Spontaneous Lumbar Ligamentum Flavum Hematoma Presenting with Subacute Radiculopathy: A Case Report and Review of the Literature

Abstract Ligamentum flavum hematoma (LFH) is an exceptionally rare cause of lumbar radiculopathy and spinal canal stenosis, often leading to diagnostic uncertainty due to its nonspecific clinical and radiological presentation and its ability to mimic more common posterior extradural lesions. We report the case of a 70-year-old man presenting with progressive lumbar radiculopathy related to a posterior extradural lesion at the L3–L4 level. Magnetic resonance imaging demonstrated a well-defined nodular lesion closely related to the ligamentum flavum, initially suggestive of a synovial cyst. The patient underwent minimally invasive microscopic decompression with complete excision of the pathological ligament. Intraoperatively, a hypertrophied and remodeled ligamentum flavum containing organized hemorrhagic material was identified and removed. Histopathological examination revealed chronic inflammatory and fibrotic changes without evidence of neoplasia, confirming the diagnosis of spontaneous LFH. The postoperative course was uneventful, with rapid resolution of symptoms and full functional recovery at early follow-up. Although rare, LFH should be considered in the differential diagnosis of posterior extradural lesions, particularly in elderly patients with degenerative spinal changes, and surgical excision remains the treatment of choice, providing both definitive diagnosis and effective neural decompression with favorable clinical outcomes.