BACKGROUND: Hepatocellular adenoma (HCA) is a benign liver tumour that may be complicated by bleeding or malignant transformation. Present guidelines advise cessation of oral contraceptives and surgical resection if the lesion is still larger than 5 cm at 6 months after diagnosis. The aim of this study was to evaluate whether this 6-month interval is sufficient to expect regression of a large HCA to 5 cm or smaller.
METHODS: This retrospective cohort study included all patients with an HCA larger than 5 cm diagnosed between 1999 and 2015 with follow-up of at least 6 months. Medical records were reviewed for patient characteristics, clinical presentation, lesion characteristics, management and complications. Differences in characteristics were assessed between patients kept under surveillance and those who underwent treatment for an HCA larger than 5 cm.
RESULTS: Some 194 patients were included, of whom 192 were women. Eighty-six patients were kept under surveillance and 108 underwent HCA treatment. Patients in the surveillance group had a significantly higher BMI (P = 0·029), smaller baseline HCA diameter (P < 0·001), more centrally located lesions (P < 0·001) and were more likely to have multiple lesions (P = 0·001) than those in the treatment group. There were no significant differences in sex, age at diagnosis, symptoms, complication rates and HCA subtype distribution. Time-to-event analysis in patients managed conservatively and those still undergoing treatment more than 6 months after diagnosis showed that 69 of 118 HCAs (58·5 per cent) regressed to 5 cm or smaller after a median of 104 (95 per cent c.i. 80-128) weeks. Larger HCAs took longer to regress (P < 0·001). No complications were documented during follow-up.
CONCLUSION: This study suggests that a 6-month cut-off point for assessment of regression of HCA larger than 5 cm to no more than 5 cm is too early. As no complications were documented during follow-up, the cut-off point in women with typical, non-β-catenin-activated HCA could be prolonged to 12 months, irrespective of baseline diameter.,
British Journal of Surgery
Erasmus MC: University Medical Center Rotterdam

Klompenhouwer, A. J., Bröker, M., Thomeer, M., Gaspersz, M., de Man, R., & IJzermans, J. (2017). Retrospective study on timing of resection of hepatocellular adenoma. British Journal of Surgery, 104(12), 1695–1703. doi:10.1002/bjs.10594