We report a case of an unpigmented papillary carcinoma arising in a black t
hyroid induced by minocycline. Black thyroid syndrome is an unusual pigment
ed change seen almost exclusively in patients on minocycline, apparently re
sulting from an oxidative interaction between thyroid peroxidase and the dr
ug. Twenty-six cases have previously been reported in the English literatur
e, nine of which described an associated thyroid neoplasm. Four of these ni
ne neoplasms were described as pale or hypopigmented. The nature of the les
ion against the background of pigmentation suggests diminished function of
the thyroid peroxidase in this clonal population.