Classifying Liver Cytology Using the WHO Reporting System: Institutional Experience and Malignancy Risk Assessment

Area of Science:

• Hepatology
• Cytopathology
• Oncology

Background:

• Standardized reporting in liver cytopathology is crucial for accurate patient management.
• The World Health Organization (WHO) Reporting System for Liver Cytopathology provides a framework for consistent communication.
• Assessing the risk of malignancy (ROM) within cytopathology categories is essential for clinical decision-making.

Purpose of the Study:

• To reclassify liver cytology reports according to the WHO classification system.
• To determine the risk of malignancy (ROM) associated with each category of the WHO liver cytopathology classification.
• To evaluate the utility of repeat fine-needle aspiration (FNA) in specific diagnostic categories.

Main Methods:

• Retrospective review of 976 liver cytology reports from 2019-2023.
• Reclassification of cytology diagnoses based on the WHO classification system.
• Analysis of surgical follow-up (SFU) data to determine the risk of malignancy (ROM).

Main Results:

• The WHO classification yielded categories including non-diagnostic (n=79), benign (n=117), atypical (n=25), suspicious for malignancy (n=6), and malignant (n=749).
• The risk of malignancy (ROM) was 17% for non-diagnostic, 23% for benign, and 100% for atypical, suspicious, and malignant categories based on SFU.
• Repeat FNA showed high malignant upgrade rates: 80% in non-diagnostic and 75% in atypical categories.

Conclusions:

• This study provides ROM values for the WHO Reporting System for Liver Cytopathology categories.
• Repeat sampling is recommended for non-diagnostic and atypical liver cytology findings due to significant malignant upgrade rates.
• The WHO classification system aids in stratifying malignancy risk and guiding clinical management of liver lesions.