AJR 2003; 180:1739-1740
© American Roentgen Ray Society
Intervertebral Disk Hydatid Cysts: MR Imaging Findings
Apostolos H. Karantanas,
Kostas Paterakis and
Antonios Karavelis
General Hospital Larissa, 411 10 Greece
University Hospital Larissa, 411 10 Greece
Spinal hydatid disease, although rare, is a manifestation of hydatid
infection. We report a case of paraspinal hydatid disease extending into two
contiguous intervertebral disks and describe the MR imaging findings. This is
the first case in the literature, to the best of our knowledge.
A 76-year-old man was admitted to the hospital because of dorsal back pain
and a gradually increasing weakness of the left leg that had lasted for 15
days. Findings of physical examination disclosed a left lower limb paresis,
absence of the left patellar reflex, and sensory loss below the right T8
level.
He had previously undergone surgery twice for hepatic hydatid disease and
for superficial soft-tissue hydatid disease in the dorsal back, not involving
the spine. The possible clinical diagnosis was Brown-Séquard's syndrome
complicating hydatid disease, and urgent MR imaging was requested. MR imaging
was performed with a 1-T scanner using a phased array spinal coil. The
T2-weighted turbo spin-echo sequences in transverse, coronal, and sagittal
planes (Figs. 2A,
2B,
2C,
2D) showed the typical cystic
multiloculated lesions located in the left paraspinal area, into the spinal
canal displacing the cord to the right, and into the intervertebral disks
T5–T6 and T6–T7. An urgent operation was scheduled. The spine was
exposed via a posterior midline T4–T6 incision. The imaging findings
were confirmed, and multiple hydatid cysts were resected. The cord was
decompressed. Postoperatively the patient had a respiratory infection and died
from respiratory failure.
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Fig. 2A. —76-year-old man who presented with dorsal back pain and
gradually increasing weakness of left leg. Axial T2-weighted turbo spin-echo
MR image at level of intervertebral disk T6–T7 shows multiple hydatid
cysts in disk and in left paraspinal soft tissues.
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Fig. 2B. —76-year-old man who presented with dorsal back pain and
gradually increasing weakness of left leg. Coronal T2-weighted turbo spin-echo
MR image shows multiple hydatid cysts at level of T5–T6 bodies located
in disk and paraspinal soft tissues.
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Fig. 2C. —76-year-old man who presented with dorsal back pain and
gradually increasing weakness of left leg. Left parasagittal (C) and
midsagittal (D) T2-weighted turbo spin-echo MR images show hydatid
cysts in disks and in anterior and posterior epidural space compressing spinal
cord.
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Fig. 2D. —76-year-old man who presented with dorsal back pain and
gradually increasing weakness of left leg. Left parasagittal (C) and
midsagittal (D) T2-weighted turbo spin-echo MR images show hydatid
cysts in disks and in anterior and posterior epidural space compressing spinal
cord.
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Primary spinal hydatid disease is rare and is often misdiagnosed as
tuberculosis [1]. Primary
spinal involvement affects the vertebral bodies as a result of portovertebral
shunts. Intervertebral disk involvement is not possible because of the low
infective potential of hydatid disease. Actually, Basak et al.
[2] suggested that the
intervertebral disks are usually preserved because the disease tends to
propagate beneath the periosteum and ligaments. In the same report, no
involvement of intervertebral disks in 12 patients was reported. Rarely, a
hydatid embryo can escape the hepatic and lung filters and enter the arterial
system, reaching almost every organ, skeleton and soft tissue included, in the
way that hydatid cysts were developed in the dorsal soft tissues of our
patient. Presumably, residual cysts from previous operations reached the
spinal canal via the intervertebral foramen and invaded the disks. A thorough
literature research disclosed two reports of contiguous vertebral body
involvement, although they did not describe live hydatid cysts in the disks
[3,
4].
Spinal hydatid disease associated with cord compression should be treated
surgically [3]. The mortality
rate however is 50%, but the operation must be performed regardless of how
long the cord has been compressed
[1].
In conclusion, spinal hydatid disease can affect the intervertebral disks,
and MR imaging provides pathognomonic findings, similar to those in other
parts of the body.
References
- Karray S, Zlitni M, Fowles JV, et. al. Vertebral hydatidosis and
paraplegia. J Bone Joint Surg Br
1990;72:84
–88[Medline]
- Basak M, Ozel A, Yildirim O, Erturk M. Relapsing hydatid disease
involving the vertebral body and paravertebral soft tissues. Acta
Radiol 2002;43:192
–193[Medline]
- Bhojraj SY, Shetty NR. Primary hydatid disease of the spine: an
unusual cause of progressive paraplegia—case report and review of the
literature. J Neurosurg
1999;91:216
–218[Medline]
- Normelli HCM, Aaro SI, Follin PH. Vertebral hydatid cyst infection
(Echinococcus granulosus): a case report. Eur Spine
J 1998;7:158
–161[Medline]
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