Thyroid Nodules

Thyroid Nodules

·        Are common (occur in 10 – 60% depending on definition) but clinical malignancy is rare (2 – 10/100,000/year)

·        Evaluation:

o   Presents with lump in lower neck

o   Age: young with nodules more likely to be cancer

o   Gender: Females have more nodules, male‟s nodule more likely to be cancer

o   Risk factors: radiation, family history, large solitary nodule bigger risk than many small ones

o   Symptoms: 

§  Systemic: ¯weight and appetite, night sweats

§  Local: pain, stridor

o   Tests:

§  Usually normal thyroid function

§  Tumour markers: thyroglobulin, calcitonin

§  Imaging: Not specific: Cold spots – can be cancer but also normal. Hot spots unlikely to be cancer

§  US

§  FNA best

·        Benign types:

o   Haemorrhage into a thyroid cyst: painful and instantly palpable

o   Adenoma: always follicular, encapsulated, universally benign. Usually cold on scan, may be hot

·        Malignant:

o   Papillary Thyroid Cancer:

§  60% of carcinomas

§  Have papillary (finger like) architecture with fibro vascular core

§  Metastasises to lymph nodes

§  May also have calcified bits Þ Psammoma Bodies (also found in meningiomas, serous cystadenoma of the ovary)

§  Prognosis: If extra-thyroid lesions then 62% survival @ 15 years 

o   Follicular carcinoma: rarely multifocal, capsular invasion, metastasises via blood vessels. If gross invasion then 50% survival at 6 years. Hard to differentiate from adenoma on FNA

o   Anaplastic (undifferentiated carcinoma): highly malignant, old age, poor prognosis

o   Medullary/C Cell carcinoma: parafollicular cells (­serum calcitonin). Usually part of Multiple Endocrine Neoplasia Syndrome (MEN)

o   Treatment: near total thyroidectomy. If staging indicates high risk then radioiodine for remnant ablation

o   Also lymphoma

·        Multinodular Goitre:

o   With time, all thyroids have:

§  Anatomical heterogeneity: cold/fibrosed regions, hyperplasia, calcification, etc

§  Functional heterogeneity: various degrees of autonomy

o   If pronounced, then multinodular goitre:

§  Can be substantially enlarged with cystic appearance

§  Growth may ® haemorrhage ® tender

§  Treatment: Cut it out or thyroxine (slows it down)

·        In addition to a tumour, a single nodule may be:

o   A hyperplastic nodule (ie physiological)

o   Multinodular goitre with a prominent nodule

o   Thyroglossal duct cysts