Gastrointestinal stromal tumors - a clinical-morphological study on 15 cases

The authors present their experience in addressing the gastrointestinal stromal tumors (GIST).

15 GISTs operated in the last five years (2008-2013) were analyzed.

The preoperative diagnosis was difficult: established by clinical examination and CT in two cases; imagistic accidental discovery in four cases and revealed by evolving complications in nine cases (gastrointestinal bleeding in four cases and bowel obstruction in five cases). CT may be useful in the preliminary estimation of the tumor extent. Tumor location was: stomach four, duodenum one, small bowel seven, and colon three. Pathological examination set the main criteria for assessing the risk of recurrence and indication for adjuvant therapy: the tumor size, the histological type (spindle cell nine, epithelioid four, and mixed two) and the mitosis rate, while the immunohistochemistry examination established the correct diagnosis (positivity for CD117 and CD34) and criteria of aggressiveness (positivity for Ki67). All cases were operated, the surgical procedure being chosen according to the tumor location and stage. Adjuvant therapy with Imatinib 400 mg/day was performed in the 12 cases with high risk of recurrence. The therapeutic outcome was: a postoperative morbidity rate of 13.3%, four patients cured, one local recurrence under Imatinib therapy, a mortality rate of 6.6% and 10 patients in different phases of adjuvant therapy.

GIST has been imposed over the last decade as the main type of non-epithelial tumor of the digestive tract. The preoperative imagistic investigations can be very useful for setting the surgical strategy. The improvement of the mitotic index and/or Ki67 labeling index (LI) determination could render more accurate the scales for prognostic assessment. The two steps algorithm - surgery + adjuvant therapy - still remains the only option to make this dangerous condition a curable one.