Like other endocrine organs (eg. pituitary gland, parathyroid gland). thyroid diseases generally manifest clinically in TWO main ways.

1. Enlargement (non-neoplastic or neoplastic)

• Determined by history, clinical examination and imaging

2. Abnormal function (hyper- or hypothyroidism)

• Assessed by blood investigations of various hormone levels (free T3 Free T4, TSH)

Remember, these two can co-exist (eg Graves disease - think about what the clinical presentation is).

The aetiology of thyroid conditions is widely variable, but the few that are more common and important are as featured in your lecture notes: 

1. Congenital conditions (eg. hypoplasia, ectopic thyroid)
2. Hyperplasia (simple or nodular hyperplasia due to decreased iodine availability)
3. Immune related (autoimmune, or other mechanisms of thyroiditis)
4. Neoplasms 

In clinicopathologic correlation, we would ask some questions. Eg. What condition is more likely to cause diffuse enlargement? Which causes a solitary nodule?

This mindmap helps summarise the various conditions as the pathology relates to the clinical presentation.