Mesenchymal Hamartoma


Gross Appearance
The cut surface shows numerous variably sized cystic spaces image admixed with solid areas. Minimal uninvolved liver tissue is present at the resection margin image .



image
Loose Myxoid Stroma
Low-power view shows numerous bile ducts image in a loose, myxoid mesenchymal stroma. Note the presence of a large island of normal-appearing hepatocytes image in the tumor.

image
Branching Bile Ducts
Compressed and branching bile ducts within collagenous stroma have a ductal plate malformation-like pattern image .

image
Stellate Stromal Cells
High-power view shows scattered stellate mesenchymal cells loosely embedded in an edematous stroma. Note the presence of blood vessels image .



TERMINOLOGY


Definitions




• Benign tumor primarily occurring in young children


ETIOLOGY/PATHOGENESIS


Unknown




• Presumed developmental malformation of primitive hepatic mesenchyme
image Occurs late in embryogenesis

image Postnatal growth largely due to cystic degeneration

• Evidence for neoplastic nature
image Balanced translocation involving same breakpoint at chromosome band 19q13.4 or 19q13.3

• Association with androgenetic-biparental mosaicism (ABM)
image ABM implies diploid chromosomal complement derived entirely from father in subset of cells

image ABM also predisposes to placental mesenchymal dysplasia, which has been associated with MH

• Both abnormalities are thought to lead to activation of chromosome 19 microRNA cluster in hepatic stroma


CLINICAL ISSUES


Epidemiology




• Incidence
image ∼ 5% of pediatric liver tumors

• Age
image Usually in 1st 2 years of life, < 5% after age of 5

image Rarely seen in adults

• Sex
image Male predominance in pediatric cases

image Female predominance in adult cases

Only gold members can continue reading. Log In or Register to continue

Related posts:

  1. Neonatal Hemochromatosis
  2. Autoimmune Pancreatitis
  3. Drug-Related Acute Hepatitis
  4. Biliary Atresia

Stay updated, free articles. Join our Telegram channel
Tags:
Apr 20, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Mesenchymal Hamartoma

Full access? Get Clinical Tree
Get Clinical Tree app for offline access