PSAT294 Black Thyroid – Is It a Benign or a Malignant Finding?: A Case Report and Review of the Literature

Abstract Background Black thyroid is a rare condition with fewer than 70 cases reported around the globe. Black thyroid is seen almost exclusively in patients upon minocycline ingestion, and the process has previously been thought to be generally benign. Despite the favorable impact of this drug on thyroid function, several studies have reported an association between black thyroid and thyroid cancer. Herein, we report a black thyroid associated with papillary thyroid cancer. Clinical Case A 30-year-old woman with no significant medical history and no risk factors for thyroid cancer, but with a history of acne treated with minocycline for 2 months 10 years ago, came to the office for a thyroid nodule found during a routine healthcare visit. The patient was asymptomatic and euthyroid. Physical examination was unremarkable. The thyroid ultrasonography showed a 1.4 × 1.0 cm hypoechogenic solid nodule with irregular borders and microcalcifications located in the right lobe. No cervical lymph nodules were found. Fine-needle aspiration of the nodule displayed a Bethesda VI category. Total thyroidectomy was performed. No lymph node dissection was implemented. During surgery, the thyroid parenchyma was diffusely black in color, increased in size, and multinodular. The patient was uneventfully discharged on postoperative day 1. Histopathology revealed a diffuse black discoloration of the specimen with a well-defined 1.2×0.8×0.6 cm nodule in the right upper lobe with features of classic papillary thyroid carcinoma. Recently the patient was seen at his 3-month follow-up, and there were no signs or symptoms of recurrence or metastasis. Clinical lessons: Although several studies describe a higher incidence of malignancy (being papillary thyroid carcinoma the most frequently associated) in black thyroid compared to non-black thyroid glands, a causal relationship has never been proven. Perhaps in this case the thyroid ultrasonography screening triggered the overdiagnosis and subsequently the overtreatment. Finally, having a "black organ" can be distressing for patients. Therefore, we should be meticulous in explaining "this disturbing fact". Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.