The case history of a 53-yr-old woman exhibiting the progressive appearance of several hundreds of subcutaneous leiomyomatous tumors in a 15-yr period is presented. The occurrence of multiple tumors in the gastrointestinal tract, mesentery, and retroperitoneum, necessitated several laparotomies because of pain and chronic blood loss. On light microscopy high mitotic activity, which is generally a characteristic of sarcoma, was only encountered in lesions, surgically removed a few months before death. It is argued that our patient suffered from multiple leiomyomatous tumors with progressive growth capacity, which may represent a multifocal origin rather than a metastasized sarcoma.