Neglected alkaptonuric patient presented with low back pain and radiculopathy: A case report

BACKGROUND: Alkaptonuria (AKU) is a rare hereditary disorder in which excess homogentisic acid (HGA) deposits in connective tissues (ochronosis). Here, we report the unusual presentation of a lumbar disc herniation occurring in a patient with AKU warranting surgical intervention. CASE DESCRIPTION: A 28-year-old male presented with 1 year of low back pain. The lumbar magnetic resonance imaging showed an extruded disc at the L4-L5 level accompanied extensive disc space narrowing and osteophyte formation. At surgery, the interspinous ligaments, facet joints, and disc herniation were black. In addition, the postoperative re-examination revealed a black discoloration of the nasal and ear cartilage. Finally, the diagnosis of AKU was confirmed when the urine specimen was positive for HGA. CONCLUSION: Rarely, younger patients with AKU who develop excess black deposits of HGA in connective tissues (i.e., ochronosis) may present with lumbar disc herniations and spondylosis.