FNA of the Thyroid

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FNA of the Thyroid

• Lisa Kendrick BSc., RT Cytology, CT (ASCP)
• School of Diagnostic Cytology
• Health Sciences Centre

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Objectives

• Describe the anatomy of the thyroid.
• Describe the histologic features of the thyroid
• List and describe the normal cytologic features
  of the thyroid.
• State the requirement of adequacy for a FNA of
  the thyroid.
• List and describe the common benign conditions of
  the thyroid.
• List and describe the common malignancies of the
  thyroid.
• List and describe the common metastatic
  malignancies of the thyroid.
• Discuss the various methods of treatment of
  malignancies of the thyroid.

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Anatomy

• Located below the larynx
• Consists of two lobes that lie on either side of
  the trachea
• Lobes are connected by an ithmus
• Is an endocrine gland
• Concepts of Human Anatomy and Physiology, Van de
  Graff and Fox, page 504, Figure 19.13

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Histology

• Consists of spherical sacs thyroid follicles
• Lined by simple cuboidal epithelium
• Contains colloid
• Wheaters Functional Histology 3rd Edition,
  Burkitt, Young and Heath, page 310, Figure 17.7

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Thyroid - Histology
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Cells of the Thyroid
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Follicular Cells

• Nucleus
• Central
• Round/oval
• Finely granular chromatin
• 1 2 nucleoli
• Cytoplasm
• Pale
• Indistinct
• Arrangement
• Honeycomb pattern

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Hurthle Cells

• AKA Askanazy cells or Oncocytes
• Large, polygonal cells
• Nucleus
• Round/oval
• Eccentric
• Finely granular chromatin
• Cytoplasm
• Abundant
• Granular
• Eosinophilic

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Colloid

• Found in the background
• May stain blue, pink or metachromatic
• Two states
• Watery Thick

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Satisfactory Specimen

• 5 or more groups of 10 cells each on a minimum of
  2 slides

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Benign Conditions of the Thyroid
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Colloid Nodule

• Most common form of goiter in adolescents and
  young women
• Follicular cells cease to proliferate and colloid
  accumulates within the follicles

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Colloid Nodule

• Cytology
• Macrofollicular pattern
• Variable cellularity
• Hurthle cell change may
• be seen
• Scant follicular cells (normal in appearance)
• Macrophages
• Abundant colloid

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Cystic Degeneration

• FNA can cure 20 60 of cystic lesions by
  evacuation
• Cytology
• Few follicular cells
• Abundant macrophages

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Hashimotos Thyroiditis

• AKA chronic thyroiditis
• An autoimmune disorder
• Affects women more than men
• Associated with hyperthyroidism

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Hashimotos Thyroiditis

• Cytology
• Cellular aspirate presenting
• in small groups, fragments
• Groups of Hurthle cells
• Follicular cells with Hurthle cell
• change
• Inflammatory cells (lymphocytes and macrophages)
• Tingible body macrophages
• Little colloid
• Possible lymphoma
• association

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Malignancies of the Thyroid
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Follicular Carcinoma

• Peak onset ages 40 through 60
• Females more common than males by 3 to 1 ratio
• Prognosis directly related to tumor size less
  than 1.0 cm (3/8 inch) good prognosis
• Rarely associated with radiation exposure
• Spread to lymph nodes is uncommon (10)
• Invasion into vascular structures (veins and
  arteries) within the thyroid gland is common
• Distant spread (to lungs or bones) is uncommon,
  but more common than with papillary cancer
• Overall cure rate high (near 95 for small
  lesions in young patients), decreases with
  advanced age
• www.endocrineweb.com/capap.html

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Follicular Carcinoma

• Distinction between neoplasm and carcinoma
  depends on the histology specimen
• Identification of invasion of either the capsule
  or blood vessels confirms the diagnosis of
  carcinoma
• It is very difficult to differentiate between
  neoplasm and carcinoma based on morphology alone

