Diagnosis of gastrointestinal stromal tumor by fine-needle aspiration biopsy: A cytological and immunocytochemical study

The diagnosis of gastrointestinal stromal tumors (GIST) is generally establ ished on histopathologic examination of surgical specimens. The present stu dy was undertaken to characterize the cytologic appearance of these hl,nors and to assess the utility of fine-needle aspirates, including immunocytoch emistry for the demonstration of c-kit (CD117) and CD34, in the preoperativ e diagnosis. The study comprised preoperative fine-needle aspirates in thre e cases and aspirates performed on fresh surgical specimens in eight cares. The routinely stained smears revealed a mesenchymal cell population, predo minated by spindle cells. In five of six cases a strong positivity for c-ki t was demonstrated and in three of five cases a strong CD34-expression was found in the tumor cells. These results show that fine-needle aspiration ap pears to be a useful method for the recognition and diagnosis of GISTs or I CC (interstitial cell of Cajal) tumors.