Jejunal Leiomyoma Vis-À-Vis Jejunal Gist – Rare Mesenchymal Mimics & Role of Immunohistochemistry (Ihc) in Proper Diagnosis : A Case Report

Mesenchymal tumours of GI tract represent a heterogenous group of neoplasms encompassing benign , intermediate, and malignant entities. In consideration of their rarity as well as of intrinsic complexity, diagnostic accuracy represents a major challenge. Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal (GI) tract. GISTs account for approximately 80% of the clinically relevant GI mesenchymal tumors. They are basically positive for KIT by immunohistochemistry. Almost all GISTs are negative for desmin, which is a positive marker for mature smooth muscle cells. Smooth muscle tumors such as leiomyomas and leiomyosarcomas, which usually show the spindle cell morphology, consist of approximately 10% of the clinically relevant GI mesenchymal tumors and are almost positive for desmin and negative for KIT. Thus, most GI mesenchymal tumors are differentially diagnosed by immunohistochemistry (IHC) of KIT, desmin.