Nodular amyloidosis in a patient with systemic scleroderma.

Primary cutaneous amyloidosis may be characterized as macular amyloidosis, lichenoid amyloidosis, or nodular amyloidosis. Nodular amyloidosis results from the deposition of immunoglobulin light chains and may rarely be associated with systemic amyloidosis. We report an unusual case of a patient with systemic scleroderma who developed primary cutaneous nodular amyloidosis on the left lower leg. The diagnosis was confirmed with a skin biopsy with Congo red staining and a novel technique using a laser microdissection and mass spectrometry-based proteomic analysis method for amyloid protein characterization. A work-up for systemic amyloidosis was negative and the patient improved symptomatically with wound care. Patients with primary cutaneous nodular amyloidosis should be followed clinically over time for the possible development of systemic amyloidosis, although the risk of disease progression is likely low.