Thyroid Gland Well-Differentiated Tumor of Uncertain Malignant Potential

**Semantic type:** Neoplastic Process

**Definition:** An encapsulated or well-circumscribed thyroid gland tumor composed of well-differentiated follicular cells with well-developed or partially developed nuclear features of papillary thyroid carcinoma and with questionable capsular or vascular invasion. This is a tumor indeterminate between follicular adenoma and follicular carcinoma. Tumors in which vascular invasion has been excluded by all means are called non-invasive follicular thyroid neoplasms with papillary-like nuclear features. (WHO)

**Synonyms:** - Atypical Follicular Adenoma - Atypical follicular adenoma - Thyroid Gland Atypical Follicular Adenoma - Thyroid Gland Well-Differentiated Neoplasm of Uncertain Malignant Potential - WDT-UMP