23 year old female who presented to the ED with abdominal pain was found to have a 9.0 cm mass in the body and tail of pancreas without evidence of ductal obstruction or involvement. Attached are the photomicrographs
PAP stained images show numerous vascular channels with tumor cells “budding” off the capillaries. The individual cells display eccentrically placed nuclei and slender cytoplasmic projections.
H&E stained image shows pseudopapillae comprised of capillary cores bordered by tumor cells
B- Catenin CD10 PR
IHCs: Beta catenin (nuclear positive) , CD10 (Membranous staining) , Progesterone receptor (Nuclear positive)
Definition
- Low grade, malignant epithelial tumors with uncertain cellular differentiation
- First described by V.K Frantz in 1959
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
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)
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)
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
Molecular / cytogenetics description
- Point mutation in exon 3 of β-cateningene (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 MYCand Cyclin D1 (Am J Clin Pathol 2017;149:67)