Synchronous mucosa-associated lymphoid tissue lymphoma and gastrointestinal stromal tumor of the stomach presenting with gastric bleeding.

We report an extraordinarily rare case of synchronous mucosa-associated lymphoid tissue lymphoma and gastrointestinal stromal tumor of the stomach. An 80-year-old man presented with gastric bleeding. Gastroscopy showed an ulcerative lesion and a submucosal tumor at the upper corpus of the stomach. The ulcerative lesion was proven by biopsy to be mucosa-associated lymphoid tissue lymphoma, but the submucosal tumor could not be diagnosed. Due to the repeating episodes of massive gastric bleeding, a total gastrectomy with lymphadenectomy was performed. After the operation, the submucosal tumor was pathologically proven to be a gastrointestinal stromal tumor. In this case, synchronous occurrence of mucosa-associated lymphoid tissue lymphoma and gastrointestinal stromal tumor seems to be coincidental rather than related with the same pathogenic triggering. Surgical resection of the stomach provided an accurate diagnosis and an effective treatment.