Background/Aim: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is the primary method for tissue acquisition of intra-abdominal masses. However, the main limitation of cytology alone is the lack of tissue architecture and inadequate samples. This study aimed to evaluate the diagnostic performance of combined conventional cytology and cell block preparation obtained from EUS-FNA of intra-abdominal masses without Rapid On-site Evaluation (ROSE). Methods: Cytologic smears and cell block slides of 166 patients undergoing EUS-FNA during 2010–2015 were reviewed by an experienced cytopathologist blinded to clinical data. Results: 125 patients had neoplastic lesions. Pancreatic adenocarcinoma was the most common etiology (35.5%), followed by lymph node metastasis (27.7%). The mean mass size was 2.5±1.3 cm. The mean number of passes was 1.9±1.28. Tissue adequacy for conventional cytology and cell block preparation was 78.9% and 78.1%, respectively. Factors associated with tissue adequacy were assessed. For cytology, lesions of > 2.1 cm, masses in the pancreatic body or tail, malignancy, and pancreatic cancer were positively associated with adequate cellularity. For cell block preparation, lesions of > 3 cm and malignancy were associated with increased tissue adequacy. The conventional cytology alone had a sensitivity of 68.5%, a specificity of 95.7%, and an area under the receiver operating characteristics (AUROC) of 0.821. The cell block preparation alone had a sensitivity of 65.4%, a specificity of 96%, and an AUROC of 0.807. The combined conventional cytology and cell block preparation performed significantly better than either method alone (p<0.05), as demonstrated by an increased AUROC of 0.853. Furthermore, cell block detected malignancy in 9.3% of cases where the cytologic smears failed to identify malignant cells. Conclusions: The combined conventional cytology and cell block preparation increased the diagnostic accuracy of EUS-FNA compared to either method alone. This approach should be implemented in routine practice, especially where ROSE is unavailable.

Background: The impact of rapid on-site cytologic evaluation (ROSE) on endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is widely debated. This study aims to assess the diagnostic performance of EUS-FNB in the absence of ROSE in abdominal masses. Methods: Patients with abdominal masses undergoing EUS-FNB using 22-gauge Franseen needles and the slow-pull technique were prospectively enrolled in this study. Macroscopic on-site evaluation (MOSE) was performed without ROSE. Results: 100 patients were recruited between 2018 and 2020. Seventy-eight patients had neoplasms, and twenty-two patients had benign diseases. Common diagnoses included pancreatic cancer (n = 27), mesenchymal tumors (n = 17), and metastatic tumors (n = 14). The mean mass size was 3.9 ± 2.6 cm. The median pass number was three. Eighty-nine percent had adequate specimens for histologic evaluation. Malignancy increased the odds of obtaining adequate tissue (OR 5.53, 95% CI, 1.36–22.5). For pancreatic cancer, FNB had a sensitivity of 92.3%, a specificity of 100%, a positive predictive value (PPV) of 100%, a negative predictive value (NPV) of 97%, and an AUROC of 0.96. The sensitivity, specificity, PPV, NPV, and AUROC for mesenchymal cell tumors were 100%, 95.9%, 84.2%, 100%, and 0.98, respectively. For metastatic tumors, FNB was 100% sensitive and specific, with an AUROC of 1.00. There were no procedure-related complications. Conclusions: 22-gauge Franseen needles with the slow-pull technique and MOSE without ROSE provide excellent diagnostic performances for malignant lesions. Thus, MOSE should be implemented in real-world practice, and ROSE can be obviated when EUS-FNB is employed.

Aggressive systemic mastocytosis: unraveling the mystery behind chronic diarrhea