Minocycline-induced black bone disease with synovial pigmentation in a patient undergoing revision anterior cruciate ligament surgery: A case report

INTRODUCTION: Long-term use of minocycline at high doses is associated with hyperpigmentation with multiple sites of involvement. While the cutaneous organs and the oral cavity are most commonly affected, bone discoloration is a rare entity. CASE PRESENTATION: A 19-year-old male patient with a history of acne vulgaris and intermittent treatment with high dose minocycline for three years presented with recurrent anterior cruciate ligament (ACL) tear. During arthroscopic surgery, however, hyperpigmentation of the femur and synovium was observed. Abnormal tissue was biopsied and confirmed through histopathological examination to contain melanin-related minocycline pigmentation. Revision surgery was re-scheduled with no intraoperative complications and excellent long-term clinical outcomes. CLINICAL DISCUSSION: There are several possible causes of hyperpigmentation, including hemosiderin deposition, infection, aseptic necrosis, demineralization, and metastatic disease. Black bone disease, caused by minocycline-induced hyperpigmentation, is rare. While the appearance is grossly abnormal in black bone disease, there has been no evidence suggesting that tissue integrity is compromised. CONCLUSION: This case confirms that hyperpigmentation does not affect bone integrity and that surgical procedures can be performed safely. Knowing the adverse effects of minocycline administration could reduce inappropriate postponement of surgical procedures, thereby saving time and resources.