Fig. 1.

Patient selection and cohort population. Sixty-one female patients were identified with hepatocellular adenoma. Exclusions were procedural intervention prior to follow-up scan (n = 17), absence of two or more scans (n = 7), or unknown type or duration of hormonal exposure (n = 10). Of the 27 patients meeting study criteria, distinct periods of hormone exposure were analyzed (some individuals had multiple discrete periods of hormone exposure were counted in each respective group). The total number of periods of with discrete nonoverlapping periods of hormone exposure was 34 (19 intervals without hormone exposure, seven periods of estrogen exposure, and eight periods of progestin-only exposure).