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Updated: May 11, 2026

Molecular and Immunologic Techniques in a Genetically Engineered Mouse Model of Gastrointestinal Stromal Tumor
Published on: May 2, 2022
Primary extragastrointestinal stromal tumors: a clinicopathological and immunohistochemical study - a tertiary care
R Patnayak1, A Jena, S Parthasarathy
1Department of Pathology, Sri Venketeswar Institute of Medical Sciences, Tirupati, Andhra Pradesh 517 507, India.
Background:
Extra gastrointestinal stromal tumors (EGIST) are uncommon compared to their gastrointestinal counterparts. EGISTs involve omentum, mesentery, retroperitoneum, pancreas, and pelvis.
Materials And Methods:
Ten EGISTs were analyzed in this study from January 1995 to November 2011. They were analyzed with respect to clinical features, imageological, histopathological, and immunohistochemical findings. The immunohistochemical stains used were Smooth muscle actin (SMA), Desmin, S-100 protein, CD34 and CD-117.
Results:
There was slight female preponderance with wide age range. Four of the tumors were in retroperitoneum, three in mesentery, and two in omentum and one in pelvis. Histopathologically majority were spindle cell tumors. Immunohistochemically CD117 was consistently positive followed by CD34. Smooth muscle actin was positive in eight cases, S-100 protein and desmin were positive in two cases each.
Conclusion:
EGISTs are rare and should be considered in the differential diagnosis of the mesenchymal tumors and immunohistochemistry helps to confirm the diagnosis. Further study with better follow-up is desired to characterize these uncommon tumors.
