Thyroid gland
Benign neoplasms

Author: Jian-Hua Qiao, M.D., FCAP
Editorial Board Member Review: Andrey Bychkov, M.D., Ph.D.

Revised: 5 January 2018, last major update August 2017

Copyright: (c) 2002-2018,, Inc.

PubMed Search: Adenolipoma [title]

Cite this page: Qiao, J. H. Adenolipoma. website. Accessed March 21st, 2018.
Definition / general
Essential features
  • Rare benign neoplasm
  • Usually well encapsulated; composed of variable combinations of follicular thyroid tissue (thyroid adenoma) and mature adipocytes
  • Adenolipoma = lipoadenoma (in the 4th edition of WHO classification, Lloyd: WHO Classification of Tumours of Endocrine Organs, 4th Edition, 2017)
  • Also thyrolipoma, thyroid hamartoma
  • In clinical settings (e.g. in studies based on imaging), thyrolipoma is often synonymous with thyrolipomatosis; however the latter term only points to the presence of adipose tissue in thyroid, which morphologically can be a diffusely distributed fat or lipoadenoma or even ectopic thymus / parathyroid
Clinical features
  • Most common clinical manifestation is a slowly enlarging neck mass
  • Large thyroid adenolipomas can cause obstructive symptoms, including airway obstruction
  • Diagnosis of thyroid adenolipoma is only possible after surgical resection by microscopic examination
Radiology description
  • Imaging results (CT, ultrasound and MRI) of cold thyroid nodules are usually nonspecific with extensive differential diagnoses (Radiology 2002;225:746)
Radiology images

Images hosted on other servers:

Thyrolipoma on CT


Prognostic factors
Case reports
  • Surgical excision is curative
Gross description
  • Variable sized thyroid goitrous / adenomatous nodules which can be focally calcified
  • Soft and yellow pattern represents adipose tissue
Gross images

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Cut surface

Microscopic (histologic) description
  • Variable proportion of mature adipocytes and thyroid follicles, from 10% to 90% of the whole lesion
  • Groups of adipocytes in thyroid goitrous / adenomatous nodules
Microscopic (histologic) images

Images hosted on PathOut server:

Image contributed by Andrey Bychkov, M.D., Ph.D.

Thyroid lipoadenoma

Adipose metaplasia

Images contributed by Jian-Hua Qiao, M.D., FCAP

Low power view shows clusters of mature adipocytes in a goitrous / adenomatous thyroid nodule

Intermediate power shows numerous mature adipocytes present

High power shows mature adipose tissue

High power view shows mature adipocytes in benign thyroid glandular / follicular elements

Images hosted on other servers:



Cytology description
Differential diagnosis
Board review question #1
The following statements about adenolipoma of the thyroid gland are correct, EXCEPT:

  1. Clinical presentation of adenolipoma is usually a slow growing neck mass
  2. Imaging studies of cold thyroid nodule are usually nonspecific with extensive differential diagnosis
  3. Large adenolipoma can cause airway obstruction
  4. Recurrence of adenolipoma after surgical resection is common
Board review answer #1
D. "Recurrence of adenolipoma after surgical resection is common" is incorrect - surgical resection of thyroid adenolipoma is curative with no recurrence or malignant potential