A) Borderline Tumours
- Follicular tumour of uncertain malignant potential FT-UMP
- Well differentiated tumour of uncertain malignant potential WDT-UMP
- Non-invasive follicular thyroid neoplasm with papillary nuclear features NIFTP
Equivalent to CIS in other structures
B) Malignant Tumours
- Thyroid Cell Origin
- Papillary Thyroid Carcinoma & variants
- Follicular Thyroid Carcinoma
- Hurthle Cell Carcinoma
- Poorly differentiated thyroid carcinoma
- Anaplastic thyroid Carcinoma
- Neuroendocrine C - cell
- Medullary Carcinoma
- Thyroid Lymphoma
- Miscellaneous
- Metastatic
"Differentiated Thyroid Carcinoma" (DTC)
Most common ~95% of Thyroid Ca
from Thyroid Follicular Epithelial Cells
Are PTC, FTC and Hurthle Cell
MEN2 / Cowden syndrome / FAP Specific gene mutations including RET, TRK, RAS, BRAF, PPArG, TP53
- Radiation. Especially childhood
- Iodine rich areas => PTC
- Iodine poor areas => FTC & Anaplastic. Relationship is less well defined
- Thyroiditis = Hashimotos => Lymphoma
| Name | Demo | Histo | CF | Prognosis |
|---|---|---|---|---|
| Papillary Thyroid Carcinoma (PTC) |
70% of all x= 30-40y 3F:1M Risks: Radiation Iodine |
Low-grade tumour Psammoma Bodies => MicroCa Freq Multicentric => Worse prog but still low |
Spread: Regional LN Then often stops Rare => Mets: Lung>Bone, Liver, Brain Microcarcinoma <10mm, clinically silent, excellent prognosis. 37% of Finns at PM. |
Generally Excellent But behaviour varies with age In young <50yo then LN+ => No fx on RIP >5cm => No fx on RIP Lung mets => Mild fx on RIP But >50yo then they all have sig fx as well as histo For <2cm tumours then Age>45, LN+, Mets+, Extrathyroid extension => ^RIP. |
| Follicular Thyroid Carcinoma (FTC) | 20% of all x=50y 3F:1M Risks: Radiation Iodine deficiency |
Slow-growing. Looks like normal thyroid tissue esp on cyto though can have sheets of anaplastic cells as well Ca is rare Multicentric is rare Assessing malignancy is tricky and usually by vasc invasion +/- mets |
Spread: LN = Rare Mets => Bone, liver, lungs. 20% = Mets at presentation. Bones & Lungs 5% = LN+ at presentation Recurrence in 44% |
Degree of invasion Degree of Differentiation +/- Mets |
| Hurthle (Oncocytic) Cell Carcinoma | Follicular neoplasm with >75% oncocytic cells Called malignant if shows capsular or vascular invasion |
Similar to FTC but more aggressive with ^ mets but similar recurrence | Age Invasion (esp extrathyroid invasion) |
|
| Poorly Differentiated Carcinoma | Older than DTC | Limited follicular Differentiation | Behaviour between differentiated and anaplastic Ca. | Poor |
| Anaplastic (Undifferentiated) Carcinoma | 1-2% 50-60 Risks: Radiation esp if young |
Giant or Spindle cells | Aggressive invasive mass LN+ common at presentation Then into distant nodes |
V. Poor RIP <1yr |
| Medullary Carcinoma of Thyroid | 5-10% Familial = 40-50 Sporadic = any age AD mutant of RET oncogene MEN 2a or MEN 2b or 'Familial MTC' |
Parafollicular C-Cells Upper 1/3 of thyroid Variable appearances Ca2+/Bone/Necrosis/Haem/Cyst No follicles. Stromal Amyloid |
Can be quite indolent MTC => Calcitonin ^. ^CEA is seen mostly in aggressive disease Uncommonly can produce ACTH, Histamine and others. |
|
| Lymphoma | 2% of Thyroid Malignancy F > M 50+ |
Most para-follicular B-cell type Also MALT (~Hashimotos) Rare = HD or T-cell |
LN+ common GIT also affected |
Papillary VARIANTS: Conventional / Classic variant, Papillary microcarcinoma, Encapsulated PTC, Follicular variant(= Follicular with Pap elements. Sim prog + bhr to PTC), Tall Cell variant(= >40, Aggressive -> RIP), Diffuse Sclerosing Variant(= Kids, poor prog untreated but Normal with treatment), Oncocytic variant PTC(= 10%. 4M:F, Autoimmune thyroiditis - sim to PTC)
Follicular is SUBCLASSIFIED as: Minimal Invasion, Angioinvasive, Widely Invasive.
| Finding | Explanation | Notes |
|---|