Orbital metastasis from a gastrointestinal stromal tumor: A case report.

BACKGROUND: Gastrointestinal stromal tumor (GIST) is the most common primary mesenchymal tumor. The most common metastasis sites are the liver and the surface of the peritoneum. In this study, we present a case of orbital GIST metastasis. CASE PRESENTATION: A 43-year-old woman who had a history of small intestinal stromal tumor 4 years ago suffered GIST metastasis to the left orbit. MRI confirmed the presence of a lacrimal gland lesion with isointense on T1 and hyperintense on T2 weighted images. Histopathology analysis of the tumor showed predominantly spindle or oval cells with nuclear pleomorphism and increased mitoses. The tumor also stained positive for c-KIT (CD117) upon immunochemistry, confirming the diagnosis. CONCLUSIONS: GISTs typically occur as sporadic solitary tumors, and their common metastasis sites are the liver and the surface of the peritoneum. Orbital involvement is extremely rare. The orbital GIST metastatic tumor has special imaging properties, as evidenced by histopathology, immunochemistry, and magnetic resonance imaging (MRI).