Sparganosis of the Cauda Equina: A Rare Case of Lower Thoracic Cord Edema and Diagnostic Challenges

Abstract

Sparganosis is a rare parasitic infection caused by the larvae of Spirometra species, with spinal involvement being exceedingly uncommon. We present the case of a 46-year-old woman with progressive lower limb weakness, sensory deficits, and bowel and bladder dysfunction over a 3-month period. Initial magnetic resonance imaging revealed an abnormal intradural lesion from L2 to S2, along with thoracic spinal cord edema, raising suspicion for a spinal dural arteriovenous fistula (DAVF). After referral to our institution, further imaging ruled out DAVF, and findings suggested arachnoiditis and radiculitis of the lumbosacral nerve roots. The patient underwent a laminectomy, revealing inflamed arachnoid membranes and diffuse yellowish-whitish granulation tissue adherent to the cauda equina, which histopathological analysis confirmed as sparganosis. Postoperatively, the patient showed improved motor strength, although bowel and bladder dysfunction persisted. This case highlights the diagnostic challenges of spinal sparganosis, the need for early surgical intervention, and the importance of considering parasitic infections in endemic regions.

Keywords: cauda equina syndrome; lumbosacral arachnoiditis; parasitic infection; sparganosis; thoracic spinal cord edema.

Fig. 1

Magnetic resonance imaging of the lumbosacral spine. Sagittal T1-weighted ( A ), gadolinium-enhanced T1-weighted ( B ), T2-weighted ( C ), and axial gadolinium-enhanced T1-weighted images at the L2–3 ( D ), L3–4 ( E ), and L4–5 ( F ) levels reveal large intradural mass-like lesions occupying the entire thecal sac from L2 to S2. These lesions show isointense T1 signals, heterogeneous hyperintense T2 signals, and diffuse heterogeneous enhancement. No distinct spinal nerve roots are identified, likely due to clumping of the cauda equina.

Fig. 2

Magnetic resonance imaging of the lower thoracic spine. Sagittal T2-weighted image ( A ) and axial T2-weighted images at the T7 ( B ), T9 ( C ), and T12 ( D ) levels demonstrate abnormal T2-hyperintense parenchymal signal changes in the lower thoracic spinal cord.

Fig. 3

( A ) Intraoperative photograph following durotomy in the prone position, showing diffuse yellowish-whitish granulation tissue and severe adhesions of the nerve roots. Hematoxylin and eosin staining; original magnification, ×200 ( B ) and ×600 ( C ). Histological examination of a surgical specimen from the lumbar area reveals parasitic tissue with three distinct layers: an outer cuticular layer, a middle granular layer, and an inner fibrillary layer. Degenerated cuticle (arrow) and calcareous bodies (arrowheads) within the parasite are visible. ( D ) Magnetic resonance imaging of the thoracolumbar spine obtained 1 year after surgery. The sagittal T2-weighted image reveals resolution of thoracic cord edema and decreased clumping of the cauda equina.