Immunohistochemistry (IHC) is widely and integrally employed in surgical pathology, and has become critical in many diagnostic settings. The first part of this short course updates pathologists on many of the problems relating to preanalytical, analytical, and postanalytical (interpretive) factors that can potentially lead to incorrect interpretations and diagnoses. These factors include incorporating the correct antibodies into the diagnostic panel, optimal fixation and epitope retrieval techniques, misinterpretation of immunostained slides and misinterpretation of the significance of selected immunostaining results. The second part of the course is a series of case studies highlighting the impact of IHC on tumor diagnosis, using the examples of: (a) carcinomas of unknown primary; (b) small, blue round cell tumor; (c) spindle cell tumor; (d) large cell undifferentiated malignant neoplasm. Discussion will be focused on selection of optimal antibody panels to maximize sensitivity and specificity, with each case introducing new markers that can be incorporated in these clinicopathologic setting, including: napsin A (a marker of lung cancer); INI1 (a marker of epithelioid sarcoma and rhabdoid tumors); arginase 1 (hepatocellular carcinoma); SALL4 (a marker of germ cell tumors); and TLE1 (marker of synovial sarcoma).

This course will benefit pathologists at all levels of training. Registrants will receive a syllabus at the course and have access to after meeting materials on the USCAP website.