Primary Solitary Retroclival Amyloidoma: A Case Report and Review of the Literature

Summary: Primary solitary amyloidoma of the spine is a rare disease characterized by focal deposition of amyloid. Here, we demonstrate the radiologic appearance of primary solitary amyloidoma of the spine on computed tomography and magnetic resonance imaging. The imaging findings revealed features of a nonspecific soft-tissue mass extending rostral and caudal from peri-C2 to the retroclivus with severe epidural cervical medullary compression.

Background: Primary solitary amyloidosis is a rare subset of amyloidosis in which the amyloid deposition is focal and not secondary to a systemic process. Solitary cervical amyloidosis is an exceedingly rare entity with exceptionally good prognosis, but requires diligence of the treating physician to establish the diagnosis and implement the appropriate surgical intervention. We present a case of primary cervical amyloidosis with extension to the retroclivus and discuss its presentation and management.

Purpose: This study aims to present a rare case of primary cervical amyloidosis with immediate follow-up and review the clinical presentation, characteristic imaging findings, diagnostic pathology, differential diagnosis, treatment algorithm, and prognosis of the disease entity. Previous reported cases of primary cervical amyloidosis will also be reviewed.

Study Design: This study is a report and review of the literature.

Methods: This 84-year-old female patient presented with a history of multiple syncopal episodes, dysphagia, and ataxia. Motor strength was 3 + /5 in the right upper extremity. Rheumatoid factor, CCP, and ANA were normal. The serum and urine immune-electrophoresis detected no abnormal bands. Computed tomography and magnetic resonance imaging demonstrated a nonenhancing soft-tissue mass extending from the retroclivus to C2 posteriorly, eccentric to the right with severe mass effect on the upper cervical medullary junction. Endoscopic transnasal debulking of the retroclival mass was performed with occiput to C5 posterior instrumentation for spinal stabilization.

Results: Intraoperative tissue specimens demonstrated an amorphous extradural pale mass. The biopsy specimen was positive to Congo red stain at histologic examination, with yellow-green birefringence to polarized light, which is characteristic of amyloidoma. Postoperatively, the patient regained full strength and ambulatory status. Overall, 1-week postoperative imaging demonstrated debulking of the retroclival mass with a stable spine construct.

Conclusion: Primary solitary amyloidosis is a rare subtype of amyloidosis, which unlike other forms of amyloidosis has an excellent prognosis with local resection. Diagnosis requires special stains and therefore a degree of suspicion for the disease. This is the first case report to document an endoscopic transnasal approach for the removal of a primary solitary amyloidosis of the retroclivus. Management of vertebral amyloidoma involves aggressive local resection of the tumor when feasible and stabilization of the spine as mandated by the degree of tumor involvement. Complete evaluation for the diagnosis of systemic amyloidosis is essential for the management and prognostication of each case. It is imperative that surgeons encountering such lesions maintain a high suspicion for this rare disease entity and advise their pathologists accordingly to establish the correct diagnosis.