Tophaceous gout of spine causing neural compression

Objective To investigate the imaging and clinicopathological features of spinal tophaceous gout in thoracic vertebra and the key points of its diagnosis and treatment, in order to improve the recognition of this disease. Methods and Results A 36-year-old male was admitted because of weakness and numbness of both lower extremities for 2 months with progressive aggravation for 2 weeks. MRI revealed an extradural mass compressing the spinal cord at T9-10. The tumor was totally removed by piecemeal resection. Histopathological examination of the fresh specimen by light microscope demonstrated brown linear crystals, which showed strong birefringence in polarized light microscope, located in fibrous connective tissue, with local bone invasion and foreign body granuloma. However, histopathological examination of the removed specimen demonstrated white amorphous materials, with scatteredly distributed remaining brown linear crystals, which showed single refraction in polarized light microscope. The final pathological diagnosis was tophaceous gout. The patient was followed-up for 6 months. He stopped taking anti-uric acid drugs by himself and could walk with crutch. Conclusions Tophaceous gout of spine is caused by uratic deposition in spinal joints, which needs to be differentiated from other intraspinal extradural space-occupying lesions like tuberculosis, central nervous system lymphoma, metastatic tumors and lipomyoma. A definite diagnosis of tophaceous gout of spine requires histopathological examination detecting uratic crystals. DOI: 10.3969/j.issn.1672-6731.2016.11.013