Muscle Differentiation and Clinicopathologic Features of Gastrointestinal Stromal Tumors

Mutations of c-kit JM domain are found in a minority of human gastrointestinal stromal tumors

“…Our survey of 46 GISTs provides no support for this prediction. Our sample of tumors represented the vast majority of all such neoplasms collected at our institution over a de®ned time period (Franquemont and Frierson, 1992), and our high success rate in obtaining PCR products from this population makes a selection bias highly unlikely. In addition, our use of microdissection to enrich for tumor cells and direct cycle sequencing of PCR products makes false negative results unlikely.…”

“…In addition, our use of microdissection to enrich for tumor cells and direct cycle sequencing of PCR products makes false negative results unlikely. Although the categorization of GISTs remains somewhat controversial (Franquemont and Frierson, 1992;Hjermstad et al, 1987;Miettinen et al, 1995;Saul et al, 1987), even when using conservative criteria and limiting the diagnosis of GIST to those neoplasms negative for diuse desmin expression and positive for KIT, only nine of 43 such tumors (21%) had c-kit JM domain mutations. Although the majority of mutations were found in tumors with malignant clinical behavior, our sample size was too small to make this ®nding statistically signi®cant.…”

Gastrointestinal Stromal Tumours

“…To differentiate between clinically benign and malignant tumors originating from various sites, several large clinicopathologic studies of GISTs have accepted the contention that tumor size more than 5 em will have unfavourable prognosis [7,[10][11][12]. The size of the tumor has also been correlated with the histopathological findings in deciding the nature and their metastatic potential [8,9,13].…”

“…The pain abdomen and bleeding remain the commonest clinical presentation [3][4][5]7,12]. Franquement [12], considered GISTs of small bowel as malignant, or at least of indeterminate malignant potential, if the tumor measured over 5 em in size, revealed fresh tumor necrosis or extensive haemorrhage related to surgery. Simultaneously it should reveal extreme celluarity, marked atypia and high mitotic figures on microscopy.…”

“…The line of cell differentiation could only be finalised in these two cases on the basis of IHC. The common immunohistochemical markers used by various workers were vimentin, desmin, alpha smooth muscle actin and muscle specific actin markers (HHF-35) toward myogenic cells, and S-100 and NSE for neural elements [4,5,7,11,12,18]. Pike et al [20] studied GISTs by using various antibodies depending upon the location of tumors in GIT.…”