Endoscopic sonographically guided fine-needle aspiration yield in submucosal tumors of the gastrointestinal tract.

OBJECTIVE: To study the yield of endoscopic ultrasonographically guided fine-needle aspiration cytologic examination in the diagnosis of submucosal masses. METHODS: From 1999 to 2003, 10 patients underwent ultrasonographically guided fine-needle aspiration for the cytologic diagnosis of submucosal masses in our institution. The endoscopic ultrasonography records and the cytology database were consulted, and the reports were analyzed, as were slide material and the technical aspects related to these procedures. All procedures were performed under conscious sedation and cardiorespiratory monitoring on an outpatient basis. Ten patients (4 men and 6 women; mean age, 60.8 years) were studied. RESULTS: Eight lesions were located in the stomach, and 2 were located in the esophagus, with a mean diameter of 3.3 cm. An experienced cytopathologist was present on-site during all procedures for assessment of adequacy and preliminary cytologic examination. Cytologic diagnoses were obtained in 8 cases as follows: 6 gastrointestinal stromal tumors, 1 organizing submucosal hematoma, and 1 low-grade mucosa-associated lymphoid tissue-associated lymphoma. Two cases consisted of scant gastric epithelium only and were considered nondiagnostic. The cytologic diagnoses guided further clinical treatment. CONCLUSIONS: Ultrasonographically guided fine-needle aspiration with cytopathologic analysis has a high accuracy rate (80%) for diagnosing submucosal lesions. These findings potentially affect clinical decision making.

Recent advances in cell biology, diagnosis, and therapy of gastrointestinal stromal tumor (GIST).

The understanding of mesenchymal neoplasms of the gastrointestinal tract has evolved dramatically over the last two decades since gastrointestinal stromal tumor (GIST) was described as the most common stromal tumor arising anywhere from the esophagus to the ano-rectum. Although morphologically similar to other benign and malignant smooth muscle and neural stromal neoplasms, GIST constitutes a distinct group of rare gastrointestinal tract tumors that originate from the interstitial cells of Cajal, regulators of gut peristalsis that normally express CD117, which is the product of the c-KIT proto-oncogene that encodes a tyrosine kinase receptor that regulates cellular proliferation in GISTs. Virtually all GISTs occur from mutations of the c-KIT oncogene and exhibit consistent expression of c-KIT (CD117), which is considered the most specific criterion for a diagnosis of GIST. Gastrointestinal stromal tumors vary in their behavior and several features have to be considered to assess their malignant potential. The advent of sophisticated imaging techniques for the evaluation and sampling of stromal tumors of the gastrointestinal tract has resulted in improved detection of GISTs. The identification of a novel tumor-specific target in c-KIT resulted in the development of a tyrosine kinase-inhibitor (imatinib mesylate) that provides an encouraging option for treating GISTs. This article reviews recent advances in the understanding of the cell biology, diagnosis, and therapy of GISTS.