Stomach
Stromal / other tumors
Gastroblastoma
Author: Diana Agostini-Vulaj, D.O.
Editor-in-Chief: Debra L. Zynger, M.D.
Topic Completed: 11 November 2019
Minor changes: 2 September 2020
Copyright: 2019-2021, PathologyOutlines.com, Inc.
PubMed Search: Gastroblastoma
Table of Contents
Definition / general | Essential features | ICD coding | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Diagnosis | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Clinical images | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Electron microscopy images | Molecular / cytogenetics description | Molecular / cytogenetics images | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Agostini-Vulaj D. Gastroblastoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stomachgastroblastoma.html. Accessed January 24th, 2021.
Definition / general
- Rare biphasic tumor of the stomach (only 13 cases currently reported) (Histopathology 2019;75:778)
Essential features
- Rare biphasic tumor of stomach with epithelial and stromal elements
- Characteristic fusion gene, MALAT1-GLI1
- Mostly seen in young adults
ICD coding
- ICD-O: 8976 / 1
Epidemiology
- Young adults, most < 30 years of age but also seen in older adults; M > F (Histopathology 2019;75:778, Mod Pathol 2017;30:1443)
Sites
- Stomach, antrum > body (Histopathology 2019;75:778)
Pathophysiology
Etiology
- Unknown at this time
Clinical features
- Nonspecific symptoms at presentation (Am J Surg Pathol 2009;33:1370, Radiographics 2014;34:1929)
Diagnosis
- Imaging followed by tissue diagnosis
Radiology description
- CT: solid and cystic heterogenous mass centered in gastric wall or exophytic (Radiographics 2014;34:1929)
Radiology images
Images hosted on other servers:
CT and MRI with multilobulated cystic mass
Prognostic factors
- Unknown at this time
Case reports
- 9 year old boy with abdominal pain and periumbilical mass (J Clin Pathol 2010;63:270)
- 12 year old boy with blood in stool and gastric mass (Int J Clin Exp Pathol 2014;7:3380)
- 29 year old woman with epigastric pain (Int J Surg Case Rep 2017;39:72)
Treatment
- Surgical resection; some reported cases received adjuvant radiation treatment as well (Am J Surg Pathol 2009;33:1370, J Clin Pathol 2010;63:270)
Clinical images
Images hosted on other servers:
Lobulated stomach mass
Gross description
- Multinodular / multilobated gastric mass originating from gastric wall
- Pink-tan, slightly hemorrhagic cut surfaces
- Size range 3.5 - 15 cm (Am J Surg Pathol 2009;33:1370, Mod Pathol 2017;30:1443, Radiographics 2014;34:1929)
Gross images
Images hosted on other servers:
Solid and cystic mass
Variegated mass
Transmural mass
Microscopic (histologic) description
- Biphasic tumor
- Spindle cell component demonstrating sheets of monotonous spindled type cells
- Epithelial component demonstrating cords / clusters of epithelial type cells, some with vague to well-formed gland formation, which may contain inspissated material
- Relatively low mitotic rate (Am J Surg Pathol 2009;33:1370)
Microscopic (histologic) images
Contributed by Raul S. Gonzalez, M.D. and Rondell P. Graham, M.B.B.S.
Invasive tumor
Epithelial component
Nests of epithelioid cells
Spindle cell component
Positive stains
Negative stains
- Epithelial component: CK5 / 6, CK20, EMA
- Both components: CD34, CD99, ER, KIT, SMA, desmin, S100, p63, calretinin, chromogranin, synaptophysin, CDX2 and TTF1 (Am J Surg Pathol 2009;33:1370)
Electron microscopy description
- Tumor cells are joined by desmosomes and have microvilli (J Clin Pathol 2010;63:270)
Electron microscopy images
Images hosted on other servers:
Desmosomes and 
microvilli between 
tumor cells
Molecular / cytogenetics description
- Characterized by MALAT1-GLI1 fusion gene (Mod Pathol 2017;30:1443)
Molecular / cytogenetics images
Images hosted on other servers:
RT-PCR, MALAT1-GLI1 fusion and sequencing
GLI1 FISH
breakapart and
MALAT1-GLI1
fusion FISH
Sample pathology report
- Stomach, partial gastrectomy:
- Gastroblastoma (see comment)
- Comment: H&E sections demonstrate a biphasic tumor with varied intermixed epithelial and stromal elements. The epithelial component is positive for cytokeratin AE1 / AE3 while the stromal component is positive for vimentin. Both components are negative for c-KIT, CD34, desmin, S100, CD99 and SMA. Additional ancillary testing demonstrates the MALAT1-GLI1 fusion gene.
Differential diagnosis
- Biphasic synovial sarcoma
- Usually monophasic in stomach (Am J Surg Pathol 2009;33:1370)
- Translocation t(x;18), SYT-SSX1
- Carcinosarcoma
- Overtly malignant epithelial and stromal tumor
- No characteristic translocation
- Gastrointestinal stromal tumor (GIST)
Board review style question #1
Which fusion gene typifies gastroblastoma?
- ASPL-TFE3
- BRAF-KIAA1549
- ETV6(TEL)-NTRK3
- MALAT1-GLI1
- SYT-SSX1
Board review style answer #1
Board review style question #2
A large gastric antral tumor is excised in a 15 year old male. Histologically you identify 2 differing cellular components, with spindled and epithelioid morphology (see images below). c-KIT, DOG1, SMA, desmin and S100 are negative. This could be which tumor?
- Gastroblastoma
- Gastrointestinal stromal tumor
- Granular cell tumor
- Leiomyoma
- Schwannoma
Board review style answer #2
