Pathology of Liver Tumors Flashcards
What is a Von Meyenburg Complex and what causes it?
Bile duct hamartoma - caused by persistence of embryonic bile duct structores
What does a Von Meyenburg Complex look like and why is it important to identify it?
Looks like irregular, dilated bile ducts within fibrous connective tissue, and there are frequently multiple
Must be differentiated from adenocarcinoma with desmoplasia. Note: these will have non cellular atypia
What is the pathogenesis of nodular hyperplasias?
Alterations in blood supply to the liver (decreased portal vein blood flow, increasing hepatic artery blood flow)
-> too much well oxygenated blood induces growth factors which produce a nodular hyperplasia of hepatocytes which can be seen discretely on imaging
What does a focal nodular hyperplasia look like grossly?
Solitary, well-circumscribed, pale, firm lesion (<5 cm), with central stellate scar surrounded by parenchymal nodules between fibrous septae radiating outwards.
Looks alot like oncocytoma of kidney
Who tends to get focal nodular hyperplasia and how is it found?
Occurs in young adults, especially with oral contraceptives in women, or anabolic steroids in men
Usually found as an incidental finding
What are the microscopic features of focal nodular hyperplasia, and what are the clinical consequences?
Central scar, with abnormally large arterial branches accompanied by bile ductular proliferation (which don’t drain anything) and chronic inflammation, with no well defined portal triads
Hyperplasia grows between radial spokes of fibrosis
There are no clinical sequellae -> just need to differentiate between important masses
What are the gross and microscopic features of nodular regenerative hyperplasia? What is it difficult to differentiate from?
Gross - diffuse, pale, fine nodularity of the liver
Microscopic - Regenerative nodules WITHOUT fibrosis (check trichrome stain), often with obliterated portal vein branches
Lack of fibrosis will help differentiate from cirrhosis
Who is at risk for nodular regenerative hyperplasia and what is the clinical consequence?
Those with a predisposing underlying condition leading to reduced blood flow to liver: especially hematologic / neoplastic disorders (decrease blood flow due to thrombosis)
Clinical consequence: Portal hypertension can develop, like cirrhosis
What is the most common benign hepatic tumor? How does it appear grossly?
Cavernous hemangioma - can be detected on imaging
Appears grossly as a subcapsular, small, well-demarcated, soft, red-blue lesion
How does cavernous hemangioma appear microscopically?
Large, thin-walled, blood-filled spaces lined by normal-appearing endothelial cells, separated by scarce fibrous connective tissue
How should cavernous hemangioma be treated?
Do not biopsy - will bleed
Just need to differentiate from more ominous lesions
What benign liver neoplasm is most associated with oral contraceptive or estrogen use, and almost never arises outside of this context? How does it present clinically?
Hepatocellular adenoma
Present in young women on oral contraceptives. May cause an acute abdomen due to rupture and intraperitoneal hemorrhage
What do you need to differentiate hepatocellular adenoma from? Is it totally benign?
Need to differentiate from hepatocellular carcinoma
Not totally benign - may transform into hepatocellular carcinoma if Beta-catenin mutations are present
How does hepatocellular adenoma appear grossly? What is a common complication?
Solitary, well-circumscribed mass, which is tan-green (benign hepatocytes make bile), and is often subcapsular
Strangely, it is more likely to bleed that the cavernous hemangioma (another benign tumor located at the same spot made of blood vessels)
How does hepatocellular adenoma appear microscopically?
Sheets and cords of relatively normal-looking hepatocytes, containing glycogen or triglycerides (functioning properly) but with NO portal tracts and scattered arteries and veins which are prone to hemorrhage.
