Endocrine Neoplasia

• Fill in the blanks

  A) Follicular cell

  B) Parafollicular cell

  C) Stroma

  D) Colloid

  
• What is a thyroid nodule?

  A growth or lump in the thyroid gland

  Palpable/visible swelling

  Incidence = 1-10% (USA)

  Pressure symptoms

  Pain

  
• What is important in the Hx & examination of a neck lump?

  Duration

  RFs -> irradiation to head & neck

  FHx (MEN syndrome)

  Concerning features -> rapid growth, pressure symptoms, hoarse voice

  Fixed & hard lump?

  Lymphadenopathy?

  Signs of hyper or hypothyroidism
• Where is the thyroid gland located?

  Anterior to larynx
• What is thyroid scintigraphy?

  Imaging used to investigate functioning of nodules

  • hot nodule = increased uptake
  • cold nodule = reduced uptake

  Hot nodules are more likely to be benign
• What is the gold standard test for evaluation of thyroid nodule?

  Fine needle aspiration cytology
• Thyroid cytology results

  Thy 1 -> non-diagnostic

  Thy 2 -> benign

  Thy 3a -> atypia of undetermined significance

  Thy 3f -> follicular neoplasm

  Thy 4 -> suspicious for malignancy

  Thy 5 -> malignant
• What is the most common type of thyroid cancer?

  Papillary thyroid carcinoma
• Types of thyroid neoplasia

  Benign

  • thyroid adenoma
  • follicular adenoma

  Malignant

  • follicular thyroid carcinoma
  • papillary thyroid carcinoma
  • medullary carcinoma
  • anaplastic carcinoma
• What is more indicative of malignancy, a solitary thyroid nodule or multiple?

  Solitary (esp in a younger individual, more common in females)
• Papillary thyroid carcinoma

  Most common thyroid cancer (85%)

  Can be solitary or multifocal

  Can be well-circumscribed or encapsulated or infiltrative

  Commonly spreads to cervical lymph nodes

  Under microscopy

  • branching papillae
  • clear/empty looking nuclei ('Orphan Annie Eye' nuclei)

  
• Thyroid/follicular adenoma

  Benign

  Presentation: solitary painless lump, if large can have pressure symptoms & difficulty swallowing

  Inx: radioiodine scan ('cold nodule'), FNAC (Thy3f)

  Treatment: excised with capsule intact
• Follicular carcinoma

  Malignant thyroid tumour (5-15%)

  Presentation: solitary nodule, slowly enlarging

  Usually 'cold' on scintigraphy but may be 'warm'

  Tends to invade vasculature

  Treatment: total thyroidectomy + radioactive iodine
• Anaplastic carcinoma of the thyroid

  Aggressive tumour

  Mean age = 65 yrs

  Very high mortality rate (nearly 100%)

  Invasion of neck structures -> dyspnoea, dysphagia, hoarseness, cough
• Medullary carcinoma of the thyroid

  Cancer from parafollicular cells (neuroendocrine)

  70% are sporadic, but associated with MEN 2A/2B

  Elevated calcitonin levels

  'speckles' of chromatin in nuclei

  
• MEN

  Multiple endocrine neoplasia

  Autosomal dominant

  Proliferative/neoplastic disorders in multiple endocrine organs

  Tumours occur at younger age

  Types

  • MEN 1 -> menin gene (chromosome 11), inactivating mutation
  • MEN 2A/2B -> RET proto-oncogene, gain of function mutation
• MEN 1

  Affects the 3 Ps

  • parathyroid adenoma
  • pituitary adenoma
  • pancreas endocrine tumours

  Causes primary hyperparathyroidism (hypercalcaemia), gastrinomas (peptic ulcers), insulinomas (hypoglycaemia)
• MEN 2A

  Parathyroid adenoma

  Medullary thyroid carcinoma

  Bilateral phaeochromocytoma
• MEN 2B

  Medullary carcinoma of the thyroid

  Neuromas (in tongue & lips)

  Phaeochromocytoma
• Lactrotrophy (prolactin) adenoma

  Functioning pituitary adenoma

  Presentation: amenorrhea, galactorrhea, loss of libido, infertility
• Somatotroph (growth hormone) adenoma

  Functioning pituitary adenoma

  Presentation: gigantism (children), acromegaly (adults), impaired glucose tolerance/diabetes
• How do non-functioning pituitary adenomas present?

  Bitemporal hemianopia
• How does phaeochromocytoma present? How is it diagnosed?

  HTN

  Palpitations

  Tachycardia

  Headache

  Sweating

  Anxiety

  Tremor

  Diagnosis = urinary free catecholamines