12.1 List the main organs and tissue of the head and neck region and describe their relative anatomy. Describe the relative position to each other.
Salivary glands, thyroid, parathyroid, lymph nodes. Carotid body, nasal, paranasal, nasal pharyngeal, laryngeal tracheal. Describe their relative anatomy.
12.2 What do you understand the term 'head and neck' cytopathology?
All cytopathology of lesions or tumours of the head and neck, such as nasal, paranasal, nasal pharyngeal, laryngeal tracheal, oral cavity, salivary gland, thyroid, parathyroid and lymph nodes.
The close proximity of the organs means that it is sometimes impossible to be sure of the nature of the tissue aspirated. These days most of the FNAs carried out on the ultrasound guidance which should a latter cytologist to correlate the cytological findings with the stated tissue.
12.3 Describe the main histological features of the organs found in the head and neck region. How does knowledge of this help with the reporting of cytology?
Having a working knowledge of histopathology is important for cytologists who are involved in examining fine needle aspirates, as tissue architecture will be reflected to some extent in the aspirated material.
For example papillary carcinoma of thyroid is characterised by presence of neoplastic papillae on a central core of fibrovascular tissue lined by one or several layers of cells with crowded oval nuclei. In some FNA sample even at low power the cytologist can see the papillary structures which are characteristic of this lesion. On closer examination intranuclear inclusions can be seen both in histological and cytological preparations. Another example is follicular adenoma or carcinoma. This lesion is characterized by presence of closely packed follicles, trabeculae or solid sheets. In FNA although is not possible to differentiate between a follicular adenoma and a follicular carcinoma, it is often possible to predict the follicular nature of the lesion by the presence of numerous dissociated loosely cohesive microfollicles.
12.4 What is the role of cytology in the diagnosis and management of thyroid nodules?
The main indication for fine needle aspiration of the thyroid is assessment of a thyroid nodule. Although the thyroid nodule raises a suspicion of neoplasia, fewer than 5% are malignant. Given the high prevalence of nodules, and inconvenience of surgical excision cytology has a part to play in the pre-diagnosis and screening lesions and reduce the number of unnecessary surgical procedures while increasing the yield for cancer.
Correlating cytology, radiological and clinical impression allows correct selection patient surgical procedures.
12.5 What are the common salivary gland neoplastic lesions and how can they be told apart?
In assessing fine-needle aspiration cytology of the salivary gland various elements must be considered, including the architecture, shape of the cells assessment of the nuclei, stroma and background material/cells.
In answering this question discuss the common benign lesions which have characteristic cytological features. For example the two common salivary gland tumours; pleomorphic adenoma and Warthin’s both have numerous cytological characteristics which allows for the accurate diagnosis.
Although the morphology of the salivary gland is relatively simple, there are numerous malignant lesions which can arise and have significant overlap. For example, assessment of basal lesions can be challenging as there is significant overlap between benign and malignant basal lesions. For example pleomorphic adenoma, basal cell adenoma, basal cell adenocarcinoma, adenoid cystic carcinoma, and basal cell carcinoma in all appear similar and in these cases descriptive and cautious report is warranted.