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.