Thyroid gland
Benign neoplasms
Adenolipoma

Author: Jian-Hua Qiao, M.D., FCAP (see Authors page)
Editorial Board Member Review: Andrey Bychkov, M.D., Ph.D.

Revised: 12 September 2017, last major update August 2017

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Adenolipoma [title]

Cite this page: Qiao, J. H. Adenolipoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/thyroidadenolipoma.html. Accessed December 18th, 2017.
Definition / general
Essential features
  • Rare benign neoplasm
  • Usually well encapsulated; composed of variable combinations of follicular thyroid tissue (thyroid adenoma) and mature adipocytes
Terminology
  • 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
Epidemiology
Etiology
Clinical features
  • Most common clinical manifestation is a slowly enlarging neck mass
  • Large thyroid adenolipomas can cause obstructive symptoms, including airway obstruction
Diagnosis
  • 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

MRI

Prognostic factors
Case reports
Treatment
  • 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

Images hosted on other servers:

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:

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



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

Adipose metaplasia



Images hosted on other servers:

Adenolipoma


Adenolipoma

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