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Follicular Neoplasms

• The cellularity varies
• No colloid
• Cells are arranged in small, loosely cohesive
  groups
• Micro follicular pattern is observed
• Syncytial patterns predominate
• There may be overlap of some features with a
  colloid nodule

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Follicular Neoplasm

• Nucleus
• Round
• Smooth membrane
• Fine/coarse even chromatin
• Macronucleoli
• Cytoplasm
• Pale
• Poorly defined

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Papillary Carcinoma

• Peak onset ages 30 through 50
• Females more common than males by 3 to 1 ratio
• Prognosis directly related to tumor size less
  than 1.5 cm (1/2 inch) good prognosis
• Accounts for 85 of thyroid cancers due to
  radiation exposure
• Spread to lymph nodes of the neck present in more
  than 50 of cases
• Distant spread (to lungs or bones) is very
  uncommon
• Overall cure rate very high (near 100 for small
  lesions in young patients)
• www.endocrineweb.com/capap.html

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Papillary Carcinoma

• Highly variable cellularity
• (very cellular to scant or cystic)
• Little to no colloid
• Papillary arrangements or monolayered fragments
• Syncytia may be present
• Enlarged polygonal cells

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Papillary Carcinoma

• Nucleus
• Central
• Overlapping
• Round/oval/pleomorphic/
• angulated
• Finely granular (powdery) chromatin
• Micro or macro nucleoli
• Folds and creases (grooves)
• Cytoplasmic nuclear inclusions
• Abundant cytoplasm
• Psammoma bodies may be present
• Multinucleated macrophages

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Hurthle Cell Neoplasm

• Cellularity varies
• Little to no colloid
• Cells are dispersed or arranged in loose
  monolayers
• May be follicular growth pattern
• Monomorphic population of Hurthle cells
• May have red macronucleoli
• May demonstrate binucleation
• May demonstrate nuclear grooving

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Hurthle Cell Neoplasm

• There is no clear separation between adenomas and
  carcinoma
• However if the following features are present a
  carcinoma may be suspected
• Hypercellularity
• Syncytia
• Increased NC
• Nuclear pleomorphism
• Multinucleoli

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Medullary Carcinoma

• Occurs in 4 clinical settings and can be
  associated with other endocrine tumors
• Females more common than males (except for
  inherited cancers)
• Regional metastases (spread to neck lymph nodes)
  occurs early in the disease
• Spread to distant organs (metastasis) occurs late
  and can be to the liver, bone, brain, and adrenal
  medulla
• Not associated with radiation exposure
• Usually originates in the upper central lobe of
  the thyroid
• Poor prognostic factors include age gt50, male,
  distant spread (metastases), and when seen in
  patients with other endocrine tumors due to MEN
  II-B syndrome.
• Residual disease (following surgery) or
  recurrence can be detected by measuring
  calcitonin (a hormone that should be measured
  every 4 months for the first few years and then
  every 6 months for ever).
• www.endocrineweb.com/capap.html

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4 Variants

• Sporadic
• MEN II-A (Sipple Syndrome)
• MEN II-B
• Inherited Medullary Carcinoma

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Medullary Carcinoma

• Not a common malignancy
• Can be multifocal (in which the clinician may
  remove the entire thyroid)
• Lymph node involvement is common

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Medullary Carcinoma

• Cellularity varies
• Cell morphology varies
• Plasmacytoid
• Round
• Polygonal
• Spindle
• Arranged in loose groups
• Single cells are common
• Amyloid may be present in the background

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Medullary Carcinoma

• Nuclei
• Oval/pleomorphic
• Coarse salt and pepper chromatin pattern
• Central or eccentrically located
• Indistinct nucleoli
• Binucleation may be seen
• Intranuclear inclusions may be seen
• Cytoplasm is finely granular

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Anaplastic Carcinoma

• Very rare
• Diagnosis is often suggested by clinical findings

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• Peak onset age 65 and older
• Very rare in young patients
• Females more common than in males
• Typically presents as rapidly growing neck mass
• Can occur many years after radiation exposure
• Spread to lymph nodes of the neck present in more
  than 90 of cases
• Distant spread (to lungs or bones) is very common
  even when first diagnosed
• Overall cure rate very low
• Typically requires a very aggressive treatment
  plan with surgery, radiation and sometimes even
  chemotherapy.
• Often requires the patient to get a tracheostomy
  to maintain their airway.
• www.endocrineweb.com/capap.html

