Jim Zhai, MD, Mayo Clinic, Jacksonville, FL
Yash J. Patil, MD, University of Cincinnati, Cincinnati, OH
Frozen section interpretation is a critical component of daily practice for most surgical pathologists. An over-call may lead to an unnecessary invasive procedure resulting in an irreversible consequence; while an under-call may delay the proper procedure hence potentially miss the window to cure the patient. Diseases of the head and neck region could be difficult to diagnose due to the complex anatomy and the wide histological spectrum. The origins of these diseases can be epithelial, mesenchymal, melanocytic, lymphoid, or sometimes a combination. Rendering an accurate intraoperative diagnosis is often challenging and stressful considering the time limitation, freezing artifacts, and the immediate resulting surgical impact.
This course will concentrate on common practical issues in frozen section diagnoses of head and neck specimens. An algorithmic approach to differential diagnoses and how to avoid traps caused by freezing artifacts will be highlighted. The course will utilize evidence-based case-study material and an interactive approach between an otolaryngologist and a pathologist. Twelve cases representing most frequently encountered practical scenarios will be presented using the same format. The surgeon will start with his perspectives including patient history, clinical impression, and intraoperative pictures to emphasize the key question that is going to help him determine the subsequent surgical treatment. The pathologist will continue the case with specimen handling and key gross diagnostic features, then illustrate the overlapping and distinct histologic features on frozen sections among diagnostic dilemmas. General surgical pathologist, pathologists with special interest in GU pathology, pathologists in training (residents and fellows) will benefit most from this course.
Upon completion of this educational activity, participants should be able to: 1) Effectively interact between a surgeon (otolaryngologist) and a pathologist for the optimal intraoperative management; 2) Understand the limitations of head and neck frozen section diagnosis, and when to defer; as well as instances where a frozen section is contraindicated (but requiring additional use of relevant ancillary studies including flow cytometry and molecular techniques); 3) Identify differential diagnoses of mucosal squamous cell lesions and evaluation of the resection margins; 4) Explain the separation of carcinoma from its mimickers such as pseudoepitheliomatous hyperplasia induced by granular cell tumor, fungal infections, reactive changes including atypical stromal cells, epithelioid endothelial cells, and necrotizing sialometaplasia secondary to previous surgical, chemo/radiation treatments; 5) Define the classification of salivary gland tumors, using an algorithmic approach to analyze major diagnostic features such as the low power growth pattern (infiltrating versus well circumscribed/encapsulated), the number of tumor cell types (epithelial only or both the epithelial and mesenchymal components), cytologic atypia, etc. Pleomorphic adenoma, oncocytoma, Warthin tumor, mucoepidermoid carcinoma, adenoid cystic carcinoma, polymorphous low-grade adenocarcinoma, salivary duct carcinoma, myoepithelial carcinoma, etc. will be discussed. FNA-induced reactive change will be illustrated to avoid a misdiagnosis as a malignancy; 6) Handle small blue cell tumors in the head and neck area; 7) Distinguish a benign primary cystic lesion from a metastatic well-differentiated squamous cell carcinoma in a neck lymph node; 8) Recognize head and neck presentations of intracranial lesions such as meningioma and ectopic CNS tissue; 9) Understand frozen section diagnostic implications, pitfalls, and pearls in thyroid nodules and parathyroid glands.