Malignant stromal tumor consistent with fibrosarcoma arising from Meckel's diverticulum. Clinicopathological study of an incidentally discovered tumor and review of the literature.

The authors report a case of a Meckel's diverticulum mesenchymal tumor incidentally discovered in a 69-year-old woman undergoing laparotomy for an ovarian cyst. Histological examination of the tumor revealed a fasciculated proliferation of spindle cells that proved to be immunoreactive to vimentin only; pleomorphism was mild, necrosis extensive and mitotic count high. Because these features were consistent with those of fibrosarcoma, the tumor was classified in the category of gastrointestinal stromal tumors; more specifically, it was considered malignant for the presence of spread beyond the primary site in the form of peritoneal nodules and for the high mitotic count. We have been able to find only one previously reported case of mesenchymal malignant tumor of Meckel's diverticulum classified as fibrosarcoma among the 199 malignant tumors described in the literature. Based on this personal experience and on the review of the literature concerning malignant tumors of Meckel's diverticulum, we discuss both the rarity of these tumors and the importance of removing Meckel's diverticulum every time it is found during laparotomy.