WHO classification of thymic tumors

Last revised by Francis Deng on 30 Apr 2022

Citation, DOI, disclosures and article data

Citation:

Gaillard F, Deng F, Knipe H, et al. WHO classification of thymic tumors. Reference article, Radiopaedia.org (Accessed on 18 Apr 2024) https://doi.org/10.53347/rID-9074

DOI:

https://doi.org/10.53347/rID-9074

Permalink:

https://radiopaedia.org/articles/9074

rID:

9074

Article created:

15 Mar 2010, Frank Gaillard ◉ ◈

Disclosures:

At the time the article was created Frank Gaillard had no recorded disclosures.

View Frank Gaillard's current disclosures

Last revised:

30 Apr 2022, Francis Deng ◉

Disclosures:

At the time the article was last revised Francis Deng had no financial relationships to ineligible companies to disclose.

View Francis Deng's current disclosures

Revisions:

4 times, by 4 contributors - see full revision history and disclosures

Systems:

Chest, Oncology

Sections:

Classifications

Tags:

thymus, cases

Synonyms:

World Health Organisation (WHO) classification of tumours of the thymus
WHO classification of tumours of the thymus
WHO classification of tumors of the thymus
WHO classification of thymic tumors

The World Health Organization (WHO) classification of tumors of the thymus is a component of the WHO classification of thoracic tumors, which was published in its 5^th edition in 2021 ¹. It is a pathological classification of thymic epithelial tumors, including thymomas, thymic carcinomas, and neuroendocrine tumors ².

Classification

thymoma
- type A thymoma
- type AB thymoma
- type B1 thymoma
- type B2 thymoma
- type B3 thymoma
- micronodular thymoma with lymphoid stroma
- metaplastic thymoma
- lipofibroadenoma
thymic carcinoma
- squamous cell carcinomas
  - squamous cell carcinoma, NOS
  - basaloid carcinoma
  - lymphoepithelial carcinoma (previously lymphoepithelial-like carcinoma)
- NUT carcinoma of the thorax
- salivary gland-like carcinomas
  - mucoepidermoid carcinoma
  - clear cell carcinoma
    - hyalinizing clear cell carcinoma
  - sarcomatoid carcinoma
    - carcinosarcoma
- adenocarcinomas
  - adenocarcinoma, NOS
  - low-grade papillary adenocarcinoma (previously papillary adenocarcinoma)
  - thymic carcinoma with adenoid cystic carcinoma-like features
  - enteric-type adenocarcinoma
- adenosquamous carcinoma
- undifferentiated carcinoma
- thymic carcinoma, NOS
  - hepatoid carcinoma
  - rhabdoid carcinoma
  - undifferentiated large cell carcinoma associated with Castleman disease-like reaction
  - sebaceous carcinoma
thymic neuroendocrine neoplasms
- carcinoid tumor/neuroendocrine tumor
  - NOS
  - typical, grade 1
  - atypical, grade 2
- small cell carcinoma
- large cell neuroendocrine carcinoma
- combined small cell carcinoma and large cell neuroendocrine carcinoma

Most of the above are considered malignant under the International Classification of Diseases for Oncology (behavior code 3) ². The exceptions are that micronodular thymoma with lymphoid stroma is considered unspecified, borderline, or uncertain (behavior code 1) and lipofibroadenoma is considered benign (behavior code 0).