Thyroid & parathyroid
Thyroid - general
WHO classification
Author: Andrey Bychkov, M.D., Ph.D.
Last author update: 1 September 2017
Last staff update: 20 January 2021
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: WHO classification of thyroid cancer
Table of Contents
WHO (2017) - Thyroid gland | WHO (2017) - Parathyroid gland | Diagrams / tables | Major Updates | Additional referencesCite this page: Bychkov A. WHO classification. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/thyroidwho.html. Accessed April 19th, 2024.
WHO (2017) - Thyroid gland
- Tumours of the thyroid gland ICD 0 codes
- Follicular adenoma 8330/0
- Hyalinizing trabecular tumour 8336/1
- Other encapsulated follicular patterned thyroid tumours
- Follicular tumours of uncertain malignant potential 8335/1
- Well differentiated tumour of uncertain malignant potential8348/1
- Noninvasive follicular thyroid neoplasm with papillary-like nuclear features 8349/1
- Papillary thyroid carcinoma
- Papillary carcinoma8260/3
- Follicular variant of PTC8340/3
- Encapsulated variant of PTC8343/3
- Papillary microcarcinoma8341/3
- Columnar cell variant of PTC8344/3
- Oncocytic variant of PTC8342/3
- Follicular thyroid carcinoma (FTC), NOS8330/3
- FTC, minimally invasive8335/3
- FTC, encapsulated angioinvasive8339/3
- FTC, widely invasive8330/3
- Hürthle (oncocytic) cell tumours
- Hürthle cell adenoma8290/0
- Hürthle cell carcinoma8290/3
- Poorly differentiated thyroid carcinoma 8337/3
- Anaplastic thyroid carcinoma 8020/3
- Squamous cell carcinoma 8070/3
- Medullary thyroid carcinoma 8345/3
- Mixed medullary and follicular thyroid carcinoma 8346/3
- Mucoepidermoid carcinoma 8430/3
- Sclerosing mucoepidermoid carcinoma with eosinophilia 8430/3
- Mucinous carcinoma 8480/3
- Ectopic thymoma 8580/3
- Spindle epithelial tumour with thymus-like differentiation 8588/3
- Intrathyroid thymic carcinoma 8589/3
- Paraganglioma and mesenchymal / stromal tumours
- Paraganglioma 8693/3
- Peripheral nerve sheath tumours (PNSTs)
- Schwannoma9560/0
- Malignant PNST9540/3
- Benign vascular tumours
- Haemangioma9120/0
- Cavernous haemangioma9121/0
- Lymphangioma9170/0
- Angiosarcoma 9120/3
- Smooth muscle tumours
- Leiomyoma8890/0
- Leiomyosarcoma8890/3
- Solitary fibrous tumour 8815/1
- Hematolymphoid tumours
- Langerhans cell histiocytosis 9751/3
- Rosai-Dorfman disease
- Follicular dendritic cell sarcoma 9758/3
- Primary thyroid lymphoma
- Germ cell tumours
- Benign teratoma9080/0
- 9080/1 Immature teratoma9080/1
- 9080/3 Malignant teratoma9080/3
- Secondary tumours
- ICD 0 note: the first four digits indicate the specific histological term; the fifth digit after the slash (/) is the behavior code, including /0 for benign tumors, /1 for unspecified, borderline or uncertain behavior, /2 for carcinoma in situ and grade III intraepithelial neoplasia (not used for adrenal tumors), and /3 for malignant tumors
WHO (2017) - Parathyroid gland
- Tumours of the parathyroid glands ICD 0 codes
- Parathyroid carcinoma 8140/3
- Parathyroid adenoma 8140/0
- Secondary, mesenchymal and other tumours
- ICD 0 note: the first four digits indicate the specific histological term; the fifth digit after the slash (/) is the behavior code, including /0 for benign tumors, /1 for unspecified, borderline or uncertain behavior, /2 for carcinoma in situ and grade III intraepithelial neoplasia (not used for adrenal tumors), and /3 for malignant tumors
- References: Lloyd: WHO Classification of Tumours of Endocrine Organs (IARC WHO Classification of Tumours), Fourth Edition, 2017
Diagrams / tables
Contributed by Andrey Bychkov, M.D., Ph.D.
WHO classification: thyroid tumors
Major Updates
- A group of borderline thyroid tumors has been introduced for the first time:
- FT - UMP (follicular tumor of uncertain malignant potential)
- WDT - UMP (well differentiated tumor of uncertain malignant potential)
- NIFTP (noninvasive follicular thyroid neoplasm with papillary nuclear features)
- Papillary thyroid carcinoma (PTC) variants:
- Conventional / classic variant
- Papillary microcarcinoma
- Encapsulated PTC – applicable to fully encapsulated classic PTC
- Follicular variant – PTC with an exclusively or almost exclusively follicular pattern, and no developed papillae
- Diffuse sclerosing variant
- Tall cell variant
- Columnar cell variant
- Cribriform-morular variant
- Hobnail variant – new entity
- PTC with fibromatosis/fascitiis-like stroma
- Solid/trabecular variant
- Oncocytic variant
- Spindle cell variant
- Clear cell variant
- Warthin like variant
- Follicular thyroid carcinoma (FTC) groups:
- Minimally invasive FTC – capsular invasion only
- Angioinvasive FTC
- Widely invasive FTC – grossly invasive
- Hürthle cell (oncocytic) tumors as a separate entity:
- include Hürthle cell adenoma and Hürthle cell carcinoma
- previously classified as oncocytic variant of follicular adenoma and FTC
- term "Hürthle" is favored over "oncocytic"
- Poorly differentiated thyroid carcinoma:
- Turin criteria were adopted
- Anaplastic thyroid carcinoma:
- "anaplastic" is favored over "undifferentiated"
