Korean J Pathol.  2001 Aug;35(4):347-350.

Primary Extragastrointestinal Stromal Tumor (EGIST) of the Greater Omentum

• Choi KU
• Kim JY
• Park DY
• Lee CH
• Sol MY
• Suh KS
• Lee JW

Abstract

Gastrointestinal stromal tumors (GISTs) were recently defined as spindle cell, epithelioid, or occasionally, pleomorphic mesenchymal tumors of the gastrointestinal tract that express the CD117 (proto-oncogene c-kit protein, stem cell factor receptor), as detected using immunohistochemistry. And they show a new tendency to include the CD117-positive mesenchymal spindle cell or epithelioid neoplasms primary in the omentum and mesentery, and is so termed extragastrointestinal stromal tumors (EGISTs). Omental EGISTs are very rare and similar to their gastrointestinal counterpart. We present a case of primary EGIST of the greater omentum in a 58-year-old man. The resected tumor mass measured 20X15X5 cm and weighed 1,150 g. The cut surface displayed a central cystic change and partial mural nodules. Microscopically, most parts of the tumor were composed of round or polygonal cells, with many of them containing perinuclear vacuoles. The mitotic count was less than one per 50 high-power-fields. Immunohistochemically, the tumor cells were diffusely positive for CD117 and vimentin, and focally for smooth muscle actin and CD34. Ultrastructurally, partially smooth muscle differentiation was confirmed in this case.

Keyword

Extragastrointestinal stromal tumor; Omentum; Proto-oncogene protein c-kit

MeSH Terms

Actins
Epithelioid Cells
Gastrointestinal Stromal Tumors
Gastrointestinal Tract
Humans
Immunohistochemistry
Mesentery
Middle Aged
Muscle, Smooth
Omentum*
Proto-Oncogene Proteins c-kit
Stem Cell Factor
Vacuoles
Vimentin
Actins
Proto-Oncogene Proteins c-kit
Stem Cell Factor
Vimentin