Thyroid & parathyroid

Papillary thyroid carcinoma

Main variants


Topic Completed: 2 March 2009

Minor changes: 6 August 2021

Copyright: 2003-2021,, Inc.

PubMed Search: cribriform-morular variant

Shahid Islam, M.D., Ph.D.
Page views in 2020: 3,421
Page views in 2021 to date: 3,326
Cite this page: Islam S. Cribriform-morular. website. Accessed December 6th, 2021.
Definition / general
  • Cribriform growth pattern and morular formations
  • Rare, 0.2% of papillary thyroid carcinoma (World J Surg 2004;28:886); associated with sporadic or germline mutations of APC gene (Am J Clin Pathol 2001;115:486)
  • Presence of tumor may suggest colon cancer screening for the patient due to association with familial adenomatosis polyposis
Clinical features
  • These lesions are usually associated with familial adenomatosis polyposis (FAP) but rarely may be sporadic (Int J Med Sci 2004;1:43)
Prognostic factors
Case reports
Microscopic (histologic) description
  • Tumors are encapsulated or circumscribed with cribriform, solid, papillary, tall columnar and morular patterns
  • Contains follicles without colloid, papillary formations of tall cells with abundant eosinophilic cytoplasm and pseudostratification, hyperchromatic nuclei with grooves and pseudoinclusions
  • Morular (squamoid) metaplasia with nuclear clearing resembling viral inclusions
  • Also spindle cells
  • Vascular and capsular invasion common
Microscopic (histologic) images

Case #470

Images hosted on other servers:

Complex branching
papillary structures
with nuclear features

Blending of various
histologic patterns

Whorls of cells
forming squamoid
morules or nests

Cribriform areas have
back to back follicles;
anastomosing cells;
no fibrovascular stroma

Cytology description
  • Papillary fragments and acini composed of columnar cells with fine to granular chromatin and nuclear grooves
  • Also occasional groups of epithelial cells forming morules (Acta Cytol 2005;49:75)
Cytology images

Case #470

May Grunwald Giemsa (MGG)

Pap stain

IHC Stains

Case #470


Positive stains
Electron microscopy description
Board review style question #1
What syndrome is associated with cribriform morular variant of thyroid carcinoma?

A. Carney complex
B. Familial adenomatous polyposis
C. Cowden syndrome
D. Gardner syndrome
Board review style answer #1
B. Familial adenomatous polyposis
Familial adenomatous polyposis is a rare condition transmitted in an autosomal dominant pattern related to germline mutation of the tumor suppressor gene APC, which strongly predisposes to colorectal cancer. Thyroid carcinoma rarely coexists with FAP (in just 0.3-1.2% of cases). When it does, it is almost exclusively CMV-PTC.

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