Thyroid Gland
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Thyroid Gland (ICD‐O‐3 C73.9)
The classification applies only to carcinomas. There should be microscopic confirmation of the disease and division of cases by histological type. The following are the procedures for assessing T, N, and M categories: T categories Physical examination, endoscopy, and imaging N categories Physical examination and imaging M categories Physical examination and imaging
Regional Lymph Nodes The regional lymph nodes are the cervical and upper/superior mediastinal nodes.
TNM Clinical Classification T – Primary Tumour* TX T0
T1
Primary tumour cannot be assessed No evidence of primary tumour
Tumour 2 cm or less in greatest dimension, limited to the thyroid T1a Tumour 1 cm or less in greatest dimension, limited to the thyroid T1b Tumour more than 1 cm but not more than 2 cm in greatest dimension, limited to the thyroid T2 Tumour more than 2 cm but not more than 4 cm in greatest dimension, limited to the thyroid T3 Tumour more than 4 cm in greatest dimension, limited to the thyroid or with gross extrathyroidal extension invading only strap muscles (sternohyoid, sternothyroid, or omohyoid muscles) T3a Tumour more than 4 cm in greatest dimension, limited to the thyroid T3b Tumour of any size with gross extrathyroidal extension invading strap muscles (sternohyoid, sternothyroid, or omohyoid muscles) T4a Tumour extends beyond the thyroid capsule and invades any of the following: subcutaneous soft tissues, larynx, trachea, oesophagus, recurrent laryngeal nerve
Head & Neck
Rules for Classification