Metachronous extragastrointestinal stromal tumor (EGIST) in utero: Report of an unusual case

The gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the digestive tract. Currently, GIST is the name given to CD117 positive mesenchymal tumors, primary of the digestive tract, mesentery, and retroperitoneum. Nevertheless, they have been reported in the mesentery, omentum, gallbladder, bladder wall, and few cases in the uterus; known as extragastrointestinal stromal tumors (EGIST).

Seventy-six-year-old woman with a history of the third recurrence of pelvic tumor located in the uterus initially diagnosed as uterine leiomyosarcoma. CT and MRI showed a tumor in the uterine corpus of approximately 10 cm. It was decided to perform the surgical rescue. The immunohistochemistry and anatomic pathology report revealed a tumor compatible with a uterine EGIST. It was decided to perform adjuvant treatment with imatinib. Currently, the patient continues to be disease-free 20 months after the surgery.

For years, GIST has often been confused with leiomyosarcoma, given that they are histologically almost indistinguishable. The IHC analysis for KIT (CD117) has become essential in the GIST diagnosis. On the other hand, stromal tumors arising outside the gastrointestinal tract are rare (5%), which have a histological and biological behavior similar to that of GISTs.

EGISTs are extremely rare and often incidentally detected. Currently, evidence about this location is scarce. According to the literature, this is the first case of uterine EGIST with a metachronous presentation.