Pancreatoblastoma

Definition

Carcinoma of the pancreas exhibiting multiple lines of differentiation including acinar and squamous

2/3 of cases under age 5
Usually well circumscribed
- May infiltrate
- Cellular lobules separated by fibrous bands
- Some congenital cases may be cystic
Predominant acinar component
- Sheets of cells merge with acinar formations
- Sharp cell borders
- Nuclei central to basal
- Prominent nucleoli
- Cytoplasm may be amphophilic to granular eosinophilic
  - PASd positivity variable
- Positive for trypsin, chymotrypsin and lipase (variable)
Squamoid nests required for diagnosis
- Abundant eosinophilic cytoplasm
- May be vague or with overt keratinization
- Frequently with biotin rich optically clear nuclei
Endocrine component in 2/3 of cases
- May be detectable only with stains
Ductal / glandular component occasionally present
- Usually focal
- May be mucin positive
Variably cellular stroma
- More cellular in pediatric cases
- Rarely forms bone or cartilage
- Rarely appears neoplastic
Primitive round cell component rarely present
- Uniform immature appearing small cells

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342