Hypopigmentation of a papillary carcinoma arising in a black thyroid.

We report a case of an unpigmented papillary carcinoma arising in a black thyroid induced by minocycline. Black thyroid syndrome is an unusual pigmented change seen almost exclusively in patients on minocycline, apparently resulting from an oxidative interaction between thyroid peroxidase and the drug. Twenty-six cases have previously been reported in the English literature, nine of which described an associated thyroid neoplasm. Four of these nine neoplasms were described as pale or hypopigmented. The nature of the lesion against the background of pigmentation suggests diminished function of the thyroid peroxidase in this clonal population.