Thyroid gland
Papillary carcinoma
Encapsulated follicular variant

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

Revised: 23 February 2017, last major update March 2009

Copyright: (c) 2003-2017,, Inc.

PubMed Search: papillary carcinoma thyroid encapsulated

Cite this page: Encapsulated follicular variant. website. Accessed July 17th, 2018.
Definition / general
  • Encapsulated follicular neoplasm with features of encapsulated and follicular variant of papillary carcinoma
  • Commonly sent for consultation
  • Recommended to use strict criteria for diagnosis, and to classify questionable cases as well differentiated thyroid neoplasm of uncertain malignant potential (Am J Clin Pathol 2002;117:16)
Prognostic factors
  • Excellent prognosis, better than nonencapsulated follicular variant (Cancer 2006;107:1255)
  • May have late bone metastases with follicular pattern but without papillary nuclear features (Mod Pathol 2000;13:861)
Microscopic (histologic) description
  • Capsular and vascular invasion may be present; if no capsular or vascular invasion present, should have widespread nuclear features of papillary carcinoma PLUS some additional features of papillary carcinoma (papillae, fibrous bands, dense eosinophilic colloid), otherwise diagnose as follicular adenoma or well differentiated thyroid neoplasm of uncertain malignant potential
Microscopic (histologic) images

Images hosted on PathOut server:

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

Enlarged vesicular nuclei with irregular membranes

Evident major and minor diagnostic features

"Minor diagnostic
features" include
dark colloid, frequent
scalloping, clefting

Free floating of small tumor fragment in vascular lumen

Small piece of tumor floats in vascular lumen

Images hosted on other servers:

Encapsulated follicular
lesion with nuclear
features of papillary
carcinoma #1 (inset)

#2 with capsular invasion

3 cm tumor in 51 year old man (fig. 1)

Various images

Metastases to bone

Virtual slides

Images hosted on other servers:

67 year old woman

Cytology description
  • Ultrafast Papanicolaou stained smears makes clear nuclei more conspicuous (Cancer 2006;108:174)
Cytology images

Images hosted on other servers:

Ultrafast Pap stain (fig. 2)

Diff-Quik versus
Ultrafast Pap staining of
follicular adenoma and
follicular variant (fig. 3)