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Anaplastic Carcinoma

• Giant or mixed forms
• Variable cellularity
• Inflammatory cells and necrotic debris are found
  in the background
• Variable cell morphology
• Squamoid
• Giant cell
• Spindle cell

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Anaplastic Carcinoma

• Nucleus
• Pleomorphic in shape
• Irregular membrane
• Coarse, irregularly distributed chromatin
• Prominent nucleoli
• Atypical mitosis
• Multinucleation
• Cytoplasm
• Densely granular

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Metastatic Malignancies
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Metastatic Malignancies

• Thyroid is a common site for metastases
• Common metastatic tumors include
• Adenocarcinoma of the breast
• Renal cell carcinoma
• Squamous cell carcinoma from elsewhere
• Melanoma
• Lymphoma

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Metastatic Melanoma

• Cells are very pleomorphic
• Pigment is often not present
• Clinical history is very important
• Immunohistochemistry aids in the diagnosis (S100,
  HMB45)

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Lymphoma

• Non-Hodgkins Hodgkins
• monotonous population - Lymphoid cells and
  of lymphoid cells Reed-Sternberg cells

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Treatment Methods
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Surgery

• Two types
• 1. Lobectomy
• The entire thyroid is removed.
• 2. Hemithyroidectomy (lobectomy)
• The surgeon removes the entire lobe on the side
  of the thyroid where the growth or cancer is
  found. If a biopsy of the growth confirms cancer,
  the surgeon may also remove the other lobe.

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Radiation Therapy

• Three types of radiation therapy
• 1. External beam radiation therapy - In external
  beam radiation therapy,
• radiation is directed at the cancer
  and surrounding tissue from a machine
• outside the body. It is used to treat
  most types of cancer.
• 2. Brachytherapy - treats the cancer with a high
  total dose
• of radiation in a concentrated area
  in a short period of time. Sealed
• radioactive sources are placed in the
  body, in or near the cancer. A
• sealed radioactive source is often
  called an implant.
• 3. Systemic radiation therapy - the radiation
  source is given as a liquid
• (either as a drink or in capsules
  that are swallowed) or by injecting it into a
• vein (an intravenous injection). The
  radiation source travels throughout
• the body.

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Radioactive Iodine Therapy (RAI)

• Radioactive iodine (also called iodine-131 or
  I-131) is commonly used to treat thyroid cancer.
  It is given either as a drink or as a capsule.
  Thyroid cells and cancer cells absorb the
  radioactive iodine. It destroys any cancer cells
  and normal thyroid cells that may still be in the
  body after surgery.
• After radioactive iodine therapy, thyroid hormone
  replacement therapy is required to replace the
  hormone  that was made by the thyroid cells.

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Thyroid Hormone Treatment

• Thyroid hormone therapy is sometimes used to
  treat papillary or follicular thyroid cancer. It
  is given as pills. The hormone thyroxine (T4)
  slows the growth of thyroid cancer cells that may
  be left in the body after surgery.

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Classification and Staging
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TMN Classification (T tumor, N node, M
metastases

• T1 lt 1cm, limited to thyroid
• T2 gt 1cm, lt 4cm, limited to thyroid
• T3 gt 4cm, limited to thyroid
• T4 extension beyond capsule
• N1a - Ipsilateral cervical
• N1b Bilateral/midline/contralateral/cervical
  /mediastinal
• M0 no metastases
• M1 - metastases

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Stage Grouping Under 45 years

• STI T any, N any, M0
• STII T any, N any, M1

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Stage Grouping 45 years and older

• Stage IA T0, N any, M0
• Stage IB T1, N any, M0
• Stage II T2, N any, M0
• Stage III - T3, N any, M0
• Stage IV T any, N any, M1

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• Questions?