Assessment of Risk of Malignancy Using the WHO Reporting System for Liver Cytology

Summary: Introduction: WHO's new liver cytology reporting system aims to standardize communication with clinicians globally to improve patient management. Our study reclassifies liver cytology reports based on the WHO classification and assesses the risk of malignancy (ROM) in each category. Materials and Methods: Liver cytology reports from 2019 to 2023 were retrieved to obtain demographic details, clinical data, cytology, and surgical follow-up (SFU). Cytology diagnoses were reclassified using the WHO classification. ROM was analyzed based on SFU. Results: Our study had 976 cases, with most patients (93%, n=908) aged 40-90 years (average age: 67 years, range 1-96 years). M:F ratio was 1:1. Majority of lesions (400/525, 76%) were less than 5 cm. Location of the lesion was available in 633 cases, with right lobe being the most common(61%; n=383), followed by left lobe (33%, n= 212). 6% of lesions (n=38) were segmental. 883 cases (90%) underwent rapid onsite evaluation. Distribution of cases according to the WHO reporting and ROM in SFU and total cohort for each category is shown in TABLE 1. Diagnosis in benign category is shown in FIGURE 1. Atypical diagnosis includes atypical hepatocytes (n=10), glandular atypia (n=8), dysplastic nodule (n=5) and atypical lymphocytes (n=2). Diagnosis within malignant category includes, metastasis (n=651, FIGURE 2), hepatocellular carcinoma (n=62), lymphomas (n=18), intrahepatic cholangiocarcinoma (n=12) and hepatoblastoma (n=6). Distribution of malignant cases in the SFU cohort is shown in TABLE 2. Conclusions: The ROM observed in our study aligned well with the ROM of WHO reporting system. Metastasis was the most frequent diagnosis in the malignant category, while abscess was the most common among benign cases.