Primary solitary amyloidoma of thoracic spine: a case report and review of the literature.

Primary solitary amyloidoma of spine is a rare subset of amyloidosis in which the amyloid deposition is focal and not secondary to a systemic process or plasma cell discrasia. Only seventeen cases of spine involvement have been reported. We report a 71-year-old man with 3 months history of ataxia and frequent falls. On the 4th month paraparesis developed. Magnetic resonance imaging of the dorsal spine revealed a lesion involving the T-9 vertebral level with significant spinal cord compression. Decompressive laminectomy with posterior instrumentation and fusion from T8 to T10 was performed. Histopathology revealed abundant amyloid deposits. No evidence of myeloproliferative disease or systemic amyloidosis was found. The patient showed marked neurological improvement with residual mild spastic gate 6 months after surgery. When occurring primarily in a localized anatomic area, the prognosis of amyloidoma is excellent, and cure can be expected by local resection. It is important to know that diagnosis requires a high index of suspicion and, ultimately, adequate tissue biopsy for histopathological studies.