Monday, September 22, 2008

Thyroid biopsies

One of the things I really like at my new practice is that we have 2 ultrasound machines (One, incidentally, I've hijacked and put in my own exam room). Being the product of a modern endocrine fellowship program, my peers and I are probably a lot more adept at doing thyroid ultrasounds and performing ultrasound-guided fine-needle aspiration biopsies, compared to seniors even 5 years ahead of me. Because of an aggressive push by mentors and teachers, and a change in the syllabus of the fellowship programs, thankfully we got a lot more training in this area. I remember the times we practiced on chicken breasts, looking for the little olive hidden somewhere in the flesh. By the time my classmates and I graduated from our fellowships at WFMC, I had already done 84 thyroid biopsies.
It's not too technically difficult to do, but definitely takes practice knowing exactly where to put the probe, and where to stick the needle. I found this video on Youtube; similar to what I do, though I always use the ultrasound for guidance. The numerous publications have made it clear; the diagnostic yield improves greatly compared to palpation-guided biopsies.

It's handy being able to check out the thyroid in real time. After all, your fingers can only be so sensitive, and you can't really feel microcalcifications or appreciate the microvasculature. And if you've ever tried to read someone else's ultrasound images without real-time benefits of being able to move the probe up or down, you know how difficult it is to know exactly where you are.
It's my 6th week at my new practice, and so far I've done 14 ultrasound-guided thyroid biopsies. It's sometimes complex, deciding who you should biopsy and who you shouldn't. In younger patients with a hypoechoic, irregular nodule with microcalcifications it's a lot more obvious, but if your patient is older and has multinodular goiter with one suspicious looking goomba, but is likely not going to live for another 10 years, sometime it's a judgment call. Not mine, but the patient's. I tell them honestly; worst case scenario they have a focus of papillary thyroid cancer, but it's likely not going to kill them before their natural deaths.
The other challenge is not getting a slam-dunk 'positive for malignancy' or 'benign' report from the pathologist.
If you get a 'nondiagnostic' report (which occurs in 5-10% of cases, a limitation of the procedure) then you're back at square one. Do you rebiopsy? If so, when? Do you just monitor with U/S? Or do you consider lobectomy?
Or, the one I consider the bigger pain-in-the-ass is the 'suspicious' report. Ie, suspicious for follicular neoplasm, or something to that effect. It's a fact. The FNA is a powerful tool, but cannot distinguish a follicular neoplasm from a follicular carcinoma. The distinction is made from histology, evidence of vascular invasion. Something you just don't see with cytology. And you know that chances are, 85% of these suckers are going to be benign, but because of the 15% otherwise, you usually end up having to send a patient to the surgeon for lobectomy. I got one such case today.
Chances are, 32-year old Mrs. F will have a benign nodule. But, we won't know until the surgeon takes out a chunk of her thyroid. A minor procedure, but a surgery nonetheless, and something I wish I wouldn't have to subject my patients to unnecessarily.
But I have to say, it's pretty cool that I have a good friend here, a Malaysian pathologist, whom I'm able to call up on a whim just to discuss the cytopathology reports.


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