Sparganosis in the lumbar spine : report of two cases and review of the literature

Abstract

Sparganosis is a rare parasitic infection affecting various organs, including the central nervous system, especially the lumbar epidural space. This report describes the identification of disease and different strategies of treatments with preoperative information. A 42-year-old man presented with a 2-year history of urinary incontinence and impotence. He had a history of ingesting raw frogs 40 years ago. Magnetic resonance (MR) imaging showed an intramedullary nodular mass at conus medullaris and severe inflammation in the cauda equina. A 51-year-old woman was admitted with acute pain in the left inguinal area. We observed a lesion which seemed to be a tumor of the lumbar epidural space on MR imaging. She also had a history of ingesting inadequately cooked snakes 10 years ago. In the first patient, mass removal was attempted through laminectomy and parasite infection was identified during intra-operative frozen biopsy. Total removal could not be performed because of severe arachnoiditis and adhesion. We therefore decided to terminate the operation and final histology confirmed dead sparganum infection. We also concluded further surgical trial for total removal of the dead worm and inflammatory grannulation totally. However, after seeing another physician at different hospital, he was operated again which resulted in worsening of pain and neurological deficit. In the second patient, we totally removed dorsal epidural mass. Final histology and enzyme-linked immunosorbent assay (ELISA) confirmed living sparganum infection and her pain disappeared. Although the treatment of choice is surgical resection of living sparganum with inflammation, the attempt to remove dead worm and adhesive granulation tissue may cause unwanted complications to the patients. Therefore, the result of preoperative ELISA, as well as the information from image and history, must be considered as important factors to decide whether a surgery is necessary or not.

Keywords: Enzyme-linked immunosorbent assay; Sparganosis; Sparganosis in the lumbar vertebrae.

Fig. 1

The preoperative MRI of case 1. T2-weighted magnetic resonance (MR) image shows a nodular-shaped mass (15×10 mm) in the conus medullaris and severe inflammation and adhesion of the cauda equina.

Fig. 2

The histologic finding of case 1. Low powered view shows parasite impaction (arrow) in fibroadipose tissue with granulation tissue. The body of the parasite has been degenerated and calcareous bodies are not readily discerned, but the outer layer of tegument is preserved. These finding indicate dead worm.

Fig. 3

The preoperative MRI of case 2. A : T1-weighted magnetic resonance (MR) image shows an elongated high- or iso-intensity signal mass compressing the thecal sac at the L3-4 dorsal side. B : MRI with gadolinium enhancement shows that a highly enhanced dorsal side mass is compressing thecal sac and this mass seems to be in the epidural space.

Fig. 4

Operative image of case 2. A : After laminectomy at L3 and L4, an elongated and dark reddish granulation tissue with sparganum is seen. B : Adhesion of the granulation tissue and dura was not so severe that it could be easily detached.

Fig. 5

The histologic finding of case 2. A : Low powered view shows parasite impaction (arrow) in fibroadipose tissue with granulation tissue. B : In the high powered microscopic view of the parasite, Tegument (arrowhead) covers the outer layer and many calcareous bodies (arrows) are seen inside the body of the parasite. Fragmented smooth muscles (triangles) are also observed.