Multinodular goitre (MNG) is defined as an enlarged thyroid gland (i.e. goitre) due to multiple nodules which may have normal, decreased or increased (toxic nodule) function. It is a slightly unhelpful term as some multinodular thyroids are not enlarged, resulting in the unwieldy term "multinodular non-enlarged thyroid".
MNG is seen more commonly in females (M:F=1:3) in the 35-50 years age range, who present with nodular enlargement in the midline of the neck. Patients are usually euthyroid, but the nodules may also be hypo- or hyperfunctioning, resulting in systemic symptoms from hypothyroidism or hyperthyroidism.
MNG develop from simple goitres as a result of repeated instances of stimulation and involution 4.
Most of the nodules are hyperplastic or adenomatous with varying degree of cystic/liquefactive degeneration. Presence of serous/colloid fluid may be noted.
A nodule in MNG may harbour malignancy. Family history of malignancy and prior neck radiation exposure are known risk factors 2.
Sonography remains the first radiological investigation to screen the nodules and look for any suspicion of malignant change in the nodules which is not uncommon.
Usually the benign nodules in MNGs show the following features:
- surrounding hypoechoic halo
- spongelike/honeycomb pattern
- peripheral (eggshell) or coarse calcifications
- Doppler: peripheral vessels are usually noted, may show intranodular vascularity (mostly in hyperfunctioning nodules)
It is important to screen for presence of malignant features (if any) in any of the nodules and subsequent FNA can be done from the suspicious nodule.
Malignant sonographic features
- hypoechoic solid
- intranodular blood flow
- large size: the cut off is often taken as 10 mm to warrant a FNA
- presence of microcalcifications: almost always warrants a FNA
Benign sonographic features
- large cystic component
- hyperechoic solid
- comet tail artifact
See main article assessment of thyroid lesions for further details.
- Tc-99m pertechnetate or radioiodine (I123) demonstrate an enlarged gland, with heterogeneous uptake
- thyroid uptake and scan determines the activity of the gland
- goitre is on the differential for an anterior/superior mediastinal mass, and is associated with the cervicothoracic sign
- associated with deviation of the trachea
- not a primary modality for diagnosis, but may be seen incidentally
- CT may be useful for fully characterizing the extent of substernal goitre
- an enlarged and heterogeneous thyroid gland suggests the diagnosis, which is confirmed with ultrasound or scintigraphy
Treatment and prognosis
Treatment of multinodular goitre may be pursued if the thyroid is hyperfunctioning, or if the goitre is causing local mass effect. There is no standard treatment and choice of treatment depends on local practice patterns, the activity of the goitre, and the results of FNA of any suspicious nodules.
- surgery: partial or complete resection
- radioiodine: occasionally used
- dose = (thyroid weight x planned radioiodine delivery to thyroid) / radioiodine uptake
- hypothyroidism may occur as an adverse event
Conservative management is also an option as some goitres decrease their rate of growth or may even decrease in size 6.
- patients with MNG are at increased risk of iodinated contrast-induced thyrotoxicosis (although this is rare in itself) 5
- 1. Bahn RS, Castro MR. Approach to the patient with nontoxic multinodular goiter. J. Clin. Endocrinol. Metab. 2011;96 (5): 1202-12. doi:10.1210/jc.2010-2583 - Pubmed citation
- 2. Ríos A, Rodríguez JM, Canteras M et-al. Risk factors for malignancy in multinodular goitres. Eur J Surg Oncol. 2004;30 (1): 58-62. Pubmed citation
- 3. Hurley DL, Gharib H. Evaluation and management of multinodular goiter. Otolaryngol. Clin. North Am. 1996;29 (4): 527-40. Pubmed citation
- 4. Mitchell R, Kumar V, Fausto N et-al. Pocket Companion to Robbins & Cotran Pathologic Basis of Disease. Saunders. ISBN:1416054545. Read it at Google Books - Find it at Amazon
- 5. Andreucci M, Solomon R, Tasanarong A. Side effects of radiographic contrast media: pathogenesis, risk factors, and prevention. Biomed Res Int. 2014;2014: 741018. doi:10.1155/2014/741018 - Free text at pubmed - Pubmed citation
- 6. Vanderpump MP, Tunbridge WM, French JM et-al. The incidence of thyroid disorders in the community: a twenty-year follow-up of the Whickham Survey. Clin. Endocrinol. (Oxf). 1995;43 (1): 55-68. Pubmed citation
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