Rapid, symptomatic enlargement of a lumbar juxtafacet cyst: case report.

Study Design: A case is reported in which a 45-year-old man developed cauda equina syndrome caused by enlargement of an L4-L5 juxtafacet cyst diagnosed 4 months earlier.

Objectives: To highlight the short interval that can elapse between the discovery of a juxtafacet cyst and its remarkable progression.

Summary Of Background Data: Although juxtafacet cysts are acquired lesions, how long they take to develop remains unclear. Hemorrhage is a well-known cause of rapid or even dramatic cyst enlargement. This is the first report providing magnetic resonance imaging evidence of rapid, remarkable enlargement of a nonhemorrhagic juxtafacet cyst.

Methods: The patient underwent conservative treatment for an L4-L5 right juxtafacet cyst diagnosed by magnetic resonance imaging during evaluation of posttraumatic lower back pain. Four months later, the patient presented with severe pain radiating down the right lateral leg, urinary retention, and impaired dorsal flexion of the right foot. Repeat magnetic resonance imaging showed the cyst now markedly enlarged and occupying almost the entire width of the canal.

Results: The cyst was removed, and the patient's symptoms abated. At 15 months after surgery, he is symptom-free.

Conclusions: Juxtafacet cyst may occasionally enlarge and cause severe symptoms within months.