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Hot spots: Thyroid

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					Hot spot on thyroid
                  Definition
• A hot nodule is defined as a nodular region of
  the thyroid gland that takes up large amounts
  of radioactive iodine relative to the rest of the
  thyroid gland, hence it is visualized as a "hot
  spot" on the thyroid scan
• Autonomously function
                     Causes
• Benign Thyroid Nodules
  – Multinodular goiter
  – Hashimoto's thyroiditis
  – Thyroid cyst
• Malignant Thyroid Nodules
  – Papillary thyroid carcinoma
  – Follicular thyroid carcinoma
  – Anaplastic thyroid carcinoma
  – Medullary thyroid carcinoma
                   Symptoms
•   Hyperthyroidism
•   Difficulty swallowing
•   Shortness of breath
•   Difficulty in speaking
    – Compression of the larynx
• Other enlarged glands or lymph nodes in the
  neck
• Rapidly growing lump in the neck
               History of patient
• Detailed history of patient has to be taken
• Patient is younger than 20 or older than 70 years
   – Increased likelihood that a nodule is cancerous
• Difficulty swallowing
• Change in the voice
• Women tend to have more thyroid nodules than men,
  the nodules found in men are more likely to be
  cancerous
• Many patients with risk factors uncovered in the
  history will have benign lesions, while others without
  risk factors for malignant nodules may still have thyroid
  cancer
          Physical examination
• If the nodule is fixed to the surrounding tissue
  – probability of cancer is higher
• Any abnormal lymph nodes in the nearby area
  – spread of cancer
• Signs of gland malfunction, such as an
  overproduction or underproduction of thyroid
  hormone
 Diagnosis- Laboratory evaluation
• Sensitive thyroid-stimulating hormone (TSH)
  assay
• Serum thyroxine (T4) and triiodothyronine (T3)
  levels
• Anti-thyroid antibody
   – Indicate the presence of autoimmune thyroid
     inflammation
• Calcitonin levels
   – Indicate a specific type of thyroid cancer, known as
     medullary carcinoma of the thyroid.
       Diagnosis- Imaging studies
•   Iodine-131 whole-body scintigraphy (131I WBS)
•   Ultrasonography
•   Computed tomography (CT) scanning
•   Magnetic resonance imaging (MRI)
•   Positron emission tomography (PET) scanning
•   FDG positron emission tomography (PET)
•   Fluorine-18 fluorodeoxyglucose positron
    emission tomography
    Diagnosis- Fine needle aspiration
                  biopsy
• Sensitivity higher than 80%
• Thin needle is inserted directly into the lump
• Some cells are withdrawn and evaluated.
• Ultrasound is used to help guide the needle
  into the correct position.
• Can be used to categorize tissue into
  thyroiditis, follicular neoplasm, malignant,
  benign, suspicious, or nondiagnostic tissue
                        FNAB results
• Benign thyroid tissue (non-cancerous)
   – Consistent with Hashimoto's thyroiditis or a colloid nodule or cyst. This
     result is obtained in about 60% of biopsies.
• Cancerous tissue (malignant)
   – Papillary, follicular, or medullary cancer
   – About 5% of biopsies
   – Majority are papillary cancers
• Suspicious biopsy
   – Show follicular adenoma
   – Up to 20% of these nodules are found ultimately to be cancerous
• Non-diagnostic
   – Usually because not enough cells are obtained
   – If repeated, up to 50% of these cases will be able to be diagnosed as
     benign, cancerous, or suspicious.
                  Treatment
• Suppressive doses of thyroid hormone
• Destroying the gland using radioactive iodine
• When a nodule is hyperfunctioning and the
  TSH is minimally suppressed, but the level of
  thyroid hormones in the blood is not elevated
  – Treatment is individualized based on the patients
                     Surgery
• Partial or complete thyroidectomy when:

  – Thyroid cancer or indeterminate lesions that cannot
    be classified from a fine needle aspiration biopsy
  – Large thyroid nodules that cause obstructive
    symptoms, such as problems breathing or swallowing
  – Thyroid nodules cause pain

				
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posted:5/31/2011
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