Sorting out Thyroid nodules

Dr. Kofo O. SoyebiCMUL/LUTH

Outline

• Introduction• Criteria for characterization• Imaging modalities• Symptoms• Differential Diagnosis

Introduction• The term thyroid nodule refers to an abnormal

growth of thyroid cells that forms a lump within the thyroid gland.

• The vast majority of thyroid nodules are benign (noncancerous), a small proportion of thyroid nodules do contain thyroid cancer.

• Evaluation of these nodules is necessary to characterize and determine modalities of management

• If the odds that the nodule is not a cancer, only the side of the thyroid with the nodule is usually removed. If a cancer is found, the remaining thyroid gland usually must be removed as well. If the surgery confirms that no cancer is present, no additional surgery to “complete” the thyroidectomy is necessary.

Symptoms• Most thyroid nodules do not cause symptoms. • Individual patients’ observation• Neck mass• +/_ Difficulty in swallowing or choking sensations

Signs

• Elevation of values of biochemical• Observation by Physicians

* Radiographic: neck +/_ retrosternal extension* Sonographic or round or oval masses (hypoechoic, hyperechoic, mixed echogenicity, cystic)* CT* MRI

Criteria for characterization• Symptoms• Signs• Radiologic findings

* Position* Shape* Size*Outline* Density* Number

• Laboratory findings

Imaging modalities• Plain Radiography• Ultrasonography• CT• MRI• Scintigraphy• Thyroid fine needle aspiration biopsy (FNA or

FNAB) - This result is obtained in up to 80% of biopsies. The risk of overlooking a cancer when the biopsy is benign is generally less than 3 in 100 tests or 3%. This is even lower when the biopsy is reviewed by an experienced pathologist at a major medical center.

• Molecular diagnostics

Plain radiography

• Not very useful in evaluating nodules.• Can however assess extent of huge thyroid glands

* Effect on trachea* Extent of growth - ? Retrosternal extension* ? calcifications

USS

• Safe, therefore useful for the very necessary repeat and follow-up studies

• Clearly defines density, margin and other characters of the nodules

• Useful in guiding the needle in fine needle biopsy

USS + FNAC

• Combination of thyroid ultrasound and biopsy have proven so accurate and sensitive and therefore very reliable

CT , MRI

• Valuable for determining extent of spread of malignant nodules

Scintigraphy

• Useful in unusual cases• Rarely used now-a-days though• Useful for detecting ectopic tissues

Molecular Genetics in Diagnosis• Still mainly research interests• Not widely available new tests that examine genes

in the DNA of thyroid nodules are being developed. • These tests can provide helpful information about

whether cancer may be present or absent. • Useful if indeterminate nodules are being dealt

with. • These specialized tests are done on samples

obtained during the normal biopsy process. • There are also specialized blood tests that can assist

in the evaluation of thyroid nodules.

Differential Diagnosis

• Benign• Malignant• Indeterminate

Benign Thyroid nodules

• Make up about 80% of thyroid nodules• Can be singular, multiple, limited to one lobe or

wider spread• Rate of growth is important• Follow up ultrasound examinations are important.• More than one biopsy may be required over time

especially if the nodule grows significantly during the period.

Malignant

• malignant nodules make up about 5% all thyroid nodules.

• Most often due to papillary cancer, which is the most common type of thyroid cancer.

• Mixed echogenicity, irregular outline, usually solitary, large in size, lymphadenopathy

• A suspicious biopsy has a 50-75% risk of cancer in the nodule.

Indeterminate• Defn: An Indeterminate nodule is one that has no

definitive feature and at FNAC even with adequate number of cells harvested during the fine needle biopsy, examination with a microscope cannot reliably classify the result as benign or malignant. * The nodule may be indeterminate because the nodule is described as a Follicular Lesion.

• This is an FNAC Dx.• About 20% of cases fall into this group. • These nodules are cancerous 20- 30% of the time. • However, the diagnosis can only be made by

surgery.

• I will take questions

• Thank you!