Endoscopic ultrasound-guided fine-needle aspiration biopsy for the diagnosis of gastrointestinal stromal tumors in the stomach.
BACKGROUND
For the diagnosis of gastric submucosal tumors (SMTs), endoscopic ultrasound (EUS) alone does not reveal the complete pathology, such as the degree of malignancy, and EUS-guided fine-needle aspiration biopsy (EUS-FNAB) has been reported to be more useful. Recently, most cases initially diagnosed as leiomyosarcomas have received further study with immunohistochemical staining and have been given the new diagnosis of gastrointestinal stromal tumors (GISTs). The degree of malignancy of GISTs differs widely in clinical aspects. In this study, we examined whether EUS-FNAB was useful in diagnosing GISTs and differentiating their degrees of malignancy.


METHODS
From January 1997 to March 2002, 21 cases of gastric GISTs were diagnosed from the immunohistochemical staining of specimens resected at Aichi Cancer Center Hospital. Of these 21 patients, 14 (5 with high-grade malignancy and 9 with low-grade malignancy) underwent EUS-FNAB preoperatively, and were examined further: their EUS-FNAB specimens were submitted for additional immunohistochemical testing.


RESULTS
The EUS-FNAB specimens from all patients were positive for c-kit and CD34 immunohistochemical testing, coinciding with the staining results of the resected specimens. The MIB-1 labeling indices in specimens of high-grade malignancy were significantly higher than those of low-grade malignancy. If we assumed that a tumor with an MIB-1 labeling index of more than 5% was a high-grade malignancy, the diagnostic accuracy was 85.7%.


CONCLUSIONS
The EUS-FNAB procedure is a useful tool for diagnosing GISTs of the stomach with immunohistochemical staining. When used with MIB-1 staining, the procedure may indicate GIST prognosis and influence decisions regarding therapeutic strategies.
Okubo
Kenji
K
Department of Gastroenterology, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-ku, 464-8681 Nagoya, Japan.
Yamao
Kenji
K
Nakamura
Tsuneya
T
Tajika
Masahiro
M
Sawaki
Akira
A
Hara
Kazuo
K
Kawai
Hiroki
H
Yamamura
Yoshitaka
Y
Mochizuki
Yoshinari
Y
Koshikawa
Takashi
T
Inada
Ken-Ichi
K
D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000032:analysis; D044963:Biopsy, Fine-Needle; D019160:Endosonography; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy; D046152:Gastrointestinal Stromal Tumors / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007124:Immunoenzyme Techniques; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis; D013270:Stomach / Q000473:pathology; D013274:Stomach Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D015996:Survival Rate
D018952:Antigens, CD34; D019394:Ki-67 Antigen; D019009:Proto-Oncogene Proteins c-kit