Thyroid Nodule Management

[futuredoctor10]

I have seen some mixed information on management of thyroid nodules.

I tried to put it all together here. Which is correct, source 1 or source 2? Or something different altogether?

Source 1: Thyroid Nodule Workup:
1) First obtain TSH/T4 to determine if functioning or not
2) If TSH/T4 are normal, then non-functioning, so perform FNA biopsy to rule out cancer
3) If TSH/T4 are abnormal (high T4 with low TSH), then functioning:
a. RAIU scan: if hot, this is functioning and can be radioablated or medically treated
b. RAIU scan: if cold, this requires FNA

So basically when euthyroid with nodule, you have to biopsy.
When hyperthyroid with nodule, if hot on RAIU you don't biospy and if cold you do biopsy.

Source 2: Thyroid Nodule:
1) If a nodule is detected on physical exam, the next step is to obtain a FNA biopsy.
2) If biospy shows cancer/malignancy: remove. If biopsy shows benign: obs/monitor, repeat FNA later.
3) Only if the FNA biopsy is uncertain/equivocal, then you obtain the RAIU scan:
if cold you do surgery [and] if hot then you do close observation.

Both sources agree that:
-In general, avoid ultrasound [ultrasound is unreliable as cystic or solid can be malignant]
-Hot nodules are very unlikely to be cancerous, whereas cold nodules with decreased uptake may be cancer.

The sources differ in the "next best step" following nodule detection and when an RAIU scan is indicated with thyroid nodule. Please help sort this out!

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[futuredoctor10]

Also: I was wondering when will a patient with thyroid nodule and hyperthyroidism have a cold RAIU scan?

I know there are cases of hyperthyroidism with decreased RAIU uptake (e.g. thyroiditis, exogenous use/overdose, struma ovarii), but my understanding was that these usually just presented with laboratory abnormalities not with nodule.

 

[thehundredthone]

Source 1: Thyroid Nodule Workup:
1) First obtain TSH/T4 to determine if functioning or not
2) If TSH/T4 are normal, then non-functioning, so perform FNA biopsy to rule out cancer
3) If TSH/T4 are abnormal (high T4 with low TSH), then functioning:
a. RAIU scan: if hot, this is functioning and can be radioablated or medically treated
b. RAIU scan: if cold, this requires FNA

So basically when euthyroid with nodule, you have to biopsy.
When hyperthyroid with nodule, if hot on RAIU you don't biospy and if cold you do biopsy.

RAIU cannot tell you whether there is a malignancy or not. However a cold nodule in the setting of hyperthyroidism should raise your suspicion for malignancy and hence you would do FNAC.

This abstract states that cold nodules in hyperthyroid patients were more often malignant than in euthyroid patients.
http://www.ncbi.nlm.nih.gov/pubmed/963421

Source 2: Thyroid Nodule:
1) If a nodule is detected on physical exam, the next step is to obtain a FNA biopsy.
2) If biospy shows cancer/malignancy: remove. If biopsy shows benign: obs/monitor, repeat FNA later.
3) Only if the FNA biopsy is uncertain/equivocal, then you obtain the RAIU scan:
if cold you do surgery [and] if hot then you do close observation.

This doesn't make sense to me. If FNAC is already done and is equivocal/follicular, the scan cannot really sway you one way or the other, because it cannot detect malignancy.

Both sources agree that:
-In general, avoid ultrasound [ultrasound is unreliable as cystic or solid can be malignant]

Ultrasound can tell you if your seemingly solitary nodule is in fact the dominant nodule of a multi-nodular goitre though, or find the dominant nodule for FNAC. However it isn't the initial or best test.

-Hot nodules are very unlikely to be cancerous, whereas cold nodules with decreased uptake may be cancer.

The first part is correct. The second part is technically correct, but cold nodules are also only rarely malignant. It's just that cold nodules are much more common.

Here's a rough guideline that's more or less in line with current practice:
http://capitalsurgicalclinic.com/forms/ThyroidNodules.pdf

Also: I was wondering when will a patient with thyroid nodule and hyperthyroidism have a cold RAIU scan?

As per the link I posted, usually only incidentally, but in 20-25% of cases (in that series), due to coexistent malignancy.

 

[futuredoctor10]

RAIU cannot tell you whether there is a malignancy or not. However a cold nodule in the setting of hyperthyroidism should raise your suspicion for malignancy and hence you would do FNAC.

This abstract states that cold nodules in hyperthyroid patients were more often malignant than in euthyroid patients.
http://www.ncbi.nlm.nih.gov/pubmed/963421

This doesn't make sense to me. If FNAC is already done and is equivocal/follicular, the scan cannot really sway you one way or the other, because it cannot detect malignancy.


Ultrasound can tell you if your seemingly solitary nodule is in fact the dominant nodule of a multi-nodular goitre though, or find the dominant nodule for FNAC. However it isn't the initial or best test.


The first part is correct. The second part is technically correct, but cold nodules are also only rarely malignant. It's just that cold nodules are much more common.

Here's a rough guideline that's more or less in line with current practice:
http://capitalsurgicalclinic.com/forms/ThyroidNodules.pdf


As per the link I posted, usually only incidentally, but in 20-25% of cases (in that series), due to coexistent malignancy.

Wow thank you for this awesome response!