Long-term follow-up of hepatic adenoma and adenomatosis: analysis of size change on imaging with histopathological correlation.

AIM: To analyse the change in size on follow-up of hepatic adenomas (HAs) and adenomatosis, and to investigate the relationship of imaging features with size change. MATERIALS AND METHODS: The study included 44 patients (142 lesions) who underwent magnetic resonance imaging (MRI) or computed tomography (CT) for diagnosis and follow-up of HA. The imaging features and percentage change in maximum tumour dimension were observed over a follow-up duration of up to 139 months. RESULTS: With an average follow-up of 43 months, 37% lesions decreased in size, 58% were stable, 4% increased; one lesion regressed completely. Adenomas were stratified into size groups (<3, 3-5, and ≥5 cm). Size change among the three groups was similar (p>0.05). Percent size change was different for lesions followed for ≤12 months (-7.2%) compared with lesions followed for 13-60 months (-20.5%), and those followed for ≥60 months (-23.5%; p<0.05); there was no difference between lesions followed for 13-60 months and ≥60 months (p=0.523). Baseline size and percent size change was similar between the hepatocyte nuclear factor 1α-inactivated HA (HA-H) and inflammatory HA (HA-I) subtype (p>0.05). CONCLUSION: Most adenomas were either stable or regressed on follow-up. Size change was independent of baseline size. After an initial size decrease within 5 years, no further size reduction was noted on extended follow-up. The percent size change in the HA-H and HA-I subtype was similar.

Functional hepatic imaging as a biomarker of primary and secondary tumor response to loco-regional therapies.

Objective criteria to measure tumor response are a key tenet for assessment of treatment efficacy when evaluating a therapeutic modality. Several response criteria have been proposed including the Response Evaluation Criteria in Solid Tumors (RECIST), modified RECIST (mRECIST), RECIST 1-1, and European Association for the Study of the Liver (EASL) guidelines. Response following loco-regional therapies (LRT) can be particularly difficult to assess as post-treatment changes may not always relate to changes in lesion size. As imaging modalities and solid tumor therapies continue to advance, there has been growing recognition that measurement of actual tumoricidal activity may not always be related to tumor size, and accurate assessment of treatment response may vary by therapeutic modality. As such, the objective change in the physical size characteristics of a tumor may not accurately reflect biological response to treatment. Functional imaging encompasses methods that are capable of detecting or measuring changes in tissue metabolism, blood flow, or composition. Conventional imaging modalities such as magnetic resonance imaging (MRI) and computed topography (CT) now include techniques such as diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) maps, dynamic contrast enhancement (DCE-MRI), and perfusion CT (pCT). Use of functional cross-sectional imaging is particularly relevant to assess primary and secondary hepatic malignancies treated with LRT, such as trans-arterial chemoembolization (TACE), radiofrequency ablation (RFA), yttrium-90 (Y-90), and hepatic arterial infusion (HAI) chemotherapy. We herein review the imaging techniques, as well as the methodologies for measuring tumor response and survival, among patients treated with LRT for primary and secondary hepatic malignancies.