Thyroid gland
Papillary carcinoma
Diffuse follicular variant

Topic Completed: 1 March 2009

Revised: 26 April 2019

Copyright: 2003-2017,, Inc.

PubMed search: papillary carcinoma thyroid follicular

Shahid Islam, M.D., Ph.D.
Page views in 2018: 1,308
Page views in 2019 to date: 1,086
Cite this page: Islam S. Diffuse follicular variant. website. Accessed October 21st, 2019.
Definition / general
  • Tumor involvement of most of a lobe or both lobes by follicular variant of papillary carcinoma
  • Uncommon (1 - 2% of papillary thyroid carcinomas at most)
  • Younger patients than those with classic papillary carcinoma
  • Aggressive with more extrathyroidal extension, nodal metastases and vascular invasion than classic (encapsulated) follicular variant of papillary thyroid carcinoma (Virchows Arch 2002;440:418, Cancer 2006;107:1255)
  • Also called nonencapsulated / infiltrative
Microscopic (histologic) description
  • Diffuse or micronodular pattern of growth
  • More intratumoral fibrosis than classic variant
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Andrey Bychkov, M.D., Ph.D.:

Infiltrative growth,
exclusive follicular
pattern, bright colloid

Images hosted on other servers:

Tumor from 53 year old man
with metastatic carcinoma in
13 / 19 cervical lymph nodes (fig. 2)

Differential diagnosis
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