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Clinical presentation suggests spinal neoplasm, but is it really a tumor?
A 22-year-old man with no significant medical history presented with 8 months of lower back pain and paresthesia, as well as weakness involving the bilateral lower extremities.
Upon further questioning, the patient reported concurrent urinary retention and bowel incontinence. He also demonstrated pain with the Valsalva maneuver on clinical examination. He reported no changes in gait, coordination or balance.
The patient — originally from Yemen — acknowledged frequently swimming in lakes there. He immigrated to the United States 3 years ago and had not traveled outside of the country since then.
Imaging and pathology
Initial imaging with radiographs of the lumbar spine was unrevealing, demonstrating no acute fractures, dislocation or degenerative changes.
Electrodiagnostic testing demonstrated bilateral L5-S1 radiculopathies.
Spinal cord MRI with contrast demonstrated expansile infiltrative signal abnormality with associated patchy heterogenous enhancement extending from the level of T9 down to the conus (Figure 1). These findings were highly concerning for an intramedullary spinal cord tumor, such as astrocytoma or — less likely — inflammatory or infectious transverse myelitis.
The patient underwent surgical biopsy of the intradural intramedullary spinal cord lesion.
Final surgical pathology of the spinal cord revealed densely gliotic spinal cord tissue with a granulomatous inflammatory reaction surrounding the Schistosoma mansoni ova (Figure 2).
Source: M. Ghesani, MD reprinted with permission.
Focal perivascular lymphohistiocytic infiltrates were present. The atypical appearance of nuclei of the reactive astrocytes and the densely fibrillar astrogliosis present in the material evaluated intraoperatively mimicked an infiltrative astrocytoma, though upon re-evaluation of the entire case, this astrocytic process was favored to be reactive in nature.
Schistosoma IgG serum antibody was strongly positive.
The patient received one dose of praziquantel 50 mg/kg, with a plan for an additional follow-up dose 2 weeks later, and prednisone 1 mg/kg once daily for 2 months. He made a good — albeit gradual — recovery, reporting improved strength within 1 week of treatment.
Discussion
Involvement of the central nervous system by Schistosoma mansoni (ie, neuroschistosomiasis) remains underdiagnosed, particularly in nonendemic regions, given the nonspecific clinical manifestations and various potential symptomatology at presentation.
Accurate diagnosis allows early treatment, which is critical for reducing long-term morbidity and improving prognosis.
A limited number of case reports document schistosomiasis involving the spinal cord in countries where the disease is not endemic.
Here, we describe a patient in the United States who developed urinary retention and bowel incontinence as a result of neuroschistosomiasis mansoni (NSM), thought initially to represent a spinal cord astrocytoma.
Schistosoma mansoni is a helminthic infection endemic to tropical areas, affecting nearly 110 million people worldwide.
It is believed that the schistosomal larva infect the definitive human host percutaneously after emerging from the snail, entering the lymphatics and blood circulation and subsequently traveling through retrograde venous flow from the portal system to the epidural Batson’s venous plexus to reach the spinal cord and cerebral veins.
A necrotizing granulomatous reaction occurs once antigenic and immunogenic excretions are produced by the mature embryo in the early phase of disease, damaging nerve tissue and producing mass effect. The chronic phase of disease is thought to become more localized and less severe due to immunologic modulation.
The reported prevalence of NSM is low, and it likely goes underdiagnosed in endemic regions given the variability in neurological manifestations. However, it can be one of the most severe and debilitating presentations of schistosomal disease.
The most common presenting clinical symptom is myelopathy. In fact, case reports have described patients who presented with signs and symptoms of cord compression at the lower thoracic and lumbar vertebrae, such as lumbar pain, progressive myeloradiculopathy with weakness of the lower extremities, autonomic dysfunction — particularly bladder and urinary dysfunction — and severe conus medullaris and cauda equine syndrome.
In the scientific literature, data on classic imaging features of pathologically confirmed spinal NSM is scarce and primarily involves case reports. Although MRI is abnormal in most cases of NSM, findings often are nonspecific.
A diagnosis of neoplastic lesion, inflammatory or infectious transverse myelitis with cord compression based on neuroimaging findings often is made.
The expansile, infiltrative nature and heterogeneous enhancement pattern of NSM tends to mimic spinal cord astrocytoma. Frequent ancillary findings include diffuse enlargement of the lower spinal cord, isointensity and thickening of the cauda equina nerve roots on T1 with associated hyperintense signal intensity on T2.
Several enhancement patterns have been described, including heterogeneous, multinodular and patchy intramedullary contrast enhancement. Abnormal contrast enhancement also can be seen in the thickened cauda equina nerve roots. There is often cord compression, typically in the conus medullaris and the lower thoracic cord, such as in our patient.
Although differentiating neoplastic processes from NSM on the basis of MRI findings can be challenging, lack of solid or cystic contours typically seen in spinal cord neoplasms — such as ependymoma and astrocytoma — coupled with swelling of the spinal cord and patchy, multinodular intramedullary enhancement should raise suspicion for NSM and warrants further workup with cerebrospinal fluid analysis and noninvasive serologic testing.
Cerebrospinal fluid analysis may be nonspecific for NSM, demonstrating eosinophilia, lymphocytosis and elevated immunoglobulin; serology may serve as an additional tool to ensure correct diagnosis.
Some case reports have demonstrated immune markers, including interleukin-13 and anti-Sm antibodies to be specific for NSM in the appropriate clinical setting. Although the gold standard for NSM diagnosis remains spinal cord biopsy demonstrating Schistosoma eggs and reactive granulomas, effective management for NSM is possible without surgical intervention.
Early treatment with praziquantel associated with steroids prevents further egg deposition in the spinal cord, halting granuloma formation and helping to improve long-term patient outcomes.
Conclusion
NSM likely will become more common, not only in endemic areas but also in the United States and Europe due to increasing international travel, as well as refugee and population migration.
Early diagnosis and treatment are critical to avoid the debilitating symptoms of spinal cord pathology and may spare many patients suspected to have a spinal cord neoplasm from the morbidity of spinal cord surgery.
MRI that demonstrates characteristic pattern of signal intensity with associated patchy, heterogeneously enhancing lesions in the lower thoracic cord and conus medullaris among patients with an exposure history or recent travel should raise suspicion for neuroschistosomal infection and warrant further serologic workup.
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For more information:
Munir Ghesani, MD, FACNM, is assistant professor of radiology and director of PET/CT fellowship at NYU Langone Medical Center in New York. He also is a HemOnc Today Editorial Board Member. He can be reached at munir.ghesani@nyumc.org.
Ana M. Franceschi, MD, is a neuroradiology fellow at NYU Langone Medical Center.
Juhi Purswani is a medical student at New York University School of Medicine.
Disclosures: Ghesani, Franceschi and Purswani report no relevant financial disclosures.