Thyroid Ultrasound Criteria to Diagnose Possible Malignant Tumors

There are so many important articles that do not get published in the radiology literature.

The recent issue of JAMA Internal Medicine has an article by Smith-Bindman R et al that discusses how to use thyroid USG signs to decide which nodules need to be biopsied.

Three criteria are important – microcalcifications, completely solid appearance and size greater than 2 cm. If we stringently follow the rule that at least two of these criteria have to be present before performing thyroid nodule biopsy, then the sensitivity would be reduced but with a high positive predictive value, but without compromising the ability to pick up malignancy. It is worth reading the article to understand the importance of large population based studies to help us use our radiology signs to better triage patients.

 

Sub-centimeter Lung Nodule Biopsies

This article from the November issue of the American Journal of Roentgenology discusses the results of 305 CT guided core biopsies / aspirations of small lung nodules, less than 1.0 cm in diameter, over 13 years.

The only major variable that decided success was aspiration instead of core biopsy.

I have been very clear about doing core biopsies for lesions in the body as against FNAC / aspiration for many years now. Tissue today is needed for so much more than just establishing a diagnosis that if we are going to put a needle in the lungs, or other parts of the body, it would be a travesty to come away with only cells, without tissue.

Here is an example of a 7.5 mm lung nodule biopsied earlier this year that turned out to be tuberculosis on histopathology.

Biopsy of 7.5 mm lung nodule

Biopsy of 7.5 mm lung nodule

How Fast is a Fast Response

This is a 29-years old lady who has a 4-months old child. A month after her pregnancy, she started getting some backache and chest pain and was feeling lethargic. She saw her family physician, who attributed all her symptoms and signs to post-pregnancy related issues and put her on standard symptomatic treatment, including vitamin D3 and B12 supplementation.

She did not improve and went to another family physician, who did not take her seriously as well and so she changed to a third family physician.

This last physician was concerned. She had been having fever and basic tests showed a raised ESR. According to him, she “did not look well”. He ordered a Mantoux and a CT scan of the chest both at the same time.

Her CT scan done on Mar 15, 2013, showed enlarged necrotic mediastinal nodes (Fig. 1), pericardial effusion and thickening (Figs. 1,2) and pleural effusions bilaterally (Figs. 2, 3).

Axial contrast-enhanced CT scan shows enlarged necrotic subcarinal and right hilar lymph nodes (red arrows) and pericardial effusion (blue arrow)

Axial contrast-enhanced CT scan shows enlarged necrotic subcarinal and right hilar lymph nodes (red arrows) and pericardial effusion (blue arrow)

Axial contrast-enhanced CT scan shows pericardial effusion (blue arrow) with thickening with left pleural effusion (white arrow)

Axial contrast-enhanced CT scan shows pericardial effusion (blue arrow) with thickening with left pleural effusion (white arrow)

Axial contrast-enhanced CT scan shows bilateral pleural effusions (white arrows)

Axial contrast-enhanced CT scan shows bilateral pleural effusions (white arrows)

She was asked to see a chest physician immediately. Her family came to see me and I advised the same.

In the mean time her Mantoux came strongly positive.

The chest physician started her immediately on first-line anti-tuberculous therapy with steroids for the pericardial effusion. Given the high incidence of primary multi-drug resistant tuberculosis in our country, he cautioned them that in case she did not improve clinically, she would need a CT guided subcarinal node biopsy and she was asked to see me again if that situation were to arise. There was no way to confirm the diagnosis at this time. The pleural fluid was too little and was unlikely to yield any results.

The next day, they called me and insisted on getting the biopsy done. Their reasoning was logical – they wanted to confirm the diagnosis and get material for culture and be sure that she was sensitive to first-line drugs. It is rare to find patients and families with such sensibilities.

I checked with the chest physician who agreed. If a patient wants a biopsy for confirmation, that is a request to be respected.

I posted her for a biopsy on 22 Mar, 2013. After standard counseling and explanations, I positioned her in the prone position to perform an extrapleural, CT guided subcarinal node biopsy. Lo and behold! The preliminary scans showed that the node had mildly regressed in size, the pleural effusions had regressed and the pericardial effusion had partly regressed.

I immediately called in the relatives and had the patient turn over and sit up. I explained to them that the partial regression meant response to treatment and that it made no sense to perform the biopsy at this point in time. They too agreed…they were so happy and relieved…these are the times when it is so gratifying to be a physician advising a patient. I repeated another contrast enhanced CT to document these findings (Figs. 4-6).

Axial contrast enhanced CT scans of 15 Mar and 22 Mar show partial regression of the subcarinal node.

Axial contrast enhanced CT scans of 15 Mar and 22 Mar show partial regression of the subcarinal node.

Axial contrast enhanced CT scans of 15 Mar and 22 Mar show partial regression of the pericardial effusion.

Axial contrast enhanced CT scans of 15 Mar and 22 Mar show partial regression of the pericardial effusion.

Axial contrast enhanced CT scans of 15 Mar and 22 Mar show complete regression of the pleural effusions.

Axial contrast enhanced CT scans of 15 Mar and 22 Mar show complete regression of the pleural effusions.

This is one of the fastest and quickest responses to tuberculosis that I have encountered.

Update 1:

A query on Facebook where I had posted this article asked whether there is an increased incidence of tuberculosis in the post-partum period. There is and this Pubmed link has the data.

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