AbstractBackgroundCytology 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.MethodsThis 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.ResultsOf 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.ConclusionCytology 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.