Questions about the paper ‘Papillary thyroid cancer in black thyroid: a case report and literature review’

We read the review by Kim et al. titled “Papillary thyroid cancer in black thyroid: a case report and literature review” (1) with great interest. This article reports on minocycline-induced black thyroid with lymph node metastasis and provides a valuable review of the literature. The importance of follow-up for patients with a long history of minocycline ingestion is emphasized.

We agree with most of the opinions in this review, but there are still a few questions that need to be answered.

Firstly, in the introduction section, it says “pigmentation can occur more frequently in patients who have taken minocycline for more than one year at cumulative doses of >100 g”. My question is whether supplementary material can be provided to prove this point. In fact, to our knowledge, no credible studies have unfolded regarding minocycline intake and timing with black thyroid. It is thus inappropriate to present in such an absolute way.

The second question concerns with the conclusion section, in which it says “In our case, black discoloration was also seemingly observed in the surrounding adipose tissue of the neck level IV. Pathologic examination identified brown pigmentation in the thyroid parenchyma, but not in the thyroid tumor, LNs, or surrounding adipose tissues”. The conclusion on “black discoloration in the surrounding adipose tissue” is ambiguous. Can the authors describe the surrounding adipose tissue of the neck level IV in detail, or provide the microscopic photos of the surrounding adipose tissue of it?

Supplementary

The article’s supplementary files as

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.