Thyroid Tumors

Benign
1. Types
  1. Follicular Adenoma
    1. "Cold"
      1. Almost all are cold
        May still produce worrisome symptoms
        Compression of trachea
        Dysphagia
    2. "Hot"
      1. Functioning
        Clinical Findings
        Increased radioactive iodine uptake
        May have signs of hyperthyroidism
    3. Subtypes
      1. Macro (colloid)
      2. Normo
      3. Micro
      4. Trabecular
    4. General
      1. Most common benign thyroid tumor
      2. Encapsulated tumor with follicular differentiation
      3. Very low malignant potential
      4. Almost always solitary
    5. Treatment
      1. Partial or complete thyroidectomy
  2. Solitary Nodule
  3. Granular Cell Tumor
Malignant
1. Types
  1. Papillary Carcinoma
    1. General
      1. Most common thyroid malignancy
      2. F>M, 3:1
      3. a/w childhood radiation exposure
      4. Excellent prognosis
    2. Gross and Microscopic Findings
      1. Multifocal
      2. Empty appearing nuclei
        Orphan Annie eyes
      3. Papillary projections within glandular space
      4. Psamomma bodies
        Collection of calcified cancer cells; stain deep purple
      5. Lymphatic invasion
        Mets to cervical LNs and lung
    3. Diagnosis and Treatment
      1. Dx: FNA
      2. Partial or complete thyroidectomy
        Followed by radiotherapy with radioactive Iodine
      3. Suppression therapy
        levothyroxine to increase negative feedback on TSH secretion
        Shrinks the tumor
  2. Follicular Carcinoma
    1. General
      1. F>M
      2. Good prognosis
      3. a/w radiation exposure (less so than papillary) and iodine deficiency
    2. Gross and Microscopic Findings
      1. Usually a single cold, encapsulated nodule
      2. Haematogenous spread
        Annotations:
        Rather than lymphatic spread as seen in papillary carcinoma
        Mets to lung and bone first
      3. Well-differentiated, uniform follicles
      4. No psamomma bodies
      5. Widely invasive or minimally invasive classification
        Annotations:
        Minimally invasive: capsule invasion only (may have some vascular invasion of a few small vessels) Widely invasive: extends through capsule and into thyroid parenchyma and vasculature
    3. Hurthle cell carcinoma often considered a variant
    4. Diagnosis and Treatment
      1. FNA is NOT diagnostic
        Microscopically the same as follicular adenoma
        Need evidence of invasion
      2. Definitive dx requires lobectomy
      3. Treated similarly to papillary carcinoma
  3. Medullary Carcinoma
    1. Findings
      1. Increased serum calcitonin
        Causes diarrhoea
        Tumor marker
      2. May have ectopic hormone production, paraneoplastic syndromes
        Ex. ACTH causing Cushing syndrome
      3. Calcitonin amyloid material in stroma
      4. Mets
        Early regional LN mets common
        Distant mets to liver, lung, bone and brain
    2. Diagnosis and Treatment
      1. Dx: FNA, increased calcitonin
      2. Total thyroidectomy and genetic screening of RET gene if familial
    3. General
      1. Neuroendocrine tumor of parafollicular C cells
        C-cell hyperplasia is a precursor lesion
      2. Causes
        Sporadic (80%)
        Poorer prognosis than familial type
        Unilateral
        Familial (20%)
        a/w MEN 2A and 2B
        Annotations:
        Recall: MEN 2A- medullary carcinoma, hyperparathyroidism, pheochromocytoma MEN 2B- medullary carcinoma, mucosal neuromas, pheochromocytoma
        Younger patients
        Bilateral and multicentric
  4. Anaplastic
    1. General
      1. Elderly women
      2. a/w multinodular goiter and positive follicular cancer history
      3. Rapidly aggressive
        VERY poor prognosis
        Early dissemination
        Invasion of local structures (trachea, oesophagus) common
        50% have lung mets at presentation
    2. Gross and Microscopic Findings
      1. Regions of spontaneous haemorrhage and necrosis
      2. Infiltration of adjacent structures
    3. Diagnosis and Treatment
      1. Dx: FNA or surgery if inconclusive
      2. Palliative treatment
        Partial surgical resection
        Tumor often compresses the trachea
        Extensive resection of tumor and surrounding structures generally NOT indicated
        High post-op morbidity
        Ex. vocal cord paralysis
        No proven survival benefit
        Chemo or radiation
  5. Primary B Cell Lymphoma
    1. Most commonly a/w Hashimoto's thyroiditis

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Thyroid Tumors

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	Created by Gdubs almost 10 years ago