Ancillary Tests in Cytopathology PDF

Ancillary Tests in Cytopathology EN HANCING DIAGNOSTIC ACCURACY IN MOD ERN CYTOLOGY DR. SHADIA AL BAHLAN I Introduction Definition: supplementing Not important you with provide Ancillary tests are supplementary dia...

Ancillary Tests in Cytopathology EN HANCING DIAGNOSTIC ACCURACY IN MOD ERN CYTOLOGY DR. SHADIA AL BAHLAN I Introduction Definition: supplementing Not important you with provide Ancillary tests are supplementary diagnostic techniques that enhance the accuracy of cytological evaluations. Light microscopy alone may not always yield sufficient information to render a specific diagnosis. Significance: - Resolving indeterminate diagnoses. - Providing additional prognostic and therapeutic information. Immunocytochemistry (ICC) Purpose: - Identifying cell origin using specific markers. - Differentiating benign from malignant processes. Common Markers: - CK7 and CK20 (epithelial tumors), TTF-1 (lung adenocarcinoma), p63 (squamous differentiation). Applications: - Useful in lung, breast, and head-and-neck malignancies. Molecular Techniques 1. Polymerase Chain Reaction (PCR): Detects specific mutations (e.g., EGFR in lung adenocarcinoma). 2. In-Situ Hybridization (ISH): Identifies chromosomal abnormalities (e.g., HER2 in breast cancer). 3. Next-Generation Sequencing (NGS): Comprehensive genomic profiling. Cytogenetics in Cytology Techniques: - Karyotyping and Fluorescence In-Situ Hybridization (FISH). Applications: - Urothelial carcinoma: UroVysion for chromosomal abnormalities. - Ewing sarcoma: a type of tumor that forms from a certain kind of cell in bone or soft tissue such as EWSR1 rearrangements. Flow Cytometry Purpose: - Analyzes DNA content and cell surface markers. Applications: - Hematologic malignancies such as lymphomas and leukemias. Example: - CD5/CD19 co-expression in chronic lymphocytic leukemia (CLL). Digital Image Analysis Advantages: - Quantitative analysis of nuclear features. - Detects subtle abnormalities in cell architecture. Applications: - Enhances early detection of malignancies. Biomarkers and Tumor Markers Examples: - Telomerase activity for cancer detection. - NMP22 for urothelial carcinoma. - NMP22 is an antibody-based test used to detect a nuclear matrix protein involved in maintenance of nuclear architecture, DNA transcription, and RNA synthesis. Utility: - Predicting tumor behavior. - Monitoring treatment response. Applications in Lung Cytology Markers for Diagnosis: Thyroidtranscriptionfactor - TTF-1 is thyroid transcription factor expression which is a diagnostic marker and a good prognostic indicator for lung adenocarcinoma. Molecular Tests: - EGFR mutations for targeted therapies. - EGFR is estimated glomerular filtration rate which is a measure of how well the kidneys are working. Gynecologic Cytopathology HPV Testing: - High-risk HPV typing in cervical cancer screening. Role in the Bethesda System: - Identifies precancerous lesions. Liquid-Based Cytology (LBC) Advantages: - Higher sensitivity for abnormalities. - Compatibility with ancillary studies (HPV, FISH). Examples: - ThinPrep®. - SurePath®. Soft Tissue Lesions Diagnostic Challenges: - Morphological overlap in soft tissue tumors. Ancillary Techniques: - FISH for sarcoma classification. Lymphoma Workup Flow Cytometry: - Identifies cell surface markers for lineage determination. Cytogenetics: - Detects chromosomal translocations. Pitfalls and Challenges Challenges: - False positives/negatives. - Interpretation variability. Solutions: - Standardized protocols. - Continuous training.  Ancillary Test Limitations Used in conjunction with initial morphologic evaluation along with clinical information. False positive and false negative results can occur. ICC tests may cross-react with antigens that are not intended to be reactive, or may have high background staining, which renders the test less interpretable. Positive and negative controls should be performed with each sample. An antibody specific and method specific control tissue, cell block or cytology preparation simultaneously stained with the unknown or target specimen is required.  Ancillary Test Limitations Suboptimal specimen preservation and areas of necrosis can contribute to problems in diagnosis. Flow cytometry requires a sufficient number of viable cells and sometimes only limited panels are possible. DNA quantization by image analysis is time consuming and requires a skilled morphologist. PCR is very sensitive; however, there is a high risk of contamination. Although FISH is becoming more widely available, it is still expensive and time consuming Technological Advances Emerging Tools: - Liquid biopsies for circulating tumor DNA. - Artificial intelligence (AI) in cytopathology. justknowdefinitionnditsexampled