Surgical Management of a Case of Amyloidosis-Associated Ligamentum Flavum Hypertrophy in a 37-Year-Old Indian Male

Abstract

Amyloidosis is a rare systemic disorder characterised by extracellular deposition of insoluble protein fibrils, most commonly involving the heart. However, amyloid deposition can also occur in other tissues, often asymptomatically. The ligamentum flavum (LF) is one such site where the amyloid may accumulate, potentially contributing to spinal canal stenosis. We report the case of a 37-year-old Indian male who presented with a 7-month history of chronic mid-to-lower back pain. Radiographs showed normal spinal alignment, while magnetic resonance imaging revealed mild disc degeneration and hypertrophy of the LF from T-10 to L-1, consistent with thoracolumbar canal stenosis. Electrocardiography revealed QRS abnormalities, and echocardiography demonstrated diastolic dysfunction with mild left ventricular hypertrophy. Laboratory investigations were largely unremarkable, except for elevated blood glucose and impaired renal function. Urine electrophoresis indicated the presence of monoclonal proteins. The patient underwent laminectomy and decompression, and the excised LF tissue was submitted for histopathological evaluation. Congo red staining confirmed amyloid deposition, and further analysis identified the transthyretin (ATTR) subtype. Genetic testing revealed wild-type ATTR (ATTRwt) amyloidosis. Postoperatively, the patient made an uneventful recovery over 6 months, with continued orthopaedic and multidisciplinary follow-up. This case underscores the significance of considering amyloidosis, particularly ATTRwt, as a differential diagnosis in patients presenting with LF hypertrophy and spinal stenosis, especially when accompanied by systemic findings.