The Contributory Role of Cell Blocks in Salivary Gland Neoplasms Fine Needle Aspirations Classified by the Milan System for Reporting Salivary Gland Cytology.

(1) Background: The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) was introduced in 2018, bringing an organ-specific classification system for salivary gland cytopathology. The aim of present study is to evaluate the MSRSGC prospectively, based on a two-year experience in the tertiary care center pathology department, and evaluate the role of routine cell block (CB) preparation in salivary gland cytopathological diagnostics. (2) Methods: In our institution, the Department of Pathology, Fimlab Laboratories, Tampere, Finland, the MSRSGC has been implemented in salivary gland cytopathology since January 2018 and, over a two-year period (January 2018-December 2019), there were 365 fine-needle aspirations, of which 164 had a surgical follow-up. The CB methods used were Plasma-thrombin, the collection of visible fragments, and the Shandon and in-house methods. (3) Results: The MSRSGC diagnostic figures were as follows: accuracy 87.5%, sensitivity 45.8% and specificity 98.9%. For diagnostic categories of MSRSGC (non-neoplastic, benign neoplasm and malignant neoplasm) (n = 63) diagnostic accuracy was 98.4%, and for undetermined categories (atypia of undetermined significance, salivary gland neoplasm of uncertain malignant potential and suspicious for malignancy) (n = 49) diagnostic accuracy was 73.5%. Non-contributory cell blocks resulted more often in a false negative diagnosis (25%, 3/12) than a true negative diagnosis (10%, 7/73, p < 0.001), and is, most likely, an insufficient cytological diagnosis (86%, 18/21, p < 0.001). (4) Conclusion: The application of MSRSGC and CBs are beneficial in salivary gland cytological diagnosis, increasing diagnostic accuracy and, thus, patients' management and treatment.

The Role of Cell Blocks and Immunohistochemistry in Thyroid Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance Bethesda Category.

INTRODUCTION: Thyroid cytology is a widely accepted tool in the clinical triaging of nodular lesions. Cell blocks (CBs) can help in the diagnosis of atypical lesions, namely, thyroid Bethesda category of Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS). METHODS: In a series of 224 AUS/FLUS thyroid samples with CB, we studied CB cellularity and feasibility of 3 immunohistochemical markers (cytokeratin 19 [CK19], HBME-1, and galectin-3) apart and in combination. RESULTS: The CBs were non-diagnostic in 34 cases. Twenty-four CBs contained <10 cells, 45 CBs 10-50 cells, and 121 CBs >50 cells. Notably, more cellularity was found in CBs performed by plasma-thrombin and in-house techniques (p < 0.001). The diagnostic accuracy to detect malignancy was 65.1% for CK19, 72.1% for HBME-1, and 70.3% for galectin-3. CONCLUSION: In conclusion, CB cellularity is essential for successful immunohistochemistry application and further diagnostic workup of AUS/FLUS cases.

New Cell Block Method to Enhance the Cellular Yield in Mucous and/or Bloody Samples.

OBJECTIVE: Cell blocks (CBs) are used to complement cytological diagnosis and for ancillary testing. Dissatisfaction with the cellular yield of the CB is widely recognized. Various techniques have been developed to increase the diagnostic utility of CBs. STUDY DESIGN: We invented a new CB technique to increase cellular yield and diagnostic accuracy suitable especially for mucous and/or bloody cytological samples. RESULTS: The new CB technique is described in detail with illustrations and cases, where it increased the cellular yield and diagnostic accuracy. CBs prepared by this method are suitable also for ancillary techniques, namely immunocytochemistry. CONCLUSIONS: The newly described method showed a better cellular yield in mucous and/or bloody cytological specimens.