FOR US RESIDENTS ONLY
Send Email  SEND TO A COLLEAGUE   |   Print this page   PRINT PAGE   |  A A A
Healthcare Professionals  |
INFORMATION FOR
KIT+ GIST PATIENTS >
GIST Treatment Healthcare Professional
Kit+ Gastrointestinal Stromal Tumor
(Kit+ GIST) Diagnosis
View Chart

Initial Presentation

Many patients with KIT+ GIST are asymptomatic in the early stages, so diagnosis may follow the identification of lesions as the result of unrelated radiographic imaging, endoscopy, or surgeries.1,2 In a population-based study of GISTs in Sweden, 69% (199/288) of GISTs were detected as a result of symptoms, 21% were detected when the patients underwent surgery for other causes, and 10% were identified at autopsy.3

As the disease progresses, symptoms may increase in intensity and may include: 4,5

  • Abdominal discomfort or pain
  • Sense of abdominal fullness
  • Nausea
  • Vomiting
  • GI bleeding
  • Fatigue related to anemia
  • Anorexia
  • Weight loss
  • Urinary problems

Patients with possible GIST often present at the emergency room with a suspicious large mass (abdominal swelling, upper GI bleeding).1


Diagnostic Workup

Initial workup in a patient with suspected GIST includes history and physical examination, endoscopy (for primary gastric mass), endoscopic ultrasound, liver function testing, and complete blood counts. Computed tomography (CT) and, occasionally, magnetic resonance imaging (MRI) are used to evaluate abdominal masses or nonspecific symptoms.1

Surgical assessment is often necessary to determine tumor resectability and possible metastatic disease.1

Because KIT(CD117) is expressed in nearly all GISTs, KIT staining is commonly used to make an accurate diagnosis and get the patient started on needed treatment. About 5% of GISTs, however, are KIT-negative. Diagnosis of these tumors is difficult and should be referred to a pathologist with the appropriate expertise.1


  • Most GISTs occur in 2 major patterns: spindle cell (70%) and epithelioid (20%); the remainder consists of a mixture of these cell types. Spindle-cell GIST resembles other smooth-muscle sarcomas (eg, leiomyosarcoma and leiomyoma), which can make it difficult to accurately identify1
  • KIT is the most common tumor marker for GIST, with 95% of GISTs staining positive for KIT2
Common Histologic Appearances of GIST http://www.annualreviews.org
Differential Diagnosis of GIST by Immunophenotype1,3
Tumor
CD117 (KIT)
CD34
SMA
Desmin
S-100
GIST
+++
Diffuse
(>95%)
strong
++
(60% -70%)
+
(30% -40%)
-
(rare)
+/-
(5%)
Smooth Muscle Tumors
leiomyosarcoma leiomyoblastoma leiomyoma/leioma
(rare) focal (<5%)
+
(10% -15%)
+
+
-
(rare)
Schwannoma
(rare)
focal (<5%)
+
-
-
+

  1. Demetri GD, Benjamin RS, Blanke CD, et al. NCCN task force report: management of patients with gastrointestinal stromal tumor (GIST)—update of the NCCN clinical practice guidelines. J Natl Compr Canc Netw. 2007;5(suppl2):S1–S29.

  2. Eisenberg BL, Judson I. Surgery and imatinib in the management of GIST: Emerging Approaches to adjuvant and neoadjuvant therapy. Ann Surg Oncol. 2004;11(5):465-475.

  3. Nilsson B, Bumming P, Meis-Kindblom JM, et al. Gastrointestinal stromal tumors: the incidence, prevalence, clinical course, and prognostication in the preimatinib mesylate era – a population-based study in western Sweden. Cancer. 2005; 103(4):821–9.

  4. Griffin JM, St Amand M, Demetri GD. Nursing implications of imatinib as molecularly targeted therapy for gastrointestinal stromal tumors. Clin J Oncol Nurs. 2005;9(2):161-169.

  5. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: soft tissue sarcoma. V.2.2007

ENROLL NOW

Enroll in the
GIST Registry, an
observational database
designed to collect data
on patients on GIST.

 
 
Learn More About
GIST Registry
Radiologic Evaluation Of GIST
Related Information