The Todani classification for bile duct cysts: an overview

Area of Science:

• Gastroenterology
• Surgical Oncology
• Medical Imaging

Background:

• Bile duct cysts (BDCs) are rare congenital anomalies, historically more prevalent in children but increasingly diagnosed in adults.
• The modified Todani classification is the current standard for BDCs, based on anatomical features.
• Limitations of the Todani classification include its failure to account for variations in epidemiology, pathogenesis, malignant potential, and treatment strategies.

Purpose of the Study:

• To evaluate the clinical significance and viability of the modified Todani classification for bile duct cysts.
• To address the exclusion of rare variants, such as cystic duct cysts, from the original classification.
• To propose an improved classification system that incorporates all BDC variations for better clinical application.

Main Methods:

• Review of existing literature on bile duct cyst classification and clinical management.
• Analysis of the strengths and weaknesses of the modified Todani classification.
• Assessment of the epidemiological and clinical data for rare BDC variants.

Main Results:

• The Todani classification, despite its limitations, offers simplicity, reproducibility, and widespread agreement, facilitating comparative studies.
• Rare variants like cystic duct cysts were initially omitted and later categorized as type VI, highlighting classification challenges.
• The current classification does not adequately address diverse aspects such as pathogenesis, malignant transformation risk, and tailored therapeutic approaches.

Conclusions:

• The Todani classification remains clinically significant due to its simplicity and widespread acceptance, enabling comparative patient analyses.
• Cystic duct cysts should be integrated into the existing Todani classification, potentially as a subtype of type II, rather than a distinct type VI.
• Standardizing the classification of all bile duct cyst variations is crucial for enhancing awareness and management among gastroenterologists, radiologists, and surgeons.