Fine-needle aspiration diagnosis of GIST: a diagnostic dilemma

Endoscopic Ultrasound Advanced Techniques for Diagnosis of Gastrointestinal Stromal Tumours

Gastrointestinal Stromal Tumors (GISTs) are subepithelial lesions (SELs) that commonly develop in the gastrointestinal tract. GISTs, unlike other SELs, can exhibit malignant behavior, so differential diagnosis is critical to the decision-making process. Endoscopic ultrasound (EUS) is considered the most accurate imaging method for diagnosing and differentiating SELs in the gastrointestinal tract by assessing the lesions precisely and evaluating their malignant risk. Due to their overlapping imaging characteristics, endosonographers may have difficulty distinguishing GISTs from other SELs using conventional EUS alone, and the collection of tissue samples from these lesions may be technically challenging. Even though it appears to be less effective in the case of smaller lesions, histology is now the gold standard for achieving a final diagnosis and avoiding unnecessary and invasive treatment for benign SELs. The use of enhanced EUS modalities and elastography has improved the diagnostic ability of EUS. Furthermore, recent advancements in artificial intelligence systems that use EUS images have allowed them to distinguish GISTs from other SELs, thereby improving their diagnostic accuracy.

Cell-block procedure in endoscopic ultrasound-guided-fine-needle-aspiration of gastrointestinal solid neoplastic lesions

In the present review we have analyzed the clinical applications of endoscopic ultrasound-guided-fine-needle-aspiration (EUS-FNA) and the methodological aspects obtained by cell-block procedure (CBP) in the diagnostic approach to the gastrointestinal neoplastic pathology. CBP showed numerous advantages in comparison to the cytologic routine smears; in particular, better preservation of cell architecture, achievement of routine haematoxylin-eosin staining equivalent to histological slides and possibility to perform immunohistochemistry or molecular analyses represented the most evident reasons to choose this method. Moreover, by this approach, the differential diagnosis of solid gastrointestinal neoplasias may be more easily achieved and the background of contaminant non-neoplastic gastrointestinal avoided. Finally, biological samples collected by EUS-FNA CBP-assisted should be investigated in order to identify and quantify further potential molecular markers.

Clinical course of gastrointestinal stromal tumor diagnosed by endoscopic ultrasound-guided fine-needle aspiration

BACKGROUND AND AIM

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumor of the gastrointestinal tract. However, little is known about the clinical presentation of GIST, especially small lesions. The purpose of the present study was to clarify the efficacy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for the diagnosis of GIST and to determine its clinical course.

METHODS

Pathological and clinical records of GIST extracted from our institutional database between 1996 and 2012 were reviewed. All GIST cases were diagnosed pathologically by surgical specimen or EUS-FNA. To examine the efficacy of EUS-FNA for the diagnosis of GIST, the pathological findings of EUS-FNA were compared with the surgical findings from resected cases. Next, to clarify the clinical presentation of GIST, imaging findings and changes in tumor size over time were evaluated in follow up.

RESULTS

Of 84 cases of GIST, 67 were resected surgically after EUS-FNA; tumor size was <20 mm in 19 patients, and ≥20 mm in 48 patients. For the diagnosis of small GIST<20 mm, sensitivity and positive predictive value of EUS-FNA were 81.3% and 100%, respectively. A total of 27 patients with GIST was follow up for more than 1 year. Tumor size increased significantly during follow up. However, generalized linear analysis showed that there was no significant relationship between tumor size and follow up period.

CONCLUSIONS

The present results showed that even small GIST can be correctly identified by EUS-FNA. Moreover, size of small GIST increased significantly during follow up.

Intraparietal esophageal leiomyomas diagnosed by endoscopic ultrasound-guided fine-needle aspiration cytology: Cytological and immunocytochemical features in two cases

Endoscopic ultrasound-guided fine-needle aspiration cytology (EUS-FNAC) has proven to be of significant value as a diagnostic method for the evaluation of esophageal mesenchymal tumors, such as true leiomyomas. Utilizing the cell block procedure, the present study reports the diagnostic approach of EUS-FNAC in two patients affected by this lesion, describing the cytological and immunocytochemical findings. Spindle-shaped elements with elongated nuclei were appreciable; moreover, the cytoplasmatic immunohistochemical positivity for smooth muscle actin and desmin strongly supported the diagnosis of leiomyoma when also taking into account the constant negativity for CD34, CD117 and S100. The differential diagnosis between spindle cell mesenchymal tumors and leiomyomas, and the clinico-therapeutic management of the latter are also discussed in the study.

Gastrointestinal stromal tumours of the stomach: Cytological and immunocytochemical diagnostic features of two cases diagnosed by endoscopic ultrasound-guided fine needle aspiration

The present study reports the diagnostic utility of endoscopic ultrasound-guided fine needle aspiration (EUS-FNAC) in two patients affected by gastrointestinal stromal tumours (GISTs) of the stomach. Clinically, the patients demonstrated skin pallor, melena, gastric discomfort and pain that had lasted three days or weeks. The cytological findings are discussed; these were strongly supported by immunocytochemical procedures that were performed on cell blocks and further confirmed following post-surgical histopathological examination. The crucial aim of GIST management is to determine a correct diagnosis in early-phase disease in order to realize an adequate curative surgical resection before the tumour becomes unresectable or metastatic. Moreover, a correct pre-surgical differential diagnosis of GISTs from other mesenchymal neoplasms may be easily made by EUS-FNAC, supported by cytological and immunocytochemical features.