Late recurrence (33 years) of a gastric epithelioid stromal tumor (leiomyoblastoma) with low malignant potential.

A recurrence of a gastric epithelioid stromal tumor (leiomyoblastoma) 33 years after incomplete resection and radiation therapy is reported. The original tumor involved the posterior gastric wall and presented with intraperitoneal hemorrhage. A tumor recurrence was found attached to the stomach with invasion through the wall of the splenic flexure of the colon. The histologic features of the tumor had not significantly altered, except for a slight increase in mitotic rate. Neither the original tumor nor the recurrence exhibited smooth-muscle differentiation on ultrastructural or immunohistochemical examination, suggesting an origin from an undifferentiated or primitive mesenchymal cell. The term leiomyoblastoma, although established in the literature, should be reserved for epithelioid tumors in which myoid differentiation can be established. The long interval to recurrence supports the suggestion that all of these tumors have at least a low-grade malignant potential.