Oil blotting paper for formalin fixation increases endoscopic ultrasound-guided tissue acquisition-collected sample volumes on glass slides.

OBJECTIVES: Endoscopic ultrasound-guided tissue acquisition (EUS-TA) is used for pathological diagnosis and obtaining samples for molecular testing, facilitating the initiation of targeted therapies in patients with pancreatic cancer. However, samples obtained via EUS-TA are often insufficient, requiring more efforts to improve sampling adequacy for molecular testing. Therefore, this study investigated the use of oil blotting paper for formalin fixation of samples obtained via EUS-TA. METHODS: This prospective study enrolled 42 patients who underwent EUS-TA for pancreatic cancer between September 2020 and February 2022 at the Osaka International Cancer Institute. After a portion of each sample obtained via EUS-TA was separated for routine histological evaluation, the residual samples were divided into filter paper and oil blotting paper groups for analysis. Accordingly, filter paper and oil blotting paper were used for the formalin fixation process. The total tissue, nuclear, and cytoplasm areas of each sample were quantitatively evaluated using virtual slides, and the specimen volume and histological diagnosis of each sample were evaluated by an expert pathologist. RESULTS: All cases were cytologically diagnosed as adenocarcinoma. The area ratios of the total tissue, nuclear, and cytoplasmic portions were significantly larger in the oil blotting paper group than in the filter paper group. The frequency of cases with large amount of tumor cells was significantly higher in the oil blotting paper group (33.3%) than in the filter paper group (11.9%) (p = 0.035). CONCLUSIONS: Oil blotting paper can increase the sample volume obtained via EUS-TA on glass slides and improve sampling adequacy for molecular testing.

Sensitivity of cytology in liver tumor biopsy and its significance in the prompt clinical diagnosis of non-hepatocellular carcinoma.

BACKGROUND: Cytology is a fast and simple modality for identifying malignancies and tumor histology. In this study, we analyzed the sensitivity of cytology for liver tumor biopsy and evaluated its potential for prompt clinical diagnosis. METHODS: This retrospective study included patients who had concurrently undergone conventional cytology, on-site cytology, and histopathology for ultrasound-guided liver tumor biopsies. In the case of malignant tumors, malignancy was first diagnosed, then preliminary clinical diagnosis was established using histology based on cytology and clinical information, followed by histopathological diagnosis. Sensitivity of malignancy detection was evaluated by comparison with histopathological diagnosis. RESULTS: Of the 191 tumors, 164 (85.9%) were malignant. The sensitivity of conventional cytology for malignancy detection was 97.6%. The sensitivity of non-hepatocellular carcinoma (non-HCC) (99.3%) detection was higher than that of the HCCs (87.5%; p = 0.001). The sensitivity of on-site cytology for malignancy detection was as high as that of conventional cytology. Similar to conventional cytology, the sensitivity of on-site cytology for non-HCC detection (99.3%) was higher than that for HCCs (79.2%; p < 0.001). In most cases of non-HCC tumors (126/140, 90.0%), accurate preliminary clinical diagnoses were obtained by combining on-site cytology with clinical information. CONCLUSION: Cytology of liver tumor biopsy has high sensitivity for malignancy, especially in non-HCC tumors. On-site cytology can contribute to the prompt clinical diagnosis of non-HCC tumors when combined with clinical information. This approach may be a reassuring modality for patients with severely advanced cancers requiring prompt clinical diagnosis and quick initiation of treatment owing to their deteriorating health.