Head and Neck Imaging

Amyloidosis

disease complex defined by the presence of extracellular deposition of amyloid, an insoluble fibrillar protein material. Amyloidosis is clinically classified into a systemic (about 85%) and a localized (about 15%) form. Systemic amyloidosis is a serious and usually fatal condition, occurring in patients with immunocyte dyscrasias or chronic inflammatory conditions; there also exist rarer heredofamilial types. In its localized form, amyloidosis frequently involves the head and neck region; the larynx is affected most frequently (61%), followed by the oropharynx (23%), trachea (9%) and nasopharynx (3%). Amyloid deposits occur submucosally, but mucosal ulceration has been reported. On CT, the lesion usually appears as a relatively well defined homogenous submucosal mass lesion with soft tissue density, without evidence of bone destruction or associated lymphadenopathy head and neck; contrast enhancement is variable, calcifications may be seen. On MRI, a marked T2 hypointensity has been reported in some cases, but this finding does not seem to be consistent.

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