minocycline and Adenoma

A 22-year-old woman with a "hot" thyroid nodule who was being treated with minocycline for severe acne vulgaris is presented. A partial thyroidectomy specimen revealed a black adenoma. Microscopically, the black pigment was found in the follicular cells and the colloid of the adenoma. The pigment was bleached with potassium permanganate and was Fontana-Masson stain positive. It was negative for iron, periodic acid-Schiff, and acid-fast Ziehl-Neelsen stains. All these feature suggest a melanin-like pigment. However, electron microscopic examination revealed a dense osmophilic material present within the lysosomes of the follicular cells. No melanosomes were present. Twenty-six previously reported cases are reviewed, and the possible mechanisms for the deposition of the pigment in the adenoma and its relation to minocycline degradation products are discussed.

Topics: Acne Vulgaris; Adenoma; Adult; Anti-Bacterial Agents; Female; Histocytochemistry; Humans; Microscopy, Electron; Minocycline; Pigmentation; Thyroid Neoplasms

We report this case to further document in the literature morphologic changes encountered in a black thyroid gland. It is only through an expanding data base that future conclusions may be reached regarding the role, if any, of minocycline in some of these alterations.

Topics: Adenoma; Adult; Female; Humans; Minocycline; Pigmentation Disorders; Thyroid Function Tests; Thyroid Neoplasms

Topics: Acne Vulgaris; Adenoma; Humans; Male; Middle Aged; Minocycline; Pigmentation; Thyroid Neoplasms