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Three methods are currently used in the assessment of thyroid nodules. This is fine needle aspiration or FNA, thyroid scans, and ultrasound. Of these three first FNA should be more diagnostically useful and cost effective. Although ultrasound may be able to nodules, which are not detected by scanning to detect, it is still not able to distinguish between benign and malignant nodes. Thyroid scans can be misleading in the interpretation of malignancy of thyroid nodules.

FineAspiration biopsy is a technique whereby a sample of tissue is evaluated to be removed with a thin needle. For superficial tissue in the thyroid, breast and prostate, the needle is unguided, but for deeper tissue must radiologically guided needle.

The normal thyroid gland under the microscope

Unlike other endocrine glands, the thyroid gland by providing unique extracellular memory for its products in cystic follicles. These follicles containThyroid hormones well enough for several weeks. They are almost spherical in shape and surrounded by a layer of cubical cells. These follicles ranging from 0.2 to 0.9 mm in diameter and are filled with a substance called colloid.

Some cytophathologists think there must be at least six groups of follicular cells 10 to 20 cells each on two films for a biopsy of the thyroid to be benign. The diagnosis of malignancy can be made if there are fewer cells whenthat there are other signs of malignant disease in the sample.

Cytopathologic Features

Thyroid fine-needle aspiration can be difficult and challenging as the amount of tissue on the slides for examination may be from the nature of the air supply. However, should the assessment of thyroid tissue include the following:

The presence or absence of follicles
Cell size
Staining properties of the cells
Tissue polarity. This should be taken into consideration in the cellBlock only copies.
Presence of nuclear grooves and / or nuclear clearing
Presence of nucleoli
Presence and nature of colloid —
Monotonous population either follicular or Hürthle cell
Presence of lymphocytes

Benign Lesions

Nearly seventy percent of cases of thyroid masses are benign lesions. Although the clinical symptoms in a patient benign lesions may favor, FNA is not really that FNA should be excluded in the workup. These are the following clinicalCharacteristics of benign lesions of the thyroid:

A sudden onset of pain and tenderness may indicate bleeding into a benign adenoma or cyst, or subacute granulomatous thyroiditis, respectively. However, bleeding may present with similar signs of a cancer.
Symptoms of hyperthyroidism and autoimmune thyroiditis (Hashimoto disease).
Family history of benign nodular disease, Hashimoto's disease, or autoimmune thyroiditis.
A smooth, soft andeasily movable nodes.
Multi-nodularity.
A midline knots over the hyoid bone that moves and with the projection of the tongue is probably a thyroglossal cyst.

Cytologic and laboratory features of benign thyroid nodules are the following:

The presence of abundant watery colloid.
Foamy macrophages.
Cyst or cysts, degeneration of a tight knot.
Hyperplastic nodules.
Abnormal TSH levels.
Lymphocytes and / or high thyroid peroxidase antibodyLevels. This might indicate, Hashimoto's disease, or in rare cases a lymphoma.

Malignant lesions

Papillary carcinoma

Papillary carcinoma accounts for about eighty percent of all malignant diseases of the thyroid. This type of malignancy include papillary and follicular variants such as the large cell variant and the sclerosing variant mixed. Two or more of the following characteristics are suggestive of cytological papilla:

nuclear inclusions,"cleared out", "ground glass" or "Orphan Annie" nuclei
nuclear "Grooves"
overlapping nuclei
Psammoma bodies (which is rare)
papillary projections with fibrovascular core
"miserable" Colloids

Follicular, or Hürthle Cell Tumors

The lesions in this diagnostic category express characteristics that are signs of malignancy, but are not really diagnostic. Factors that are of malignancy included male sex, a node larger than 3 centimeters, andAge of more than 40 years.

The definitive diagnosis requires the histological examination of the node for capsular or vascular invasion seen. There are no genetic, histological or biochemical tests so far, are routinely used to distinguish between benign or malignant change in this category. Several studies show that thyroid expression, as measured by the monoclonal antibody mAb-47 improves the specificity of correctly distinguishing between benign and malignant neoplasmsin FNA specimens. Galectin-3 was also observed that very diffuse and are expressed in follicular neoplasms, but only minimally expressed in favorable conditions.

Cytological and histological features of malignant follicular include:

Minimal amounts of free colloidal
High-density cell population, either follicular or Hürthle cell
microfollicles

Cytologically, these lesions are reported as:

"Hürthle cell neoplasm"
"Suspicious for follicularNeoplasm "
"Follicular neoplasm / Changes"
"Indeterminate" or "non-diagnostic"

Carcinoma

Fifteen percent of the malignant thyroid diseases are defined in this category. This type of thyroid malignancy should be in patients with a family history of medullary cancer or suspicion of multiple endocrine neoplasia type 2

Cytological or histological features include the following:

Spindle cells with eccentric nuclei
positive calcitonin stain
Presence of amyloid
Inclusions (the usual) are

Anaplastic carcinoma

In less than one percent of patients with malignant lesions of the thyroid, the diagnosis of anaplastic carcinoma. This type of malignancy is more common in elderly patients with a rapidly growing mass of the thyroid. These patients have a slowly growing mass for many years already. It is important that anaplastic carcinoma, which has limited treatment are, of thyroid lymphoma, a differentiatedwhich there are available treatments.

Cytologic features of anaplastic carcinoma include the following:

extreme cellular pleomorphism
multinucleated cells
Giant cells

Thyroid lymphoma

This is a rare form of malignant diseases of the thyroid. Rapid growth of the neck mass in the position of the thyroid gland in an elderly patient, is particularly evident in someone with Hashimoto's thyroiditis, thyroid lymphoma suggestive. Cytological features that could furtherthis diagnosis are:

monomorphic pattern of lymphoid cells
positive B-cell immunotyping

Although fine-needle aspiration of the thyroid gland is an important technique in the assessment of changes in the thyroid, a patient is always free to ask for a second opinion, especially for something as serious as thyroid carcinoma. As was mentioned, it is also important to distinguish the test pathologist or cytologist between different tumors. A prompt and correctDiagnosis could spell the difference between a quality of life, disability or even death.

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