Fine needle aspiration cytologic findings in the black thyroid syndrome

The cytologic presentation of a case of minocycline-associated black thyroid adenoma in a 30-year-old woman is described. A nodule was discovered in the left lobe of the patient's thyroid gland, and fine needle aspiration (FNA) was performed; the nodule and adjacent thyroid were subsequently surgically removed. The cytologic findings included sparse groups of epithelial cells with prominent intracytoplasmic pigment granules. The surgical specimen was interpreted as black thyroid adenoma. This case is unusual in that the pigment had accumulated preferentially in the adenoma. In retrospect, the finding of distinctive pigment in the aspirate of the nodule suggests that the black thyroid syndrome should be considered whenever dark-brown pigment is encountered in FNA cytologic specimens from the thyroid gland.