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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