Solid pseudopapillary neoplasm

Pancreas

Other tumors

Authors: Omid Savari, M.D., Joseph F. Tomashefski, Jr., M.D.

Editorial Board Member: Raul S. Gonzalez, M.D.

Deputy Editor-in-Chief: Debra L. Zynger, M.D.

Topic Completed: 1 May 2018

Minor changes: 26 October 2020

Copyright: 2002-2021, PathologyOutlines.com, Inc.

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Table of Contents

Cite this page: Savari O, Tomashefski JF. Solid pseudopapillary neoplasm. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pancreassolidpseudo.html. Accessed January 18th, 2021.

Definition / general

Low grade, malignant epithelial tumors with uncertain cellular differentiation
First described by V.K Frantz in 1959 (V.K. Frantz. Tumors of the pancreas. Bumberg C.W. (Ed.), Atlas of Tumor Pathology, Section VII)

Essential features

Presents in young women, classically as large body / tail mass
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

Located throughout the pancreas but more frequently in the body and tail
Rarely reported outside the pancreas (Virchows Arch A Pathol Anat Histopathol 1991;418:179)

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

Cyst fluid is often bloody with low CEA and low amylase (Ann Gastroenterol 2013;26:122)

Radiology description

Well circumscribed, encapsulated, heterogeneous pancreatic lesion with cystic degeneration on CT or MRI

Radiology images

Contributed by Omid Savari, M.D.

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

14 year old Hispanic girl with silent presentation of a solid pseudopapillary neoplasm of the pancreas (Am J Case Rep 2017;18:656)
16 year old boy with tonic convulsions (J Clin Res Pediatr Endocrinol. 2017;9:375)
40 year old man with subsequent multiple metastases (World J Gastrointest Oncol. 2017;9:497)
45 year old woman with situs invertus (Medicine (Baltimore) 2018;97:e0205)
62 year old woman with IgG4 related pancreatitis (Int J Surg Pathol 2017;25:271)

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

Contributed by
Omid Savari, M.D.

Predominately solid tumor

Contributed by
Dr. Andreas Schulz

Partially necrotic tumor

Contributed by
Manfred Stolte, M.D.

Invasion of spleen

Contributed by
Dr. Helmut Luchtrath

Cystic lesion

Case #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

Contributed by Omid Savari, M.D.

Solid pseudopapillary neoplasm

Solid pattern

Clear cell changes

Cholesterol cleft, scattered giant cells

Tumor invading parenchyma

Beta catenin

CD10

Ki67

Contributed by Raul S. Gonzalez, M.D.

Metastasis to liver

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

Contributed by Omid Savari, M.D.

Diff Quick

Pap

Cell block

Positive stains

β-catenin (98%)
alpha 1-antichymotrypsin (95%), alpha 1-antitrypsin (82%)
Vimentin (88%)
Cyclin D1
CD10 (63%)
SOX11 (100%)
Androgen receptor (81%), TFE3 (75%), LEF1 (93%), FUS (85%), progesterone receptor (63%), claudin7, claudin5
CD56 (96%), neuron-specific enolase (70%), synaptophysin (55%)
Cytokeratin (52%)

Negative stains

Chromogranin A (positive in only 9%)
CEA
Estrogen receptor
Loss of membranous E-cadherin

Electron microscopy description

Mitochondria-rich cytoplasm with electron-dense granules and rough endoplasmic reticulum

Electron microscopy images

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 style question #1

What is the most common gene mutation in pancreatic solid pseudopapillary neoplasm?

A. CTNNB1
B. Kit
C. PDGFRA
D. RAS

Board review style answer #1

A. Somatic point mutation of β-catenin gene (CTNNB1) is present in more than 90% of pancreatic solid pseudopapillary neoplasms

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Board review style 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 style 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.

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