Classification System

Milan 1: Non-Diagnostic

  • Insufficient quantitative or qualitative cellular material to make a cytologic diagnosis
  • 10% maximum rate
  • Minimum of 60 lesional cells for adequacy
  • Milan 2: Non-Neoplastic

    Specimens lacking evidence of a neoplastic process:
  • Inflammatory, metaplastic, and reactive
  • Reactive lymph nodes (flow cytometry is needed)
  • Clinico-radiological correlation is essential to ensure that the specimen is representative of the lesion.
  • A subset will need surgical excision to exclude a poorly sampled neoplasm.
  • Milan 3: Atypia of Undetermined Significance (AUS)

  • Cannot entirely exclude a neoplasm.
  • Heterogeneous category
  • A majority will be reactive atypia or poorly sampled neoplasms.
  • Specimens are often compromised (eg, air-drying, blood clot).
  • Limited use (<10 % of all salivary gland FNAs).
  • Milan 4: Neoplasm

    i) Benign Neoplasm
  • Reserved for classic benign neoplasms
  • This category will include conventional cases of PA, WT, lipoma, schwannoma, others
  • ROM <5%
  • ii) Salivary Gland Neoplasm of Uncertain Malignant Potential
  • Diagnostic of a neoplasm; however, a diagnosis of a specific entity cannot be made.
  • A malignant neoplasm cannot be excluded.
  • Diagnostic of a neoplasm; however, a diagnosis of a specific entity cannot be made.
  • ROM is 35%
  • Many benign neoplasms and some low-grade carcinomas
  • Divided into several subgroups including:
  • Cellular Basaloid Neoplasm
  • Cellular Oncocytic / Oncocytoid Neoplasm
  • Cellular Neoplasm with Clear Cell Features
  • Milan 5: Suspicious for Malignancy

  • Aspirates which are highly suggestive of malignancy but not definitive.
  • Often high-grade carcinomas with limited sampling or other limitation
  • Milan 6: Malignant

  • Aspirates which are diagnostic of malignancy.
  • Sub-classify into specific types and grades of cancer
  • Grading is critical for clinical management
  • “Other” malignancies such as lymphomas, sarcomas, and metastases are also included in this category and should be specifically designated.