Malignant small bowel gastrointestinal stromal tumor with multiple rare metastases – a case report

Abstract

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms with uncertain prognosis. Distant metastases are most commonly found in the liver, followed by the lungs and bones. We report one case of a 50-year-old female who presented with diffuse abdominal pain. Ultrasonography showed small bowel obstruction by a lesion of 10 cm in diameter. Segmental jejunal resection was performed with removal of a well-circumscribed submucosal mass, with solid and cystic areas and foci of hemorrhage. Surgery also revealed a nodule in the recto-uterine pouch, a firm tumor in the left ovary, and multiple diffuse nodules in the omentum. Histopatho-logical examination showed mixed pattern of spindle and epithelioid cells, with dense cellularity, high nuclear pleomorphism, 2 mitoses per 50 high-power fields, necrosis and rich vascularization. Immunohistochemical analysis showed diffuse positive staining for CD 117 and VIM. Tumor cells were consistently negative for actin, CD34 and S-100. Based on the above findings, the diagnosis was mixed type malignant GIST of the small intestine with multiple metastases in the pouch of Douglas, ovary and omentum. Histologic subtype, tumor size and site are the most important features in malignant behavior. Mitotic count proved to be less significant. Making the right diagnosis is crucial for patients.