Assistant Professor / Fellowship Program Director Emory University Jonesboro, Georgia, United States
Case Diagnosis: L4-5 foraminal discal cyst
Case Description: 23-year-old male with remote history of thoracolumbar instrumentation to L3 presented with right posterolateral leg pain and great toe extension weakness. Exam notable for positive right dural tension test and imaging concerning for L4 spondylolysis. Despite physical therapy and steroid taper, he had progression of pain and new dorsiflexion weakness at one-month follow-up. MRI notable for large T2-hyperintense structure in right L4-5 foramen; contrast MRI was recommended. One month after initial MRI, contrast MRI demonstrated approximately 75% size reduction of cystic structure and patient endorsed symptomatic resolution without need for additional medication or intervention. Four months after initial presentation he demonstrated no persistent functional impairments.
Discussions: Discal cyst is a relatively newly identified cause of lumbago and lumbar radiculopathy. They are uncommon intraspinal extradural masses more prevalent in the younger, male population. In 2001 Chiba et al. characterized these cysts in order to differentiate from lumbar disc herniations and other intraspinal pathologies. Clinically, they present as unilateral single nerve root compression most commonly at L4-5 level but are thought to form acutely or as a consequence of a more stressful load. On MRI they are differentiated from disc herniations by T2-hypointense rim and T2-hyperintense cystic contents. It is a rare occurrence with limited literature pertaining to the pathology and currently unknown pathogenesis. They may represent some form of lumbar spine degeneration, but are not necessarily associated with an extensive amount.
Conclusions: While there is no consensus for management and optimal treatment method remains controversial, most reported cases describe management via surgical or other interventional procedure. We report on a case of spontaneous regression without surgical or interventional treatment in order to emphasize the importance of a conservative treatment approach.