Enterprise Interest None
Risk stratification of salivary gland lesions on cytology based on the proposed Milan System for reporting salivary gland cytopathology: A pilot study Kartik Viswanathan, M.D., Ph.D New York Presbyterian - Weill Cornell Medicine PGY-2 September 6 th, 2017
Salivary gland cytology is challenging Diverse diagnoses - non-neoplastic and neoplastic Cytomorphologic overlap among lesions Heterogeneous lesions
Diagnosis relies on imaging and fine-needle aspiration (FNA) ULTRASOUND: High sensitivity, low cost MRI: - Helps visualize tumor interface and perineural invasion (contrast enhanced) - Surgical planning in larger tumors (>4 cm) FNAC: Highly sensitive and specific with accuracy of ~ 87% to 96%.
Rationale and Indications for FNA Initial step in diagnosing an unexplained salivary gland mass Safe, cost-effective and accurate Guides clinical management: Non-neoplastic vs. Neoplastic Benign or low grade malignancy vs. high-grade malignancy Sample for molecular testing
Why do we need a categorization system for salivary gland lesions? Reporting is not standardized different diagnostic categories descriptive reports surgical pathology terminology Can cause confusion and make communication challenging between clinicians and patients.
The proposed Milan system Image courtesy of William Faquin
Category 1: Non-diagnostic Benign salivary gland Insufficient material Benign salivary gland elements only Non-mucinous cysts
Category 2: Non-neoplastic Inflammatory, metaplastic or reactive process Reactive lymph nodes Radiologic and clinical correlation to ensure that lesion is adequately sampled Sialadenitis
Category 3: Atypical Cannot exclude neoplasm Majority is reactive atypia or poorly sampled neoplasm Should be used rarely (<10% of FNAs) Rare atypical cells
Category 4a: Neoplastic - Benign Clear cut benign neoplasms - e.g. Pleomorphic adenoma, Warthin tumor Pleomorphic Adenoma
Category 4b: Neoplastic Uncertain Diagnostic of neoplasm malignant potential However, precise entity not identifiable or malignancy cannot be excluded Salivary gland neoplasm
Category 5: Suspicious for Malignancy All the features for a malignancy are not met or limited sample precludes certainty Suspicious for malignancy
Category 6: Malignant Aspirates diagnostic of malignancy Other malignancies such as lymphomas, sarcomas or metastases are also included Adenoid cystic carcinoma
Benefits of the proposed Milan system Easier to standardize reporting and research. Improves communication between pathologists and clinicians. Less confusion for patients and provides clear communication of risk of malignancy.
Our institutional experience with the proposed Milan system Retrospective search of our institutional pathology database for all cases of salivary gland lesions from 2012-2016 628 unique cytology cases were identified 367 cases have either surgical pathology or clinical follow-up
Our institutional experience with the proposed Milan system Assigned all cases to each Milan category based on the cytologic diagnosis Cases with surgical or clinical follow-up were used for risk of malignancy calculation Risk of Malignancy (ROM) = number of malignant cases / number of FNAs with follow-up
Our institutional experience with the proposed Milan system
Limitations of the study Cannot necessarily be generalized across other institutions Small number of cases Interobserver variability can cause misclassification of entities
Next steps After the Milan system is published, implement the risk of malignancy in our institution Survey clinicians to determine usefulness in practice Expand the data set to increase the precision of the risk of malignancy Understand the factors that affected the decision to over-call or under-call certain diagnoses.
Acknowledgements Mentors - Dr. Rema A. Rao - Dr. Grace Yang - Dr. Momin T. Siddiqui (Director) Fellows/Staff - Dr. Simon J. Sung - The Papanicolaou Laboratory at Weill Cornell
References 1. The Milan system for Reporting Salivary Gland cytopathology: Analysis and suggestions of initial survey. Rossi ED, Faquin WC, Baloch Z et al. Cancer Cytopathology. 2017 2. A pattern-based risk-stratification scheme for salivary gland cytology: A multi-institutional, interobserver variability study to determine applicability. Griffith CC et al. Cancer Cytopathology. 2017 3. Three-year cytohistological correlation of salivary gland FNA cytology at a tertiary center with the application of the Milan system for risk stratification. Rohilla M et al. Cancer Cytopathology. 2017 4. Reporting of fine needle aspiration (FNA) specimens of salivary gland lesions: A comprehensive review. Wei S, Layfield LJ et al. Diagnostic Cytopathology. 2017 5. The impact of FNAC in the management of salivary gland lesions: Institutional experiences leading to a risk-based classification scheme. Rossi ED, Wong LQ et al. Cancer Cytopathology. 2017. 6. Is it time to develop a tiered classification scheme for salivary gland fine-needle aspiration specimens? Baloch ZW, Faquin WC, Layfield LJ. Diagnostic Cytopathology. 2017 7. Relative accuracy of fine-needle aspiration and frozen section in the diagnosis of lesions of the parotid gland. Seethala RR, LiVolsi VA, Baloch ZW. Head Neck. 2005