Bronchogenic Cyst of the Filum Terminale: A Case Report and Literature Review

This case report delineates the case of a 35-year-old male patient who has experienced an acute onset of difficulty initiating and evacuating his bladder, with a nine-month background history of gradually progressive low back pain. The patient also had urinary urgency. The MRI spine revealed a well-defined intradural extra-medullary non-enhancing cyst at T12-L1 that measured 1.1 x 1.3 cm and resulted in significant cord compression. There was no other cutaneous, spinal cord, or vertebral abnormality associated. The patient underwent a T12-L1 laminectomy and a gross total excision of the spinal intradural extramedullary cyst, which was observed to be firmly attached to the filum terminale. The opaque fluid was obtained by puncturing the resected cyst. There was no change in the somatosensory evoked potential during the cyst resection. The patient observed a substantial improvement in his voiding habit on the first postoperative day and was discharged two days later. The histological examination verified the diagnosis of a bronchogenic cyst (BC) by demonstrating a benign cyst surrounded by ciliated pseudostratified columnar cells, dispersed Goblet cells, and underlying fibrous tissue. This case represents an example of intraspinal BCs, which are rare intradural extramedullary lesions, most commonly in the cervical or upper thoracic spine. They are slow-growing, and their clinical presentation is variable. Surgical resection remains the primary treatment for symptomatic cases, with gross total resection (GTR) preferred due to its superior outcomes in symptomatic relief and recurrence rates. However, complete resection is often challenging due to the cyst's ventral location or adherence to critical neural structures, emphasizing the importance of electrophysiological monitoring during surgery.