Pancreas
Exocrine tumors / carcinomas
Solid pseudopapillary neoplasm

Author: Omid Savari, M.D.
Editor: Joseph F. Tomashefski, M.D.
Deputy Editor Review: Debra Zynger, M.D.

Revised: 9 July 2018, last major update May 2018

Copyright: (c) 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: Solid pseudopapillary tumor[TI] pancreas[TI] free full text[sb]

Cite this page: Savari, O. Solid pseudopapillary neoplasm. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/pancreassolidpseudo.html. Accessed July 15th, 2018.
Definition / general
Essential features
  • Presents in young women
  • Variable amount of solid and cystic formation at gross exam
  • Papillary fronds on myxoid or hyalinized vascular stalk lined by poorly cohesive, uniform cells with nuclear grooves comprising solid and cystic areas
  • β-catenin positive
Terminology
  • Also known as solid pseudopapillary tumor, papillary epithelial neoplasm, papillary cystic neoplasm, solid and papillary neoplasm, low grade papillary neoplasm and Hamoudi or Frantz tumor
Epidemiology
  • Represents 1-2% of pancreatic neoplasms
  • Mainly young females are affected - the female to male ratio is 10:1
  • Usually presents in the third to fourth decade of life (mean age 35 years)
  • In men tends to occur at an older age with more aggressive behavior (Surgery 2008;143:29)
Sites
Clinical features
  • The most common symptoms are abdominal pain and a palpable, non-tender, upper abdominal mass
  • Also symptoms related to an intra-abdominal mass effect, such as discomfort, nausea, vomiting and early satiety
Laboratory
Radiology description
  • Well circumscribed, encapsulated, heterogeneous pancreatic lesion with cystic degeneration on CT or MRI
Radiology images

Images hosted on PathOut server:

Contributed by Dr. Omid Savari:

MR of abdomen



Images hosted on other servers:

Hypodense lesion

Endoscopic ultrasound

Multiple metastases

Prognostic factors
  • Poor prognostic factors include: size > 5 cm, male gender, necrosis, cellular atypia, vascular invasion, perineural invasion and invasion into adjacent structures (Dig Liver Dis 2013;45:703)
Case reports
Treatment
  • Surgical resection is curative in more than 95% of cases
Gross description
  • Range from 0.5 to 34.5 cm with a mean diameter of 6 cm
  • Well defined, encapsulated with variable amount of solid and cystic patterns
  • Smaller lesions tend to be more solid but less sharply circumscribed
  • Larger tumors demonstrate a fibrous pseudocapsule and have a variegated and friable cut surface
  • Cystic degeneration and hemorrhage are common findings in larger specimens
Gross images

Images hosted on PathOut server:

Contributed by
Dr. Omid Savari

Predominately solid tumor


 Contributed by
 Dr. Andreas Schulz

Partially necrotic tumor


 Contributed by
 Dr. Manfred Stolte

Invasion of spleen


 Contributed by
 Dr. Helmut Luchtrath

Cystic lesion


 Case of the Week
 #121

Multilocular cystic mass

Microscopic (histologic) description
  • Solid nests of poorly cohesive cells forming a cuff surrounding blood vessels, resulting in a pseudopapillary architecture
  • Stroma usually shows various degrees of hyalinization or evidence of degeneration such as hemorrhage, foamy macrophages, calcification and cholesterol clefts
  • Tumor cells usually have a moderate amount of eosinophilic cytoplasm with large intracytoplasmic hyaline globules and perinuclear vacuoles
  • Relatively uniform nuclei with finely textured chromatin, inconspicuous nucleoli and characteristic longitudinal grooves
  • Oncocytic or clear cell changes may occur
  • Rare mitotic figures
  • Although grossly well circumscribed, microscopic finding of infiltration to the surrounding pancreatic tissue is not uncommon
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Dr. Omid Savari

Solid pseudopapillary neoplasm

Beta catenin

CD10

Ki67


Solid pattern

Clear cell changes

Cholesterol cleft, scattered giant cells

Tumor invading parenchyma

Cytology description
  • Cellular smears with delicate papillary fronds
  • Tumor cells cells are usually bland and uniform with a moderate amount of cytoplasm, which usually contains variable sized clear perinuclear vacuoles or cytoplasmic eosinophilic hyaline globules
  • Nuclei are round to oval with grooves and finely granular chromatin (J Cytol 2010;27:118, Arch Pathol Lab Med 2017;141:990)
Cytology images

Images hosted on PathOut server:

Contributed by Dr. Omid Savari

Diff Quick

Pap

Cell block


Positive stains
Negative stains
Electron microscopy description
  • Mitochondria-rich cytoplasm with electron-dense granules and rough endoplasmic reticulum
Electron microscopy images

Images hosted on PathOut server:

Contributed by Dr. H.D. John, Mainz

Abundant mitochondria

Granules

Molecular / cytogenetics description
  • Point mutation in exon 3 of β-catenin gene (CTNNB1) is present in more than 90%
  • Gene mutation results in the accumulation of β-catenin in the cytoplasm and formation of a β-catenin–Tcf/Lef complex, through which the Wnt signaling pathway activates several oncogenic genes such as MYC and Cyclin D1 (Am J Clin Pathol 2017;149:67)
Differential diagnosis
  • Pancreatic neuroendocrine tumor: small to medium sized cells with uniform nuclei and finely granular chromatin (salt and pepper appearance), arranged in organoid, trabecular or nested patterns; positive for neuroendocrine markers and negative for β-catenin
  • Acinar cell carcinoma: prominent acinar formation and cells with finely granular cytoplasm; positive for pancreatic enzymes and variable staining for β-catenin
  • Pancreatoblastoma: primitive pancreatic elements with acinar, ductal and neuroendocrine differentiation; also squamoid corpuscles; more common in children younger than 10 years; positive for β-catenin (80%), neuroendocrine markers and pancreatic enzymes (trypsin, chymotrypsin and lipase)
Board review question #1
What is the most common gene mutation in pancreatic solid pseudopapillary neoplasm?

A. CTNNB1
B. Kit
C. PDGFRA
D. RAS
Board review answer #1
A. Somatic point mutation of β-catenin gene (CTNNB1) is present in more than 90% of pancreatic solid pseudopapillary neoplasms
Board review question #2
What are the lab findings in pancreatic solid pseudopapillary neoplasm cyst fluid?

A. High amylase and high CEA
B. High amylase and low CEA
C. Low amylase and high CEA
D. Low amylase and low CEA
Board review answer #2
D. Although non-specific, cyst fluid analysis of pancreatic solid pseudopapillary neoplasm shows low amylase and low CEA. The same results also can be detected in serous cystic tumors.