The goal of this national mutlticenter observational study is to learn and describe trends over time in the use of techniques for inducing hepatic hypertrophy in Italy. Patients will be treated according to the current clinical practice of the participating centers and will be observed from the moment of recruitment and throughout their stay. Information on vital status will be collected, as far as possible, for up to 5 years after surgery in order to record any events that occur in a timely manner. There are also plans to retrospectively collect data on patients who underwent hypertrophic techniques in the previous 10 years, in order to establish a historical cohort for each center that can be used for comparison with the prospective cohort.

Inclusion Criteria:

• Patients aged 18 or older
• Obtaining informed consent
• Patients with liver neoplasia (benign or malignant) and with a future liver remnant volume deemed insufficient (<20%-40%) by the local multidisciplinary team

Exclusion Criteria:

• pregnant or breastfeeding woman

The study population includes patients with potentially resectable primary or secondary liver tumors. An anatomical-pathological situation is defined as potentially resectable if a small residual liver requires regenerative procedures prior to liver resection to avoid the risk of post-resection liver failure