Introduction

Hydatid cyst disease in human also known as cystic echinococcosis (CE) is well described through history[1-3]. CE is a zoonosis usually caused by the larval stageof the tapeworm Echinococcusgranulosus. Domestic dogs and other canine are the definitive host, while man can replace the usual intermediate host, the sheep, goat and cattle[3,4]. The ova are shed in the feces of the host animal and ingested by the intermediate host. After the intestinal passage, they develop into the larva stage and eventually enter the portal vein circulation and get trapped.The predominant sites for the infestation in human are liver (up to 70%) and lungs (up to 20%) where cysts are formed. However, any part of the body can be affected[5].The tapeworm is widespread, most common in tempered zones where sheep are raised, mainly South America, Middle East, Southeast Asia, China,north and east Africa, Russia and the Mediterranean areas which include Greece and the former Yugoslavia[1,4,5]. The aim of this article is to report a case of disseminatedCE mimicking spinal malignancy in which correct diagnosis was delayed several years.

Case Presentation

A 64-years-old male native from the rural countryside of the Balkans. When he was in his 20s, he was operated at a local hospital in the former Yugoslavia for lumbar radiculopathy and an acquireddrop-foot. The right sided drop-foot persisted after surgery. He immigrated to Denmark in the early 1990s.In 2013, at the age of 60 years,he sustained a minor fall. Severe backpain andradicular pain in both legs progressed rapidly over a few days. An MRI revealed spondylodiscitis L4-L5 with abscess in the vertebral bodies and in the surrounding soft tissue (Figure 1).

A slight elevation ofC-Reactive Protein (CRP) level and eosinophil leucocyte count were the only biochemical markers of infection, and he presented no other clinical signs of an ongoing infection. L3-L5 Corpectomy and L1-S1 spondylodesis was performedfor major destructive processes. Surprisingly, the intraoperative biopsies were found negative for both malignancy and infection including TB and mycosis.

After being asymptomaticfor two years he experienced a relapse oflow back pain andradicular pain. A rapid progressinggait impairment with major paresis of the right leg developed to an extend that he had to manually aid limb motion. His general conditionwas rapidly deteriorating. The physical examination also revealed a large fluctuating migrating humpat the surgical site(Figure 2).

Laboratory blood analysis were largely normal, again except for slight elevationsof CRP level and eosinophil leucocyte count. Repeated MRI and a PET-CT was conducted, showing multiple cystic tumors in the area of the lumbar spine. The cystic tumors had increased in both size and numbers and spread to lung, liver, retro-peritoneum and the abdominal cavity (Figure 3).Especially the tissue surrounding the abdominal aorta was affected, causingan aortic aneurism. Open biopsy in the lumbar region on suspicion of malignancy or infection was again found to be negative. On suspicion of CE, serologic analysis confirmed Echinococcusgranulosus helminth infestation.

Anthelmintic albendazole treatment was instituted and by combined anterior and posterior approacha secondary surgery aimed at removing hydatid cysts surrounding the lumbar spine and to prevent further progression of lowerlimbsymptoms was performedFigures 4,5. Albendazole treatment was continued (perhaps life-long treatment) and Praziquantel was added to the anthelmintic chemotherapy for one year.Despite preventive measures, the patient experienced severe complications during the first months that followed: pulmonary embolism and cardiac arrest but he was successfully resuscitated without sequelae. Later, his aortic aneurism ruptured which caused intestinal ischemia requiring resection and ileostomy. Two-and-a-half yearsafter CE diagnosis and institution of anthelminthic treatmentthe disease remained stable.

Discussion

CE is uncommon in Scandinavia and diagnosed cases usually originates from high-incidence countries. Skeletal involvement including spinal CE is rare (0.5-4% of CE cases)[1,2].Spinal CE can be classified into 5 radiological types⁠ (Dew/Braithwaite & Leesclassification[6]): intramedullary, intradural, extradural, cyst of the vertebra and paravertebral lesion[6]. This case of spinal CE is classified as a combination of the later three subtypes and was aggravated by concurrent cysts to lung and liver. CE can be fatal,Belhasan-Garcia, et al. followed 567 mixed CE patients in Spain and found 11 deaths directly related CE[7]. Spinal CEwith paraplegia can be a truly lethal disease: Karray, et al. reported a mortality of 6 out of 13 patients (46%) but other reported mortality rates ranging from 14-56%in direct relation to CE[8] and Mills et al reported an average survival length of 5 years after onset of paraplegia in spinal CE[2]. Combined radical surgery and anthelminthic systemic drug treatment with benzimidazole compounds (albendazole for osseous involvement) is the recognized standard[9-11]. Applying intra-operative local chemotherapyseems logical, but the agent has to be left in contact with the cyst for at least 15 minutes to be effective[11]which may prove difficult in some cases.Risk-effectiveness assessments have deemed formalin obsolete for that purpose, but 90% ethanol, 20% hypertonic saline or 0.5% cetrimide solution can be used. PAIR procedure can be applied as an alternative: first ultrasound guided percutaneous puncture and aspiration from the cyst, then injection of a protoscolicidal compound (e.g. 90% ethanol or 20% hypertonic saline) for a minimum duration of 15 minutes followed by re-aspiration[11]. Complete cyst excision is often difficult in the spine due toinvasiveness and risk of cyst rupture. Cyst rupture can cause spreading of the disease, recurrence and risk of an anaphylactic reaction[9]. In this case radical excision of all the paravertebral cysts was impossible. We applied no local anthelmintic treatment, but a successful spinal canal decompression was archived together with improved mobility, reduced radiculopathy and improved general health status post-op and in follow-up.After the surgery the patient regained ambulation and the radicular symptoms were reduced.

Conclusion

This case is a rare presentation of hydatid disease or cystic echinococcosis in which correct diagnosis was delayed for several years. Parasite-infections can be the cause of severe disease patterns even in non-endemic areas.This case report highlights the importance of anamnestic exposures in immigrants and travelers alike. An increased suspicion must be raised when the histopathological and microbiological findings are not in accordance with the clinical presentationand the general condition of the patient. Appropriate paraclinical tests(e.g. specific Ig or PCR analysis) should be performed on suspicion to obtain correct diagnosis to ensure timely diagnosis and proper treatment.

Disclosures: No conflicts of interest

Figure 1: Pre-operative MRI of the sagittal plane (left) and axial plane (right) of the lumbar region showing destruction of the L4 vertebra.

Figure 2: Clinical presentation of the large migrating fluctuating hump before the second operation.

Figure 3: Repeated MRI before open biopsy and second surgery, sagittal plane (left) and axial plane (right), and a serpentine structure (arrow) inside a cyst presumably representing a collapsed cyst membrane.

Figure 4: Intraoperative images of posterior procedure for instrumented stabilization of the spine and cyst removal (left). Excised hydatid cyst cut open (right), presenting a serpentine-like structure (arrow).

Figure 5: Radiographic status of instrumentation after the second surgery, in sagittal plane (left) and frontal plane (right).

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