Goiter By Dr. Abdelaty Shawky assistant professor of pathology

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GoiterBy Dr. Abdelaty Shawkyassistant
professor of pathology
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• Definition Non-inflammatory, non-neoplastic
  enlargement of the thyroid gland.
• Classification
• Simple (non-toxic) goiter.
• Toxic goiter.

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SIMPLE (NON-TOXIC) GOITER

• Enlargement of the thyroid without toxic
  manifestations.
• Causes
• 1. Iodine deficiency.
• a. Absolute deficiency in areas far from the
  sea.
• b. Relative deficiency due to increased demand
  for iodine at pregnancy, puberty and lactation.
• 2. Dyshormonogenesis hereditary deficiency of
  enzymes necessary for thyroxine formation.
• 3. Goitrogens Well-known goitrogens as cabbage,
  cauliflower which contain thiocyanate which
  inhibits iodide transport within the thyroid.

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Pathogenesis

• a. Parenchymatous goiter
• Iodine deficiency ? decreased thyroid hormone
  synthesis ? increases TSH secretion ? thyroid
  glands hyperplasia.
• The acini are increased in number and lined by
  tall columnar cells and contain little colloid.
• If iodine deficiency is corrected after a short
  time, the acini return to the normal state.

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• b. Colloid goiter
• When iodine deficiency is corrected after a
  longer time ? the acini are distended with
  colloid and lined by flat cells.
• c. Nodular goiter
• Repeated cycles of iodine deficiency correction
  ?nodular goiter in which the gland shows multiple
  nodules of parenchymatous goiter, colloid goiter
  and areas of fibrosis.

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Morphological features

• a. Parenchymatous goiter
• Gross picture
• Symmetrical enlargement.
• Firm in consistency.
• Cut surface is grayish pink.

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• Microscopic picture
• Hyperplastic acini lined by tall columnar cells
  and filled with scanty colloid.

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• b. Colloid goiter
• Gross features
• Symmetrical enlargement.
• Soft in consistency.
• Cut surface is grayish brown in color and may
  shows cystic spaces filled with glistening
  colloid honey comb appearance.

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• Microscopic picture
• The acini are distended with colloid and lined by
  flat cells.
• The stroma is scanty.

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• c. Nodular goiter
• Gross picture
• Asymmetrical enlargement.
• Variable firm areas and soft cystic areas.
• Cut surface is nodular.

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• Microscopic picture
• Multiple nodules, some formed of hyperplastic
  acini and others show acini filled with colloid.
• The nodules are surrounded by fibrous tissue.

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Complications of simple goiter

• 1. Pressure effects on esophagus, trachea, and
  recurrent laryngeal nerve.
• 2. Secondary hyperthyroidism due to
  Hyperfunctioning nodules (toxic nodular goiter).
  No exophthalmos.
• 3. Malignancy in 2 of cases follicular
  carcinoma.

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Goiter
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Goiter
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Goiter
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Toxic goiter

• Two types
• 1. Primary toxic goiter (exophthalmoic goiter or
  graves disease).
• 2. Secondary toxic goiter toxic nodular goiter
  or toxic adenoma.

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Primary toxic goiter exophthalmic goiter
(graves disease)
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• Organ specific autoimmune disease due to
  auto-antibodies (LATS long acting thyroid
  stimulating) stimulating TSH receptors leads to
  diffuse hyperplasia and hyperfunctioning acini
  with excess thyroid hormone secretion

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• Pathological features
• 1. Thyroid
• N/E symmetrically enlarged, firm, with dark red
  vascular cut surface.
• M/P hyperplastic acini lined by columnar cells
  and filled with faintly stained colloid with
  peripheral scalloping. The stroma is highly
  vascular and shows lymphocytic infiltration.

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Graves disease Diffusely enlarged gland , Can
weigh up to 200 g ,Richly vascular
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Toxic goiter
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Toxic goiterscalloping of colloid inside
thyroid folliclessmall sized follicles ,
lymphocytic infiltration,hypervascularity
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• 2. Exophthalmos forward protrusion of the eye
  globe due to edema and degeneration of the
  retro-orbital muscles special auto-antibodies
  react with them.
• 3. Diffuse lymphoid hyperplasia in thymus,
  tonsil, spleen, guts.
• 4. Left ventricular hypertrophy thyrotoxic
  cardiomyopathy.
• 5. Pre-tibial myxedema.
• 6. Increased basal metabolic rate

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Exophthalmos associating Graves disease
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Exophthalmos associating toxic goiter
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• Secondary toxic goiter

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• Causes
• A. Toxic nodular goiter
• Complicating simple nodular goiter.
• Diffuse, nodular enlargement of the thyroid. Some
  nodules show hyperfunctioning acini. Other acini
  are inactive.
• B. Toxic adenoma
• Complicating thyroid adenoma.
• The Hyperfunctioning neoplastic acini are like
  those of graves disease. The remaining thyroid
  tissue is inactive. Thyroid hormone secretion is
  autonomous.

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Thyroiditis
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• Inflammation of the thyroid.
• Types
• 1. Hashimotos thyroiditis.
• 2. Subacute granulomatous thyroiditis (DeQuervain
  thyroiditis).
• 3. Reidels (fibrous) thyroiditis.

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hashimoto thyroiditis

• Occurs in middle old age.
• Common in females more than males (201).
• Cause painless thyroid enlargement.
• Associated with hypothyroidism.
• Pathogenesis
• Autoimmune disease in which the immune system
  reacts against a variety of thyroid antigens.

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• Gross picture
• Symmetrically enlarged thyroid gland.
• Firm inconsistency.
• Intact, non-adherent capsule.
• Cut surface is pale, homogenous and sometimes
  nodular.

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Hashimoto thyroiditis
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• Microscopic picture
• Dense inflammatory infiltrate formed of
  lymphocytes, plasma cells and macrophages, with
  sometimes lymphoid follicle formation.
• Some acini are atrophied and others show
  regenerative changes (lined by large cubical
  cells with deeply esinophilic granular cytoplasm
  termed (Hurthle cells). This is termed Hurthle
  cell metaplasia.
• Finally, fibrosis.

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Hashimoto thyroiditis
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Hashimoto thyroiditis Hurthle cell metaplasia
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Hashimoto thyroiditis Hurthle cell metaplasia
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• Complications
• Hypothyroidism.
• Development of other autoimmune diseases.
• Malignant transformation (lymphoma)

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Subacute granulomatous thyroiditis

• Occurs between 30-50 years.
• More common in females than males (51).
• Cause painful thyroid enlargement.
• Associated with transient hyperthyroidism.
• Pathogenesis
• Associated with viral infection.

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• Gross picture
• Unilateral or bilateral enlargement.
• Intact capsule.
• Slightly adherent.
• Cut surface shows scattered firm yellowish white
  areas.

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• Microscopic picture
• Neutrophilic infiltration with variable
  destruction of the thyroid follicles.
• Pools of colloid surrounded by multinucleate
  giant cells, aggregations of lymphocytes,
  histiocytes and plasma cells.
• Finally, fibrosis, chronic inflammatory cells
  replace the damaged foci.

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Granulomatous thyroiditis
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Reidels thyroiditis

• Rare, of unknown cause. Affect both sexes
  equally.
• Gross picture
• The gland is hard in consistency and adherent to
  the surrounding structures (simulating
  malignancy).
• Microscopic picture
• Dense fibrous tissue replacing the thyroid tissue
  and penetrating the capsule to the surrounding
  neck structures.