BLOG: The thyroid ‘supermoon’
For my inaugural post for this blog in November 2016, I wrote about the spectacular sight of the closest full supermoon since January 1948. It was a special occasion for me, generally and personally.
Figure 1 is a picture of a full moon on a cold, snowy night in East Lansing, Michigan. I took this picture few years ago in the parking lot of a Costco after I stopped to buy few items for my wife. As I exited the store, I glanced at the full moon. It was perfect, with its circular shape and beautiful halo around it. The size of the full moon is generally stable over the years; a so-called supermoon can occur up to three or four times a year. The closest full supermoon of the 21st century will occur on Dec. 6, 2052.
Recently, I was surprised by a very different “supermoon.”
Figure 2 shows what I will call a thyroid supermoon. It is a snapshot from a radioiodine (RAI) nuclear scan of a thyroid hot nodule (ie, toxic nodule), or an overactive thyroid nodule. This nuclear study was done for further evaluation of a case of hyperthyroidism and a large, right-side thyroid nodule in a woman aged 20 years.
The nuclear uptake of the patient’s thyroid gland was mildly elevated at 24% and 35% at 6 and 24 hours, respectively. The whole nuclear uptake is taken up by the large hot nodule. The rest of the right lobe, marked with the letter R, has no uptake, hence the circular appearance. The left lobe, marked by the letter L, had zero nuclear uptake so it appears dark, as if the lobe is completely absent. Therefore, the uptake is exclusively limited to the nodule, which appears circular in the two-dimensional view of the scan, with no uptake elsewhere in the gland. This, collectively, gave the appearance of a supermoon, especially with the halo surrounding the intense circular uptake in the nodule.
Over the years, I have seen countless RAI nuclear scans, but I have never seen such a well-rounded, moon-shaped and bright nodule with a less bright halo around it, so much resembling a supermoon in a clear sky.
I plan to publish this picture and the case history in the literature. In brief, the patient was treated with methimazole for few months, but because of the large size of the nodule and the prospect of lifelong medical therapy, it was mutually agreed to remove the toxic (hot) nodule.
The patient approved publishing her case and scan. Whenever she comes for follow-up, we both joke about her thyroid “supermoon.”
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