Clinicopathological analysis of 58 cases of gastrointestinal stromal tumor / 肿瘤研究与临床

ABSTRACT

Objective To investigate the clinical presentation, morphological features, immunohistochemical staining of the gastrointestinal stromal tumor (GIST), and its histogenesis as well. Methods The morphologic characteristics of GISTs were studied in 58 cases using light microscopy. The expression of c-kit(CD117), CD34 and vimentin were detected in all of the cases with EnVision staining. Results Among 58 cases of GISTs, 41 were spindle cell type, 5 epithelioid cell type and 12 mixture type, equivalent to 86.6 %(58 of 67) of all of the mesenchymal tumors of gastrointestinal tract admitted in the same period. The epithelioid cell type tumors were mainly composed of the epitheloid cells, predominantly short spindle, oval or round in pattern, with an overall eosinophilic cytoplasm by hematoxylin-eosin stain. Focal cytoplasmic vacuolization was often seen. Sometimes signet-ring like cells and cells with a clear cytoplasm were seen in the epithelioid stromal tumor. The tumor cells arranged in interlacing fascicles forming whorls or sometimes cell clusters. All of the 58 stromal tumors were strongly positive for vimentin (100 %), 55 out of 58 tumors positive for CD117 (94.8 %) and 46 out of 58 positive for CD34(79.3 %). Some cases also expressed SMA, actin, S-100 and MBP. Conclusions GISTs were the most common mesenchymal tumor seen in the gastrointestinal tract. Under light microscope, the morphology of stromal tumors sometimes looks like a leiomyoma or Schwannoma. The application of immunohistochemical markers (particularly CD117 and CD34) is considered necessary for the differential diagnosis. GISTs may originate from the pluripotential precursor cells like the interstitial cells of Cajal.