Case Report
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Primary spinal extradural hydatid cyst causing paraplegia Sushila Jaiswal, Awadhesh Kumar Jaiswal1, Manoj Jain, Sanjay Behari1, Rakesh Pandey Departments of Pathology and 1Neurosurgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Rae Bareli Road, Lucknow - 226 014, India Address for correspondence: Dr. Sushila Jaiswal, Department of Pathology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Rae Bareli Road, Lucknow - 226 014, UP, India. E-mail:
[email protected]
ABSTRACT Spinal hydatid disease is an uncommon cause of spinal cord compression and it constitutes 1% of all cases of hydatid disease. The authors present a case of a 21-year-old female presenting with rapid onset paraplegia caused by pathologically confirmed by extradural spinal hydatid cyst. Patient had marked improvement following surgical intervention. The case is discussed and the relevant literature is briefly reviewed.
KEY WORDS: Echinococcus granulosus, extradural, hydatid disease, infectious, paraplegia, spinal DOI: 10.4103/0377-4929.55018
PMID: *****
INTRODUCTION Hydatid disease, also called cystic echinococcosis (CE) in humans is caused by tapeworm cestode, Echinococcus granulosus.[1] The disease affects the liver and lung in 80-90% of cases. Bone involvement is less common and accounts for 0.4-5% of reported cases. [2] Primary spinal hydatid cysts are extremely rare and account for about 1% of all cases of hydatid disease.[3] The authors report a histopathologically confirmed primary spinal hydatid disease in a 21-year-old lady presenting with paraplegia. The relevant literature is briefly reviewed. CASE REPORT A 21-year-old female presented to the neurosurgery clinic with the complaints of backache for one month. She also had rapidly progressive weakness of both lower limbs for two weeks and was paraplegic with sphincteric involvement for five days prior to admission. Neurological examination revealed spastic paraplegia with hypoesthesia below D12 dermatome. Her hematological and biochemical parameters were normal. Magnetic resonance imaging (MRI) of dorsal spine revealed multiple extradural heterogeneous cystic lesions with severe spinal cord compression at the D10 level [Figure 1]. Her ultrasonographic examination of the abdominal and pelvic organs did not demonstrate any disease. Laminectomy was performed at D9-D11 levels. Intraoperatively, numerous extradural cystic lesions were encountered compressing the spinal cord [Figure 2]. They had translucent walls and clear fluid content typical of hydatid cysts with destruction of the posterior elements of the D10 vertebra. All the cysts were removed from the adjacent extradural spaces. Histopathological examination showed the cyst wall having an outer acellular laminated layer and inner germinal layer characteristic of a hydatid cyst [Figure 3]. Following surgery, the bilateral lower limb weakness improved significantly 432
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and she was discharged with instructions to continue a regimen of anthelmintic treatment consisting of albendazole (400 mg twice a day). DISCUSSION Spinal hydatid cysts are uncommon and constitute about 0.5-1% of all echinococcal lesions in the body.[3] Disease usually spreads over the spine by direct extension from pulmonary, abdominal, or pelvic infestation and most commonly affects the thoracic (52%), followed by the lumbar (37%) and then the cervical and sacral spine. [4-6] Once it reaches an organ, it develops into a cystic cavity (hydatid cyst). The cyst develops slowly, takes several years to reach 5 cm in diameter in most organs. Braithwaite and Lees classified spinal hydatid disease into five types.[7] 1. Primary intramedullary hydatid disease 2. Intradural extramedullary hydatid cyst 3. Extradural intraspinal hydatid cyst 4. Hydatid disease of the vertebra 5. Paravertebral hydatid disease Our case was an example of Type 3 variety. Clinical features of spinal hydatid disease are those of slowly growing mass in the involved organ. Early symptoms appear when the small cyst expands and produces significant mechanical compression of adjacent vital structures. The cyst has an inner germinal layer which is semitransparent, white-yellowish and an outer acellular or laminated membrane recognized grossly by its ivory white color. On histology, the laminated membrane
MICROBIOLOGY - 52(3), JULY-SEPTEMBER 2009
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Figure 1: MRI dorsal spine axial section showing multiple cystic lesions causing cord compression
Figure 2: Intraoperative specimen of hydatid cysts
and are related to compression of the spinal cord leading to varying degree of weakness of limbs.[9] Our patient presented with complete paraplegia which improved significantly following surgery. On MRI, the appearance of spinal hydatid cyst is quite characteristic and it has two dome-shaped ends, has no debris in its lumen and looks like a sausage. Cyst walls are very thin and regular and have no septation.[10] Serologic findings may help in the diagnosis, but they are not reliable by themselves. Surgical excision is the mainstay of treatment and it should follow antihelmintic drugs for six months to avoid recurrence. REFERENCES 1.
Figure 3: Photomicrograph showing the cyst wall composed of eosinophilic, acellular and laminated membrane with focal formation of protoscolex
2.
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stains amphophilic with H and E stain and is positive with periodic acid-Schiff stain. The external-most fibrous or adventitial layer forms as a reaction of the host to the cyst. At a certain point, cells of the germinal layer proliferate to form a protoscolex, which has refractile hooklets and may be seen in some histological sections. Additional protoscolices grow within a vesicle of germinating membrane to form brood capsules. Brood capsules may rupture and larvae may drop into the fluid (hydatid sand). The fluid having sediment i.e. deposits, is composed of protoscolices, brood capsules, and hooklets which are refractile and stain brilliant purple with Zeihl-Nielsen stain on microscopy. Seepage of the fluid causes inflammatory reaction and or granulomatous inflammation with histiocytes and giant cells. Those brood capsules which remain attached to the germinal layer, grow and form daughter cysts, while others degenerate and calcify. All protoscolices are infective stages for the definitive hosts.[8] The symptoms of spinal hydatid disease are non-pathognomonic, INDIAN JOURNAL
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