Pharyngeal amyloidomas: Variable appearance on imaging

Abstract

Amyloidomas are rare tumor-like depositions of abnormally folded, insoluble proteins that may be seen in the setting of systemic amyloidosis or as isolated tumoral deposits. Focal, isolated amyloidomas carry an excellent prognosis whereas systemic amyloidoses do not. The ability to identify or suggest amyloidoma on imaging studies may help direct laboratory testing and eventual diagnosis. Amyloidomas involving the head and neck have been variably described from homogeneously T2 hypointense to iso-slightly hyperintense relative to skeletal muscle. Herein we present two patients with pharyngeal submucosal amyloidomas of differing sizes and imaging characteristics to emphasize their potential widely variable imaging appearance and broaden our knowledge of these rare lesions.

Keywords: Amyloidomas; amyloidoses; amyloidosis; head and neck; plasmacytoma.

Figure 1.

A 55-year-old female with bilateral retropharyngeal amyloidomas. PET/CT coronal image (a) demonstrates heterogeneous FDG uptake, with greatest FDG uptake within the amyloidomas’ upper nasopharyngeal component (thick arrows) and geographic regions of low FDG uptake within the lower lesions (thin arrows) at the oropharynx level. Contrast-enhanced neck CT axial image (b) at the upper oropharynx level reveals well-defined bilateral retropharyngeal masses, containing tiny calcifications on the left (small black arrow). On CT these masses demonstrate variable contrast enhancement that is more homogeneous and intense on the right (thick white arrow) than the left (thin white arrow). MRI coronal T2 (c), T1 (d) and post-contrast T1 (e)-weighted images demonstrate amyloidoma heterogeneity, with their upper FDG avid component appearing T2 and mildly T1 hyperintense relative to muscle with marked post-contrast enhancement (thick arrows). The inferior amyloidoma components (thin arrows), with predominant low FDG uptake, are mildly T2 and T1 hypointense to muscle, with heterogeneous, less intense contrast enhancement. Pathology slide (H/E stain, 10× magnification) (f) from oropharynx level biopsy of the right pharyngeal lesion demonstrates a heavy background of eosinophilia (black arrow) with scant plasma cells, and a focal collection of plasma cells within its superior aspect (thick white arrow). PET/CT: positron emission tomography/computed tomography; FDG: F-18 fluorodeoxyglucose; MRI: magnetic resonance imaging; H/E: hematoxylin and eosin.

Figure 2.

A 48-year-old female with nasopharyngeal submucosal amyloidoma. Contrast-enhanced CT axial image (a) reveals a submucosal non-enhancing lesion (thick arrow) containing two small calcifications (thin arrow) contiguous with an enlarged torus tubarius. MRI axial T2 (b), T1 (c) and post-contrast T1-weighted (d) images demonstrate the amyloidoma (arrow) relative to muscle to be T2 hyperintense, T1 isointense and non-enhancing. CT: computed tomography; MRI: magnetic resonance imaging.