Thyroid gland
Papillary carcinoma
Diffuse follicular variant

Author: Shahidul Islam, M.D., Ph.D. (see Authors page)

Revised: 15 December 2016, last major update March 2009

Copyright: (c) 2003-2016,, Inc.

PubMed search: papillary carcinoma [title] thyroid "follicular"

Cite this page: Diffuse follicular variant. website. Accessed February 20th, 2017.
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
Micro Description
  • Diffuse or micronodular pattern of growth
  • More intratumoral fibrosis than classic variant
Micro Images
Images hosted on PathOut server:

Courtesy of Andrey Bychkov, M.D., Ph.D.

Infiltrative growth,
exclusive follicular
pattern, bright colloid

Images hosted on other servers:

2 cm tumor from 53 year old man with metastatic carcinoma in 13 / 19 cervical lymph nodes
(A, F) Marked intratumoral fibrosis;
(B) Tumor (T) and normal (N) thyroid, arrow marks advancing front of tumor;
(C) Dense colloid (arrow); (D) Clear nuclei with grooves (arrow)

Differential Diagnosis