Editing Benign liver lesions (section)

== '''Hepatic adenoma''' ==

* Benign proliferation of hepatocytes in the context of a normal liver
* Epidemiology
** Rare
** Unifocal in 70-88% of cases
*** >10 adenomas is described as liver adenomatosis (not usually associated with OCP use)
** Mostly young women of child-bearing age (F:M 11:1)
** Main risk factor is OCP use, after as short as 6 months of use
** Sporadically associated with anabolic steroids/long-term pred
** Also seen in glycogen storage disease types I and III and FAP
* Pathophysiology
** Cords of benign hepatocytes containing increased glycogen and fat, with abnormal architecture (no bile ductules)
** Haemorrhage and necrosis commonly seen
** Can be divided into subtypes, including beta-catenin mutated adenoma, HNF1A mutated adenoma, inflammatory adenoma, and not otherwise specified adenoma 
*** Beta-catenin adenomas have the highest risk of malignant transformation
** Small potential for HCC transformation - 4.2%, with majority aoccurring in adenomas >5cm
** AFP helpful in determining malignancy
** Four subtypes of adenoma
* Presentation
** Asymptomatic 25-50% of the time
** Can cause upper abdominal pain - may be related to haemorrhage into the tumour or local compression
** Mostly found as incidental findings on CT
** Normal tumour markers
* Complications
** Spontaneous rupture/haemorrhage - can lead to uncontrolled intraperitoneal bleeding
*** Doesn't occur in lesions <5cm
*** Active/life-threatening bleeding: hepatic artery embolisation, if possible, then semi-elective resection. If haemodynamically unstable, probably need theatre. 
** Malignant transformation
*** True risk is probably low, especially in lesions <5cm
* Imaging
** See 'liver lesions' under radiology
** Imaging findings are quite specific
** Kupffer cell scan is a nuclear medicine study which can help to diagnose - not done much any more
* Management
** Asymptomatic adenoma <5cm: cease OCP or anabolic steroids. Mostly leads to shrinking, but not complete regression. Can still increase in size or rupture after cessation of OCP.
** Growth of adenoma off OCP, adenoma >5cm, adenoma in a man, or symptomatic: surgical resection.
*** Mostly need formal oncologic resection, but this is guided by individual factors. 
*** For asymptomatic adenoma >5cm in a woman on OCP, stopping OCP and reviewing in 12 months is also an option
** RFA may be possible for small/multiple adenomas not amenable to surgery.
** Pre-pregnancy resection can be considered, as behaviour during pregnancy is unpredictable
** Liver transplant has been performed for aggressive adenomatosis