The spectrum of localized amyloidosis: a case series of 20 patients and review of the literature.

Localized deposition of amyloid may occur in individual organs, in the absence of systemic involvement. The reason for localized deposition is unknown, but it is hypothesized that deposits result from local synthesis of amyloid protein, rather than the deposition of light chains produced elsewhere. We identified 20 cases of localized amyloidosis at our institution between 1993 and 2003. There were 11 males and nine females in the group. The mean age at the time of diagnosis was 65.5 years. Organs involved included skin, soft tissues, oropharynx, larynx, lung, bladder, colon, conjunctiva, and lymph node. In six of nine patients typed, the amyloid light chain was lambda. In those patients where follow-up was available (mean 7.6 years), none developed systemic disease. Localized amyloidosis occurs in a variety of organ systems. Evolution into systemic amyloidosis was not seen in our series of patients, supporting the hypothesis of local production of amyloid protein in these cases.