Fine‐needle aspiration cytology and immunocytochemistry in the diagnosis of 24 gastrointestinal stromal tumors: A quick, reliable diagnostic method

Abstract

The diagnosis of gastrointestinal stromal tumors (GISTs) is generally established on histopathologic examination of surgical specimens. Fine-needle aspiration (FNA), performed under the guidance of ultrasound or computed tomography, is being used with increasing frequency in an attempt to diagnose primary and/or metastatic GISTs before surgery. The present study was undertaken to characterize the cytological appearance of these tumors and to assess the role of cytology, together with immunocytochemistry (ICC), in the diagnosis of GISTs. Twenty-four GISTs diagnosed by FNA cytology at our institution have been reviewed. Immunocytochemical studies with c-kit and CD34 were performed in all cases on current or archival Papanicolaou-stained smears. All cases stained with c-kit, and 19 reacted with CD34. Cytomorphology and immunocytochemical characteristics are discussed. Our results confirm the utility of FNA together with ICC in the diagnosis of primary and/or metastatic GISTs.

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

“…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.…”

“…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.…”

“…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. 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.…”

Utility of DOG1 Immunomarker in Fine Needle Aspirates of Gastrointestinal Stromal Tumor

“…Seidal and Edvardsson [22] showed strong positivity for CD117 and CD34 on cytospin preparations of material aspirated from six GISTs. Lozano et al [9] performed ICC on PAP-stained smears from 24 GISTs with results comparable to those on cell blocks and surgical specimens. We have previously described good ICC results from our cytopathology laboratory in other tumors [23].…”

“…Immunohistochemistry for CD117 is a sensitive marker for confirmation of the diagnosis of GIST, and its utility has been demonstrated on cytological specimens, including cell blocks and FNA smears [6,7,8,9,10,11,12,13]. However, approximately 5-15% of GISTs are immunonegative for CD117, leading to false-negative results [1,3,5,14].…”