HNF1A-Inactivated Hepatocellular Adenoma in a Young Woman

Case at a Glance

A 32-year-old female presents with a 4.6 cm hepatic adenoma suspected to be HNF1A subtype, discovered incidentally during evaluation for chronic gastritis. Patient has a history of oral contraceptive use and previous thyroidectomy.

Patient's Story

The patient initially presented with symptoms of chronic gastritis. During routine abdominal ultrasound evaluation for her gastric symptoms, a hepatic mass was incidentally discovered. She has a significant medical history including thyroidectomy in 2017 and previous use of oral contraceptives, which she discontinued in 2022. The patient reports anxiety about her diagnosis and upcoming follow-up imaging studies.

Initial Assessment

Physical examination was unremarkable. Laboratory studies including complete blood count (CBC) and basic metabolic panel (BMP) showed normal liver function tests. Initial ultrasound revealed a hepatic mass without evidence of hepatic steatosis or cirrhosis. The patient was advised to discontinue all hormonal medications and contraceptives.

The Diagnostic Journey

MRI with and without contrast was performed, revealing a 4.6 x 4.0 x 4.3 cm mass in hepatic segment 8. The lesion demonstrated mild T2 hyperintensity, early arterial enhancement with mild persistence on delayed phases, decreased T1 signal intensity, and significant signal loss on out-of-phase imaging suggesting intrinsic fat content. The mass showed a multilobular appearance with associated restricted diffusion throughout. These imaging characteristics were highly suggestive of hepatocellular adenoma, specifically favoring the HNF1A subtype.

Final Diagnosis

HNF1A-inactivated hepatocellular adenoma measuring 4.6 cm in hepatic segment 8. The diagnosis was supported by characteristic imaging findings including signal loss on out-of-phase sequences indicating intracellular fat, which is pathognomonic for this adenoma subtype.

Treatment Plan

Conservative management with hormonal avoidance was initiated. The patient was counseled to permanently discontinue oral contraceptives and avoid hormone replacement therapy. Follow-up MRI surveillance was scheduled at 6-month intervals to monitor for size changes. Given the lesion size (>5 cm threshold), biopsy consideration was discussed but deferred in favor of imaging surveillance given the classic radiologic appearance.

Outcome and Follow-up

The patient was reassured about the benign nature of HNF1A-type adenomas and their essentially zero malignant transformation risk. She was scheduled for repeat MRI imaging to assess for any interval changes. Patient education focused on the importance of avoiding hormonal medications and regular surveillance imaging. The patient expressed improved understanding and reduced anxiety regarding her diagnosis after receiving detailed explanation of the benign nature of her specific adenoma subtype.