Age / Sex : 43 / M

Chief complaint: radiating pain to right lower extremity

1) What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

(Quiz는 quiz일 뿐이오니 답안은 한개만 보내주시기 바라오며, 복수의 답안을 보내주시는 분은 정답이 포함되어 있더라도 부득이 semi-correct answer로 처리토록 하겠습니다.)

Courtesy: 임현경(Lim Hyun Kyong), 보라매병원(SMG-SNU Borame Medical Center)
 

PLL (posterior longitudinal ligament) cyst

Discussion

Findings:

MR images
show an ovoid cystic lesion in the right anterior epidural space between the
posterior surface of the L4 upper vertebral body and the posterior longitudinal
ligament. The cyst lies ventrally within the right lateral recess, resulting in
compression of the dural sac and the 4th right nerve root. The L3-L4, L4-L5
discs have degenerative change, but they have no communication with the cyst. There
is no communication with the facet or ligamentum flavum.

Differential Diagnosis:

intraspinal
extradural cysts including arachnoid cyst, perineural cyst, or discal cyst

Diagnosis:
 

PLL (posterior
longitudinal ligament) cyst

Discussion:

Mechanisms
for the development

1.
repetitive trauma (ß mainly reported in young, athletic
men with repetitive injury)

2. the
loading exerted by degenerated intervertebral disc on the PLL

3. facet
arthrosis, spondylolisthesis, myxomatous degeneration of the connective tissue,
increased hyaluronidase production and accumulation of viscous myxoid material

Content

- serous /
mucinous, jelly-like and hemorrhagic components + hemosiderin, blood, even air

Image
findings

- common location : left or right
anterior epidural space at the posterior surface of L5 or L4

-
MRI : T1 low / T2 homogeneous high SI / peripheral enhancement of the cyst

- CT: round mass with low density
compared with the adjacent disc

Differential
Diagnosis:

- intraspinal
extradural cysts including facet joint cyst, ligamentum flavum cyst, arachnoid
cyst, perineural cyst, or discal cyst

- extruded
or sequestered disc fragment

- neurofibroma
with cystic degeneration

Management

- spontaneous regression is rare.

- intervention : CT or endoscopy
guided needle aspiration

- surgical treatment

References:

1. Le Breton
C, Garreau de Luobresse C, Awky J, et al. (2000) L5 radicular pain related to a
cystic lesion of the posterior longitudinal ligament. Eur Radiol,
10(11):1812-1814.

2. Mizutamari
M, Sei A, Fujimoto T, Taniwaki T, Mizuta H (2009) L5 radiculopathy caused by a
ganglion cyst of the posterior longitudinal ligament in a teenager. Spine J,
9(4):e11-14.