Free-living sparganosis in the lumbosacral spine with long latency

A 36-year-old female from Jiangxi province of China was admitted to our hospital with a 3-month history of back pain radiating to the lower extremities. Physical examination revealed limitation of bending and a positive straight leg raising test. Spinal CT and MRI showed an intraspinal mass lesion located within the L4 to S1 segment. Additionally, she recalled ingesting inadequately cooked frogs 20 years ago, which was considered a traditional remedy for furuncles. No skin nodules or organomegaly were observed. Neutrophils and eosinophils were normal. Serum ELISA for antibodies of nine different parasites (Toxoplasma gondii, Trichinella spiralis, Angiostrongylus cantonensis, Paragonimus westermani, Clonorchis sinensis, Schistosoma japonicum, Echinococcus granulosus, Cysticercus cellulosae, and Spirometra mansoni) was negative, and stool examination revealed no evidence of parasite infection. A diagnosis of an intraspinal tumour rather than a parasite was considered at first, and laminectomy from spinal segments L4 to S1 was performed. Intraoperatively, widespread inflammation was observed, and an approximately 6 cm-long, free-living worm was seen (figure, video). The whole body of the worm was removed. Pathological examination including gross morphology via hematoxylin and eosin staining, and sequencing of the complete mitochondrial cytochrome oxidase subunit 1 gene confirmed infection with Spirometra mansoni. Postoperatively, a systemic screen of the patient including the eyes (via ophthalmoscope), brain (cranial MRI), digestive tract (gastrointestinal endoscopy), thoracic cavity, and abdominal cavity (thoracic and abdominal CT scan), and faecal anti-sparganum (ELISA) showed no evidence of parasite infection in other organs, and treatment with praziquantel (25 mg/kg orally) was given. The patient remained symptom free without recurrence at a 1-year follow-up.