Lumbar foraminal and far lateral juxtafacet cyst of intraspinal origin.

BACKGROUND: Symptomatic lumbar juxtafacet cysts (JFC) arise from the facet joint and almost exclusively are located in the posterolateral spinal canal. A foraminal and far lateral JFC of intraspinal origin is an exceptional finding. We report the unique case of a lumbar intra-, trans-, and extraforaminal JFC to illustrate the rare location and unusual presentation and discuss its anatomical variants, diagnostic difficulties, and therapeutic consequences. CASE DESCRIPTION: A patient presented with a left L3 radiculopathy. Computed tomography revealed an intraspinal cystic posterolateral mass at level L3-L4, accompanied by an intra- and extraforaminal lesion compressing the upper nerve root. Based on these findings, a JFC and an additional extraforaminal disc herniation were suspected. Magnetic resonance imaging showed that the intraforaminal and extraspinal mass communicated with the intraspinal lesion and was cystic as well. The patient was treated successfully by combining an interlaminar and paraisthmic access. Microsurgery disclosed a JFC, which had a small intraspinal, panforaminal, and large extraspinal part.
CONCLUSION: An unusual case of a JFC originating intraspinally and extending through the neuroforamen to become a symptomatic extraspinal lesion with compression of the upper nerve root is reported. The patient's excellent response to operative treatment confirmed the effectiveness of the combined microsurgical approach applied. The occurrence of JFC should be kept in mind in differential diagnosis of both intra- and extraspinal and foraminal lumbar lesions.