Cytologic diagnosis of gastrointestinal stromal tumors of the stomach by endoscopic ultrasound‐guided fine‐needle aspiration biopsy: Cytomorphologic and immunohistochemical study of 12 cases

Abstract

Gastrointestinal stromal tumor (GIST) is an uncommon tumor, which was usually diagnosed by endoscopic biopsy or surgical resection. This study evaluated the efficacy and accuracy of endoscopic ultrasound (EUS) -guided fine-needle aspiration (FNA) biopsy in the diagnosis of GIST and reported its cytomorphologic features. Twelve patients with gastric GIST were diagnosed through EUS-guided FNA. Immediate on-site evaluation and cytologic diagnoses were given in nine cases (75.0%) with an average of three passes. Cell blocks provided diagnostic material in three cases (25.0%). Spindle cells were present in the cytologic material in all cases. Two patients had subsequent surgical resections. Immunohistochemical (IHC) studies performed in cell blocks and two surgical specimens all supported the original diagnoses. In the two cases with surgical resections, IHC results in cell blocks were similar to that in the resected specimens. This study demonstrated that when combining smears and cell blocks, EUS-guided FNA is accurate and efficient in the diagnosis of GIST. IHC reactivity in cell blocks correlated with that of the main tumors.

Endoscopic Sonographically Guided Fine-Needle Aspiration Yield in Submucosal Tumors of the Gastrointestinal Tract

“…20 Several factors, such as patient age, tumor location and size, mitotic index, cytologic grade, DNA ploidy, and the presence of kit mutations, need to be taken into consideration to determine the malignant potentiality of a GIST. 20 Therefore, we agree with Gu and colleagues 19 that, because of the unpredictable behavior of GISTs, surgical resection and complete histologic analysis should be recommended for treatment of patients with GISTs.…”

“…The presence of an on-site cytopathologist is a routine practice in our unit, which may have helped increase our accuracy to 80% compared with the initial reports of around 60% in some series. Other authors have also stressed the importance of a close collaboration between the pathologist and the endosonographer to aspirate the minimal material suitable for a diagnosis without exposing the patient to additional unnecessary punctures 19 while maximizing the diagnostic yield.…”

“…Other authors also have showed that, by combining smears and cell blocks with immunocytochemical studies, the samples obtained from EUS-FNA are highly accurate and efficient for a conclusive diagnosis of GIST. [19][20][21] Gastrointestinal stromal tumors strongly express positivity for ckit, and this reaction is necessary to name a tumor a GIST. Up to 70% of GIST lesions can also express positivity to CD34, and between 20% and 30% react with smooth muscle actin.…”

“…20 Despite those characteristics, it remains difficult to differentiate a benign from a malignant GIST solely on the basis of FNA samples because some features of malignant GIST such as mitotic index (>5/50 high-power fields), tumor necrosis, and nuclear pleomorphism may not be fully and accurately assessed in cytologic materials. 19 The presence of kit mutations in GISTs is a predictive factor of malignant behavior, but its absence does not completely rule out malignancy. 20 Several factors, such as patient age, tumor location and size, mitotic index, cytologic grade, DNA ploidy, and the presence of kit mutations, need to be taken into consideration to determine the malignant potentiality of a GIST.…”

Contribuição dos aspectos endoscópicos e ecoendoscópicos para o diagnóstico diferencial das lesões subepiteliais gástricas

“…, [9][10][11][12][13][14][15][16] Lesões não neoplásicas como pâncreas ectópico também podem corresponder à LSE. Também denominado pâncreas aberrante ou heterotópico, é definido como tecido pancreático não tópico sem continuidade vascular ou anatômica com o pâncreas normal, ocorre em aproximadamente 1,1% dos exames de EDA e 0,6-13% das autópsias; em 90% dos pacientes é encontrado do estômago, duodeno ou jejuno proximal.…”