Stanford School of Medicine

Surgical Pathology Criteria

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  • Biphasic epithelial-mesenchymal tumor of the stomach

Diagnostic Criteria

  • One report of three cases to date (Miettinen)
    • One additional case report (Shin)
  • Two components: mesenchymal and epithelial
    • May be sharply or indistinctly demarcated
    • Diffuse sheets of uniform oval to spindled cells
    • Clusters and cords of epithelioid cells
      • Occasional small gland formation by epithelioid cells in a field of spindled cells
  • Mitotic rates observed: 0, 0, 4, 30 / 50 hpf
  • All cases to date in young adults and one 9 year old
  • Robert V Rouse MD
    Department of Pathology
    Stanford University School of Medicine
    Stanford CA 94305-5342

    Original posting/updates: 2/4/10, 11/27/11


Supplemental studies


  • Epithelioid cells
    • Positive for keratins AE1/3, CK18, focally for CK7
    • Negative for CK5/6, CK20, EMA
  • Spindle cells CD10 strong positive
  • Both populations negative for: CD34, CD99, ER, CKIT, Smooth muscle actin, Desmin, S100, p63, Calretinin, Chromogranin, Synaptophpysin, CDx2 and TTF1
  • (One case report of CD56 and CKIT positive epithelioid cells with only focal CD10 staining of stroma)

Genetic Studies

  • FISH negative for SS18 (marker of synovial sarcoma)


Differential Diagnosis

Gastroblastoma Carcinosarcoma
Young adults Generally older patients
Cytologically bland Malignant epithelial and stromal elements

Gastroblastoma Gastric Synovial Sarcoma
Components may be indistinct Components generally distinct
FISH negative for SS18 abnormalities FISH shows evidence of SS18 rearrangement

Gastroblastoma Gastric Teratoma
Young adults Generally infants
Only two components Multiple tissue types

Gastroblastoma Mesothelioma
Negative for CK5/6 and calretinin CK5/6 and calretinin positive
Not serosal based Based in serosa


  • All cases ≤30 to date
    • 9-30
  • All alive without disease
    • 3.5-14 years follow up


  • Miettinen M, Dow N, Lasota J, Sobin LH. A distinctive novel epitheliomesenchymal biphasic tumor of the stomach in young adults ("gastroblastoma"): a series of 3 cases. Am J Surg Pathol. 2009 Sep;33(9):1370-7.
  • Shin DH, Lee JH, Kang HJ, Choi KU, Kim JY, Park do Y, Lee CH, Sol MY, Park JH, Kim HY, Montgomery E. Novel epitheliomesenchymal biphasic stomach tumour (gastroblastoma) in a 9-year-old: morphological, ultrastructural and immunohistochemical findings. J Clin Pathol. 2010 Mar;63(3):270-4.
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