**3.8 Thyroid adenoma**

These are benign tumors, classified as either follicular (most common form) or papillary (rare) type. Adenomas may be hyper functioning when they are termed toxic adenoma. Follicular adenoma are histopathologically divided into Fetal (micro follicular), Colloid (macro follicular), Embryonal (atypical), Hurthle cell adenoma (oxyphil or oncocytic tumor) types. Among these with the exception of colloid type all other histopathological types have potential for micro invasion.

### **3.9 Thyroid malignancies**

Thyroid malignancies are classified as papillary carcinoma (most common type), follicular carcinoma, medullary thyroid carcinoma, anaplastic carcinoma, thyroid lymphoma (rare) clinical features are explained below.
