Gastrointestinal Stromal Tumor - Stomach

An ulcerated GIST originating in the muscle layer. The tumor was positive for CD117 (c-kit), CD34, and SMA (focally). It was negative for S-100 protein, ruling out a schwannoma. A more recently described immunostain, DOG-1, is considered quite specific for GIST. Image Copyright: pathorama.ch.