Thoracic spinal cord compression by extradural tophus: a case report and review of the literature

Abstract

Study design: Case report and literature review.

Objectives: Gouty arthritis of the spine is rare. Gout presenting as back pain and quadriplegia may be difficult to distinguish from a spinal tumor. Symptoms vary, and the diagnosis is often delayed. We report an unusual case of thoracic spinal cord compression caused by extradural tophaceous deposits whose initial diagnosis had been lymphoid malignancy. To the best of our knowledge, this is only the second report of using single-photon emission computed tomography (SPECT) to diagnose spinal tophus.

Methods: We retrospectively reviewed the medical records, operative reports and radiographic imaging studies of a single patient.

Results: A 26-year-old man with severe tophaceous gout presented with a 4-month history of progressive weakness and dyschesia of both lower extremities. Coronal bone slices evaluated by SPECT indicated increased methylene diphosphonate uptake in the T9 and T10 pedicles. Pathology assessment revealed areas of amorphous substance containing urate crystals surrounded by inflammatory cells. The diagnosis was gouty tophus.

Conclusion: The position of the spinal tophus may be related to the 'S' type of spinal anatomical structure. Obesity and inactivity may be the two risk factors for spinal tophus. Every effort should be made to lower the serum uric acid level by maximizing the pharmacological regimen. We believe that laminectomy can effectively relieve spinal cord compression. It also improves the long-term prognosis for spinal gouty tophus. SPECT may be a viable method for differentiating spinal gout and a malignant tumor.

Figure 1

The swelling and tenderness of the patient’s feet skin (arrow). Computed tomography (CT) of bilateral feet scan and three-dimensional reconstruction showed lytic lesions on the foot bones and urate crystal deposition along the bilateral metacarsophalangeal joints.

Figure 2

(a) Thoracic CT scan demonstrated lytic cloud-like lesions localized to the facet joints and costovertebral joints of the T10–11 vertebral level and extended to bilateral intervertebral foramens. (b) Axial T1-weighted images showed that the lytic lesions in the left pedicles of T9 and T10 were isointense on T1-weighted imaging. (c) Emission computed tomography (SPECT) bone imaging examination (tracer: ⁹⁹Tc^m-MDP, tracer dose of 30 mCi) indicated an increase in methylene diphosphonate uptake in the right pedicles of T9 and T10.

Figure 3

(a) During the surgery, a large mass with white chalky material in the vertebrae thoracales was found eroding into the adjacent pars intra-articularis, accompanied by the tissue fibrosis. (b) The granule had a smooth edge and medium blood circulation. (c) Pathological results showed areas of an amorphous substance containing urate crystals surrounded by inflammatory cells and multinucleated giant cell granuloma (hematoxylin and eosin, ×200).