Primary solitary retro-clival amyloidoma

Abstract

Background: Amyloidosis encompasses a group of disorders sharing the common feature of intercellular deposition of amyloid protein by several different pathogenetic mechanisms. Primary solitary amyloidosis, or amyloidoma, is a rare subset of amyloidosis in which amyloid deposition is focal and not secondary to a systemic process or plasma cell dyscrasia.

Case description: This 84-year-old female presented with history of multiple syncopal episodes, dysphagia, and ataxia. Motor strength was 3+/5 in the right upper extremity. Rheumatoid factor, cyclic citrullinated peptide (CCP), and anti-nuclear antibody (ANA) were normal. Serum and urine immune-electrophoresis detected no abnormal bands. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated a non-enhancing soft-tissue mass extending from the retro-clivus to C2 posteriorly, eccentric to the right with severe mass effect on the upper cervical medullary junction. Endoscopic trans-nasal debulking of the retro-clival mass was performed with occiput to C5 posterior instrumentation for spinal stabilization.

Conclusions: Primary solitary amyloidosis, unlike other forms of amyloidosis, has an excellent prognosis with local resection. Diagnosis requires special stains and a degree of suspicion for the disease. This is the first report to document an endoscopic trans-nasal approach for removal of a primary solitary amyloidosis of the retro-clivus. Management of vertebral amyloidoma involves aggressive local resection of the tumor when feasible and spine stabilization as the degree of tumor involvement mandates. Complete evaluation for the diagnosis of systemic amyloidosis is essential for the management and prognostication. Surgeons encountering such lesions must maintain high suspicion for this rare disease and advise pathologists accordingly to establish the correct diagnosis.

Keywords: Amyloidoma; cervical instrumentation; cervical spine; primary solitary amyloidosis.

Figure 1

Initial sagittal (a) and coronal (b) computed tomography scan obtained at presentation demonstrate a non-enhancing mass centered along the posterior aspect of the clivus and C2, eccentric to the right, with soft tissue air. Not associated with erosive bony changes of either the dens (c) or the body of C2 (d)

Figure 2

Sagittal T1-weighted (a) and axial T2-weighted (b) magnetic resonance imaging demonstrate a soft-tissue mass posterior to C2. The soft-tissue mass exerts severe mass effect on the upper cervicalmedullary junction with associated abnormal cord signal

Figure 3

Postoperative T1-weighted sagittal (a) and axial (b) magnetic resonance imaging demonstrate interval postoperative changes including partial debulking of the mass and evidence of the fat graft. There was improvement of the cord kinking at the cervical medullary junction, but persistent moderate canal stenosis. Lateral x-ray films demonstrate a stable construct (c)

Figure 4

Hematoxylin and eosin (H and E) stain reveals amorphous, eosinophilic deposits (a). Congo red stain under polarized light shows obvious apple green birefringence (b)

Figure 5

A 2-year postoperative MRI demonstrating complete resolution of retroclival lesion as well as no spinal cord compression