International Cytology Guidelines

The following international standardised systems for cytopathology reporting have been endorsed by the RCPA Cytopathology Advisory Committee and the Cancer Services Advisory Committee.

These international standards are currently not the subject of any published or planned RCPA Structured Pathology Reporting of Cancer protocols.

Laboratories should reference the reporting system in their report.

1. Milan system for reporting salivary gland cytology


Development of the Milan System was initially proposed in 2015, with the support of the American Society of Cytopathology and the International Academy of Cytology. The system aims to enable triage of salivary gland lesions by identifying those requiring significant clinical management. A unique category in the system is “neoplasm” which is subdivided into benign and uncertain malignant potential groups. These categories address the limitations in cytological diagnosis of some salivary gland neoplasms which have overlapping morphological features. The aims are to optimise patient management. Aggressive surgery would be avoided in equivocal cases. Risk of malignancy ranges are provided for each category based on the currently available literature; these parameters may be modified as further evidence is available following implementation of the Milan System.



WC Faquin, ED Rossi, Z Baldoch, eds. The Milan System for Reporting Salivary Gland Cytopathology. Bazel, Switzerland: Springer International Publishing AG; 2018.

2. Paris system for reporting urine cytology


Accurate cytological assessment of urine and communication of results allow for optimal management pathways for patients. A perceived lack of clinical application of urine cytology reports led to the concept of an improved reporting system at the International Academy of Cytology Congress in Paris May 2013. An international working group followed, led by Drs Rosenthal and Wojcik.

The main goal of the Paris System is detection of the clinically important high-grade urothelial carcinoma. The shortcomings of cytological diagnosis of low-grade urothelial neoplasia are acknowledged in this system, with strict criteria required for diagnosis. Indiscriminate use of equivocal categories has also been an issue in urine cytology. Standardised morphological criteria are provided in the atypical and suspicious categories in this system.



DL Rosenthal, EM Wojcik, DFI Kurtycz, eds. The Paris System for Reporting Urinary Cytology. 1st ed. Cham, Switzerland: Springer International Publishing AG; 2016.

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