OS ( P = 0.029). The estimated RFS rates at 5 years was 83.3% for subcentimeter HCC and 67.3% for 1–2 cm HCC, respectively. The estimated OS rates at 5 years was 97.3% for subcentimeter HCC and 89.5% for 1–2 cm HCC, respectively. Conclusion Subcentimeter HCC showed less frequent EOB-MRI features seen typically in 1–2 cm HCC but better survival outcomes. Therefore, tailored early diagnostic criteria and immediate treatment for subcentimeter HCC may be warranted. Graphical abstract