Stanford School of Medicine

Surgical Pathology Criteria

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Duodenum (Psammomatous) Somatostatinoma


  • Well differentiated duodenal neoplasm composed entirely of somatostatin producing cells, frequently containing psammoma bodies

Alternate/Historical Names

  • D cell tumor / neoplasm
  • Psammomatous somatostatinoma

Diagnostic Criteria

  • Nearly all intestinal cases located in or near ampulla of Vater
  • Uniform cells with bland round regular nuclei
    • Few mitotic figures
    • Slightly granular, pale eosinophilic cytoplasm
  • Tubular and glandular architectural pattern usually predominates
    • May also have insular and trabecular patterns
  • Psammoma bodies in glandular spaces in half of cases
  • Somatostatin stain diffusely positive
  • Somatostatinoma syndrome seen only in rare patients
    • Diabetes mellitus, steatorrhea, cholelithiasis
  • About half of cases associated with neurofibromatosis type 1
    • Pheochromocytoma frequently associated in such cases
    • Same behavior as sporadic cases
  • Rare cases reported associated with MEN1 syndrome
  • Invades locally and may metastasize
    • Duodenal wall, pancreas
    • Local node metastases (35%)
    • Metastases to liver (10%) and very rarely beyond
  • In spite of spread, after debulking, we are not aware of any reported cases of disease progression and/or death
  • Note that about half of somatostatinomas arise instead in the pancreas with a different biology
    • Frequently demonstrates somatostatinoma syndrome, metastases and mixed secretory products
    • Infrequently associated with neurofibromatosis type 1 or psammoma bodies
    • 50% 10 year survival
  • Rare cases reported elsewhere in and out of GI tract

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting/updates: 7/27/10, 12/24/11, 3/10/12

Supplemental studies

  • Somatostatin stain diffusely positive
    • (Scattered somatostatin positive cells may be seen in other neuroendocrine neoplasms)
    • May also have focal cells positive for calcitonin, pancreatic polypeptide, ACTH, gastrin, serotonin
    • Synaptophysin usually positive
      • Chromogranin variable, may be negative
    • Argyrophil variable, argentaffin negative
    • PASd stains luminal border and secretions but not cytoplasm


WHO 2010 recommends the following grading scheme, but it is not clear if it applies to somatostatinomas

    Proposed grading scale based on proliferation

    Grade Mitotic count per 10 hpf % of cells Ki67+
    G1 <2 ≤2
    G2 2-20 3-20
    G3 >20 >20
    • Mitotic counts based on 50 hpf
    • Ki67 % based on 500-2000 cells
    • If discrepant, use higher grade
    • Scale proposed by European Neuroendocrine Society (ENETS)
      • Carcinoids / neuroendocrine tumors may be G1 or G2
      • G3 is definitional for high grade neuroendocrine carcinoma
    • Progression from G1/2 to G3 is quite rare
      • G3 appears to be a separate process

    Grading/Staging References

    • Rindi G, Klöppel G, Couvelard A, Komminoth P, Körner M, Lopes JM, McNicol AM, Nilsson O, Perren A, Scarpa A, Scoazec JY, Wiedenmann B. TNM staging of midgut and hindgut (neuro) endocrine tumors: a consensus proposal including a grading system. Virchows Arch. 2007 Oct;451(4):757-62.
    • Rindi G, Klöppel G, Alhman H, Caplin M, Couvelard A, de Herder WW, Erikssson B, Falchetti A, Falconi M, Komminoth P, Körner M, Lopes JM, McNicol AM, Nilsson O, Perren A, Scarpa A, Scoazec JY, Wiedenmann B; and all other Frascati Consensus Conference participants; European Neuroendocrine Tumor Society (ENETS). TNM staging of foregut (neuro)endocrine tumors: a consensus proposal including a grading system. Virchows Arch. 2006 Oct;449(4):395-401.
  • Staging
    • Use TNM
  • Differential Diagnosis

    Duodenal (Psammomatous) Somatostatinoma Duodenal or Ampullary Adenocarcinoma
    Round regular nuclei Nuclear atypia and pleomorphism
    Very low mitotic rate Mitotic rate may be moderate to high, may have atypical forms
    May have insular or trabecular pattern Insular and trabecular patterns unusual
    Not associated with overlying adenoma May be associated with overlying adenoma
    50% have psammoma bodies Psammoma bodies not seen
    Somatostatin diffusely positive Somatostatin negative
    Synaptophysin usually positive, chromogranin may be positive Synaptophysin, chromogranin negative
    The frequent glandular pattern and invasion seen in somatostatinomas make this a more difficult distinction than for many other well differentiated gi endocrine neoplasms


    Gastrointestinal Endocrine Cell Proliferations and Neoplasms


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    • Bosman FT, Carneiro F, Hruban RH, Thiese ND (Eds). WHO Classifiication of Tumors of the Digestive System, IARC, Lyon 2010
    • Burke AP, Sobin LH, Shekitka KM, Federspiel BH, Helwig EB. Somatostatin-producing duodenal carcinoids in patients with von Recklinghausen's neurofibromatosis. A predilection for black patients. Cancer. 1990 Apr 1;65(7):1591-5.
    • Williams GT. Endocrine tumours of the gastrointestinal tract-selected topics. Histopathology. 2007 Jan;50(1):30-41.
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    • Bettini R, Falconi M, Crippa S, Capelli P, Boninsegna L, Pederzoli P. Ampullary somatostatinomas and jejunal gastrointestinal stromal tumor in a patient with Von Recklinghausen's disease. World J Gastroenterol. 2007 May 21;13(19):2761-3.
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    • Nesi G, Marcucci T, Rubio CA, Brandi ML, Tonelli F. Somatostatinoma: clinico-pathological features of three cases and literature reviewed. J Gastroenterol Hepatol. 2008 Apr;23(4):521-6.
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