A leiomyosarcoma is a malignant tumor arising from smooth muscle. Most authors classify leiomyosarcomas as a type of gastrointestinal stromal tumor (GIST), along with GI leiomyomas, leiomyoblastomas and schwannomas. GISTs comprise about 80 percent of all mesenchymal tumors depending on the classification criteria used. They usually occur in the stomach and small intestine, and occasionally in the esophagus. The following steps will show how to diagnose a leiomyosarcoma.
Expect GISTs to have a wide range of symptoms. Many are asymptomatic and discovered only incidentally, but others may cause pain and bleeding, especially as they get larger.
Observe the vomiting of blood and bloody stools in the case of large GISTs. A palpable mass also may be present. A GIST also may become perforated in 20 percent of cases.
Perform a Computed Tomography (CT) scan with intravenous and oral contrast materials because it is ideal for defining the extent of the tumor. Smaller GISTs should appear as smooth well-defined masses. Larger GISTs may be necrotic with the expected irregular shape and variable thickness.
Run a Magnetic Resonance Imaging scan (MRI). GISTs are frequently isodense on T1-weighted images and hyperdense on T1-weighted images when compared to skeletal muscle.
Examine the lesion histologically for the most definitive diagnosis. A biopsy can be taken with fine needle aspiration and analyzed using immunochemical staining techniques. This is rarely done, however, because the risk of perforation of the peritoneum or seeding the tumor is usually considered greater than the need for a definitive diagnosis.