Other tumors

Gastrointestinal stromal tumor

Topic Completed: 1 August 2013

Minor changes: 20 September 2021

Copyright: 2003-2021,, Inc.

PubMed Search: Gastrointestinal stromal tumor esophagus free full text[sb]

Feriyl Bhaijee, M.D.
Israh Akhtar, M.D.
Page views in 2020: 2,448
Page views in 2021 to date: 1,519
Cite this page: Bhaijee F, Akhtar I. Gastrointestinal stromal tumor. website. Accessed October 20th, 2021.
Definition / general
  • Mesenchymal tumor of digestive tract, likely originating from multipotential progenitors of interstitial cells of Cajal
  • Microscopic GIST: sporadic interstitial cell of Cajal hyperplasia, seedling GIST, minimal GIST
  • Very rare: < 3% of all GIST arise in esophagus
  • No gender predilection
  • Wide age range, average 50 - 60 years
  • May be incidental finding in patients undergoing resection of upper GI neoplasms (Can J Surg 2012;55:366)
  • Mid to lower esophagus
  • Mostly sporadic
  • Higher incidence in patients with
    • Neurofibromatosis type I (NF1, von Recklinghausen disease)
    • Carneys triad
  • Familial GIST syndrome: rare, autosomal dominant genetic disorder, characterized by germline KIT or PDGFRA mutations, early onset of multiple GIST tumors, skin pigmentation abnormalities (Am J Surg Pathol 2013;37:898)
Clinical features
  • Esophageal mass, stricture, perforation
  • Dysphagia
  • Metastatic spread to liver and peritoneum
  • Biopsy with immunohistochemical / molecular confirmation
Radiology description
  • CT / MRI: useful for preoperative and metastatic evaluation
  • PET: FDG avidity
    • Used to monitor response to tyrosine kinase inhibitor therapy
  • Barium studies: smooth intraluminal mass or large ulcerative mass extending intraluminally
  • Endoscopic ultrasound: enables image guided core needle biopsy or fine needle aspiration
Radiology images

Images hosted on other servers:

40 year old man with dysphagia

Enhancing chest CT

CT scan shows well circumscribed tumor

Prognostic factors
  • Risk stratification based on size and mitotic activity per 50 high power fields (HPF):
    • Low risk: < 5 cm and < 5/50 HPF
    • Intermediate risk: < 5 cm and 6 - 10/50 HPF OR 5 - 10 cm and < 5/50 HPF
    • High risk: > 5 cm and > 5/50 HPF OR > 10 cm and any mitotic rate OR any size and > 10/50 HPF

Risk category Tumor size Mitotic rate/50 HPF
Low < 5 cm < 5
Intermediate < 5 cm 6 - 10
Intermediate 5 - 10 cm < 5
High > 5 cm > 5
High > 10 cm Any mitotic rate
High Any size > 10
Case reports
  • Surgical resection
  • Neoadjuvant small molecule tyrosine kinase inhibitors: imatinib mesylate (STI571, Gleevec), sunitinib maleate
Clinical images

Images hosted on other servers:

Endoscopic image

Gross description
  • Lobulated, well circumscribed mass with fleshy cut surfaces
  • Cystic degeneration, necrosis, hemorrhage common
  • Overlying esophageal mucosa may be ulcerated
Gross images

Images hosted on other servers:

19 cm tumor with cystic degeneration and necrosis

well circumscribed
mass in posterior

Microscopic (histologic) description
  • Histologic heterogeneity:
    • Spindle cell type (70%): relatively uniform eosinophilic cells in short fascicles or whorls, indistinct cell borders, paranuclear cytoplasmic vacuoles, stromal lymphocytes and microcystic stromal degeneration (as in schwannoma), minimal collagen, delicate thin walled vessels, stromal hemorrhage
    • Epithelioid type (20%): rounded cells with variably eosinophilic or clear cytoplasm in nests or sheets, uniform round / ovoid nuclei with vesicular chromatin
    • Mixed type (10%): may have abrupt transition between spindle cell and epithelioid areas or complex comingling of both
  • Stromal skeinoid fibers (< 20%): hyaline or fibrillary brightly eosinophilic PAS+ structures, representing nodular tangles of collagen fibers; more common in small bowel GIST
  • Rarely: cytologic atypia, myxoid stroma
  • Variable mitotic activity
  • Microscopic GIST: < 1 cm, spindle cells with hyalinized stroma and variable calcification (Pathology 2008;40:9)
Microscopic (histologic) images

Images hosted on other servers:

Dense cellularity, mixture of epithelioid and spindled areas

Intramural nodule
and fascicular
arrangement of
spindle cells



KIT / CD117

CD117 and desmin

CD117, CD34, SMA, S100

Cytology description
  • Cellular monomorphic proliferations of epithelioid or spindle cells
    • Round / oval nuclei, vesicular chromatin, fibrillary cytoplasm
  • Cohesive fragments with admixed delicate, thin walled vessels
  • Features of malignancy: cellular dyscohesion, nuclear pleomorphism, prominent nucleoli, increased mitotic activity, prominent necrosis
Cytology images

Images hosted on other servers:

Spindle cells with high cellularity

Epithelioid cells with round nuclei

Positive stains
Negative stains
Electron microscopy description
  • Relative lack of differentiation
    • Incomplete smooth muscle or neuroaxonal differentiation
    • No bundles of actin filaments (seen in true smooth muscle tumors)
Electron microscopy images

Images hosted on other servers:

demonstration of
cytoplasmic vesicles
in high risk GIST

Molecular / cytogenetics description
  • Mutually exclusive mutations of activating KIT (95%) or platelet derived growth factor alpha (PDGFRA) receptor tyrosine kinase (5%)
    • In frame deletions, point mutations, duplications, insertions
    • Most common: KIT juxtamembrane domain (exon 11) mutations
      • Confers better response to tyrosine kinase inhibitor therapy
Differential diagnosis
Back to top
Image 01 Image 02