Nodular amyloidosis: review and long-term follow-up of 16 cases.

OBJECTIVES

To review the clinical presentations of nodular amyloidosis, examine these cases for evidence of plasma cell monoclonality, and obtain long-term follow-up data on progression to systemic amyloidosis.

DESIGN

Retrospective case series with long-term follow-up data obtained by phone survey.

SETTING

Mayo Clinic, Rochester, Minn, and Mayo Clinic, Jacksonville, Fla.

PATIENTS

All patients diagnosed with nodular amyloidosis between 1971 and 2001.

MAIN OUTCOME MEASURES

Clinical records and histopathologic characteristics were reviewed. Polymerase chain reaction to assess immunoglobulin gene rearrangement and immunohistochemical analysis to detect kappa and lambda light chain restriction were performed on paraffin-embedded specimens. Patients were contacted by phone to determine if progression to systemic disease had occurred.

RESULTS

We identified 16 patients with nodular amyloidosis. Mean age at diagnosis was 60.8 years (range, 41-87 years). Eight (50%) of 16 patients had acral involvement. Immunohistochemical analysis demonstrated light chain restriction in 6 of 10 patients. At the time of diagnosis, no patient was known to have systemic amyloidosis. One patient, however, had a serum monoclonal lambda protein and died 4 years later secondary to systemic amyloidosis. Follow-up data were obtained in 14 of the remaining 15 patients, with a mean follow-up time of 10 years (range, 8 months to 24 years). None of the 14 patients had signs or symptoms suggesting progression to systemic amyloidosis.

CONCLUSIONS

Nodular amyloidosis affects both sexes during middle age, with a tendency to affect acral sites. The relatively high rate of light chain restriction in our series provides further evidence for the presence of a local plasma cell clone. Progression to systemic amyloidosis is uncommon.