A distinctive but very rare side effect of exposure to minocycline is black pigmentation of the thyroid gland. Until 2002, not more than 30 cases of black thyroid had been reported in the English literature. We report on a 24-year-old woman with known antemortem ingestion of minocycline. The woman suffered from a depressive disorder with repeated suicide attempts and committed suicide by a gunshot to the head. At autopsy, the thyroid gland showed coal-black coloration. Upon histology, clumps of black-brown pigment were seen in the colloid, and a granular precipitate of this pigment was noted in the apical portions of the follicular epithelial cells. The diagnosis of minocycline-associated black thyroid was established. Forensic pathological significance of black thyroid may arise from the fact that hypothyroidism has been occasionally associated with minocycline-related black thyroid and that hypothyroidism may contribute to the development of depressive disorders (and thus, in given cases, may be responsible for suicide attempts). Under this assumption, the presence of black thyroid would represent more than just a morphological curiosity in specific cases.
