Solid-Pseudopapillary Tumors

Solid-Pseudopapillary Tumors
Grace E. Kim, MD
Key Facts
Terminology
  • Solid-pseudopapillary tumor (SPT)
  • Low-grade malignant neoplasm of uncertain cellular differentiation
Etiology/Pathogenesis
  • 90-100% harbor mutations in β-catenin gene
Clinical Issues
  • Occurs predominately in young females
  • Presents with nonspecific symptoms related to intraabdominal mass
  • Can be located in head, body, or tail of pancreas
  • Indolent and nonaggressive behavior
  • Metastasis in 10-15% of cases to liver, peritoneum, and lymph node
  • > 80% are cured with surgical resection
Microscopic Pathology
  • Well-demarcated large mass
  • Solid monomorphic sheets of polygonal cells
  • Delicate vessels surrounded by hyalinized or myxoid stroma
  • Characteristic degenerative change
    • Pseudopapillae formation
  • Intracytoplasmic eosinophilic hyaline globules (PASD positive)
  • Uniform round to oval nuclei with finely dispersed chromatin
  • Neoplastic cells often have nuclear grooves
  • Immunoreactivity for β-catenin (nuclear staining)
Top Differential Diagnoses
  • Pancreatic endocrine tumor
This well-demarcated tumor has a soft and friable solid surface with hemorrhagic areas. Grossly, this could mimic a pancreatic endocrine tumor.
An SPT can also present as a well-demarcated hemorrhagic cystic mass that could, on imaging or gross examination, mimic a pseudocyst.
TERMINOLOGY
Abbreviations
  • Solid-pseudopapillary tumor (SPT)
  • Solid-pseudopapillary neoplasm (SPN)
Synonyms
  • Plethora of descriptive names
    • Solid and papillary epithelial neoplasm
    • Solid cystic tumor
    • Papillary and cystic neoplasm
    • Frantz tumor
Definitions
  • Low-grade malignant neoplasm of uncertain cellular differentiation
  • Originally described in 1959
ETIOLOGY/PATHOGENESIS
Cellular Lineage
  • Uncertain
    • Electron microscopy shows evidence of epithelial differentiation
Molecular
  • 90-100% harbor mutations in β-catenin gene
CLINICAL ISSUES
Epidemiology
  • Incidence
    • Uncommon
    • 1-2% of all exocrine pancreatic tumors
  • Age
    • Most patients in 20s and 30s
      • Mean: 25-35 years
      • Overall age range: 7-79 years
  • Gender
    • Female predominance
      • Male to female ratio 1:9-20
Site
  • Evenly distributed throughout pancreas
Presentation
  • Nonspecific symptoms related to intraabdominal mass
    • Vague abdominal pain
    • Weight loss
    • Anorexia
  • May have palpable abdominal mass
  • Up to 1/3 of cases discovered incidentally
  • Complications
    • Rupture
    • Hemoperitoneum
Laboratory Tests
  • Serum oncomarkers, laboratory tests usually normal
Natural History
  • Most are indolent, slow-growing, and nonaggressive
  • May directly invade stomach, duodenum, spleen
  • Metastasis
    • 10-15% of cases
    • Liver, peritoneum, lymph nodes
      • Peritoneal metastases more common in patients with trauma, rupture, or drainage of neoplasm
  • Rare, clinically aggressive variant
Treatment
  • Surgical resection is treatment of choice
  • Can recur if incompletely resected
Prognosis
  • Excellent
    • > 80% cured with surgical resection
    • 10-15% of cases have metastases or recurrence
    • Even patients with metastases have favorable longterm survival
  • No proven morphologic predictors of outcome
IMAGE FINDINGS
General Features
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Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Solid-Pseudopapillary Tumors

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