Gastrointestinal stromal tumor: a rare case of ovarian involvement

Gastrointestinal stromal tumors are the most common mesenchymal tumors of the gastrointestinal tract. However, they account for 1–2% of all gastrointestinal neoplasms. These tumors are derived from the interstitial cells of Cajal in the gastrointestinal tract. They occur mainly in the stomach (60%), small bowel (25%), colon and rectum (10%), and in other locations (5%). 2 The main sites of metastasis are the liver, omentum, peritoneum, and rarely in bone, lymph nodes, subcutaneous tissue, and lungs. Most gastrointestinal stromal tumors harbor activating mutations in the KIT or PDGFRA genes. When these tumors arise in atypical locations outside of the gastrointestinal tract they are referred to as extragastrointestinal stromal tumors; the omentum, mesentery, and retroperitoneum are the main sites involved. Ovarian involvement is very rare and occurs secondary to metastatic spread from a sometimes occult extraovarian primary site. The first report was made by Zighelboim et al. The diagnosis of both gastrointestinal stromal tumor and extragastrointestinal stromal tumor rely on histology and immunohistochemistry. In the macroscopic pathology, most gastrointestinal stromal tumors have an exophytic growth, with a wellcircumscribed, ulcerated, and hemorrhagic mass (Figure 1). Histologically, these tumors are characterized by a proliferation of cells that can have spindled (most commonly), epithelioid, or mixed epithelioid and spindled morphology. The spindled variant typically demonstrates bland cytology with inconspicuous nucleoli and pale pink cytoplasm—nuclear palisading and paranuclear vacuolization is not uncommon (Figure 2). The epithelioid variant demonstrates round