ATYPICAL LOCATION OF A STROMAL CELL CARCINOMA IN THE RECTAL wALL - A CASE REPORT

Summary Gastrointestinal stromal tumours (GIST) are rare proliferative lesions arising from the mesenchyme. In the United States, there are approximately 5000 cases diagnosed per year. The incidence of GISTs in males and females is equal. Only in about 5% of the cases, these lesions occur in the large intestine – whether in the submucosal, intramural or subserosal location. Approximately 10-30% of the GISTs have an asymptomatic course, and are incidentally diagnosed during imaging or surgical procedures performed for other indications. This article presents the case of a 74-year old female, who was found to have a stromal tumor in the wall of the rectum. The initial diagnosis was based on a proctological examination, anorectal endosonography and computed tomography. The final diagnosis was established based on histological analysis of material obtained via core-needle biopsy. The patient was referred to the Institute of Oncology, where she was qualified for neoadjuvant therapy, and later underwent surgery. A two-year observation period did not reveal any local recurrence or distant metastases. GISTs occur very rarely in the rectum and thus pose a diagnostic challenge. Endosonography and computed tomography are useful in determining the location of the tumor with respect to the pelvic structures. The final diagnosis rests upon histopathological and immunohistochemical analysis of material obtained via core-needle biopsy.