Thyroid gland
Hyperplasia / goiter
Amyloid goiter

Author: Swati Satturwar M.D. and F. Zahra Aly, M.D., Ph.D, FRCPath (see Authors page)

Revised: 20 June 2017, last major update June 2017

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

PubMed Search: Amyloid goiter [title] thyroid
Cite this page: Amyloid goiter. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/thyroidamyloidgoiter.html. Accessed October 20th, 2017.
Definition / general
Terminology
  • Also known as amyloid tumor of thyroid
Epidemiology
  • Median age 54 years, range 23 - 75 years
  • In adolescence associated with juvenile arthritis or familial Mediterranean fever
  • Males > females
Etiology
  • Due to systemic amyloidosis (majority arise in secondary AA amyloidosis)
  • Secondary AA amyloidosis occurs as a result of chronic inflammatory conditions such as rheumatoid arthritis, Crohn's disease, familial Mediterranean fever, osteomyelitis or tuberculosis, resulting in increase in serum amyloid protein
  • Also reported in dialysis dependent chronic renal failure patients as a result of beta-2-microglobulin accumulation (Case Rep Endocrinol 2012;2012:741754)
Clinical features
  • Nontender, diffuse enlargement of gland over weeks to months
  • May have obstructive symptoms of dyspnea, hoarseness, dysphagia
  • Patients usually have normal thyroid function tests (euthyroid); minority have hyperthyroidism or hypothyroidism
Diagnosis
  • Fine needle aspiration cytology
  • Thyroidectomy for definitive diagnosis
Laboratory
  • Majority have normal thyroid function tests (euthyroid)
  • Minority have hyperthyroidism, hypothyroidism or thyroid autoantibodies
Radiology description
  • Ultrasound: enlargement with high echogenicity and very fine homogenous echotexture similar to ground glass appearance (J Clin Ultrasound 1994;22:239)
Case reports
Treatment
  • Treatment of underlying systemic amyloidosis
  • Thyroidectomy to relieve pressure symptoms
  • Treat associated hypothyroidism, which may cause cardiomyopathy, gastrointestinal involvement (leading to malabsorption of oral therapy) and abnormal circulating immunoglobulins, which may interfere with hormone assays or hormone function (Head Neck 1995;17:343)
Gross description
  • Depending on the amount of amyloid deposited, thyroid gland can be soft, hard, diffuse or nodular
  • Bilateral and diffusely enlarged gland with inhomogeneous nodules, whitish tan / light brown or pale yellow
Gross images

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Enlarged and bosselated with salmon cut surface (AFIP)



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Lipomatosis and amyloidosis

Microscopic (histologic) description
  • Diffuse deposition of amorphus eosinophilic fibrillary material in perifollicular and perivascular regions, may replace thyroid follicles
  • Other associated findings: fatty metaplasia, foreign body giant cell reaction, squamous metaplasia or focal lymphocytic thyroiditis
Microscopic (histologic) images

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Amyloid and inflammatory cells

Apple green birefringence

Case of Week #247



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Birefringent apple green staining under polarized light

Congo red

Calcitonin negative


Various images

Cytology description
  • Dense amorphus clumps of extracellular material or irregularly shaped fragments with scalloped and pointed edges
  • The amorphous fragments stain eosinophilic on Papanicolaou stain, magenta colored on Giemsa and deep blue with Diff-Quick cytology stain
Positive stains
  • Congo red shows salmon color and apple green dichroism with polarized light
  • The type of fibril can be determined by immunochemical staining using specific antibodies (AL and AA)
Negative stains
Differential diagnosis
  • Medullary thyroid carcinoma: calcitonin+ tumor cells present
  • Microscopic deposition of amyloid within the thyroid occurs in 59 - 92% of patients with amyloidosis; this frequency is similar between AL and AA amyloidosis (Q J Med 1974;43:127) but is not considered part of the amyloid goiter discussed here
Board review question #1
Which statement about amyloid goiter of the thyroid is false:

  1. Can be seen in renal transplant patients on dialysis
  2. Commonly seen in males
  3. Is associated with medullary thyroid carcinoma
  4. Microscopically shows diffuse deposition of amyloid
  5. Rarely presents with dysphagia, dysphonia or dyspnea
Board review answer #1
C. Is associated with medullary thyroid carcinoma

Amyloid goiter is not associated with medullary thyroid carcinoma. It is defined as amyloid deposits in thyroid associated with a goiter, but not with a malignant neoplasm.