In medical oncology,<unk> s <unk> s) are rare tumors of the<unk>  tract.<unk> s are non-epithelial tumors and mostly occur in the stomach (70% of cases). In 1983, Mazur and Clark and Schaldenbrand and Appleman in 1984 were the first to describe<unk> s as an independent entity of intra-abdominal tumors that were neither carcinomas nor exhibit histologic features of smooth muscle or nerve cells.<unk> s are thought to be derived from the interstitial cells of Cajal or undifferentiated precursor cells that finally develop into interstitial cells of Cajal. Genes involved in the pathogenesis of<unk> s include mutations in proto-oncogenes such as c-Kit gene and PDGFRA (platelet derived growth factor receptor-alpha) gene. The symptoms of<unk> s depends upon the tumor size and location. Majority of the<unk> s are asymptomatic. Patients with<unk>  who have symptoms (tumor size > 5cm) are generally non specific such as dysphagia, vague abdominal discomfort, jaundice and abdominal fullness. Common physical examination findings of<unk> s <unk>  include abdominal distension, palpable abdominal mass and in severe cases may present with signs of abdominal perforation and peritonitis. CT scan of the abdomen and pelvis is the imaging test of choice and an is important tool in the diagnosis of<unk>  <unk> . CT scan may be used to determine the size, location and staging of<unk> . A CT scan may also accurately de-mark surrounding structures, multiple tumors and metastases. The predominant therapy for<unk>  <unk>  is surgical resection. Medical therapy with tyrosine kinase inhibitors are indicated in patients with unresectable lesions, to decrease tumor size prior to surgery and for prevention of recurrent disease. Imatinib 400 mg to 800 mg PO q24h is the drug of choice for patients with aforementioned conditions. Patients resistant to imatinib are treated with sunitinib 50 mg PO q24h. Medical therapy such as fluid resuscitation, antibiotics cover, deep venous thrombosis prophylaxis should also be given to decrease perioperative morbidity associated with resection of<unk> .  Patients with<unk>  on medical therapy, tend to have a recurrent course and must be evaluated on a periodic basis with a CT scan or PET scan for early identification of recurrent disease.
Gastrointestinal stromal tumor
Krukenberg tumor
Signet ring cell carcinoma
Hilus cell tumor
Reticulum cell sarcoma
Esthesioneuroblastoma
Neurofibroma
Mycetoma