Localized Foot Amyloidosis From Monoclonal B Cell Lymphoma

Localized cutaneous amyloidosis is a rare dermatologic finding necessitating extensive diagnostic workup to include serum protein electrophoresis, fat pad biopsy, and imaging to rule out underlying hematologic disease or systemic involvement. Herein we detail a case of AL amyloidoma in a 73-year-old male that presented as chronic violaceous patches of the bilateral feet. Punch biopsy of these lesions revealed congo red-positive amyloid deposits, and further testing revealed an underlying monoclonal B cell lymphocytosis that remained stable at 6 months follow up. This case highlights the importance of distinguishing localized amyloidoma from systemic disease and other hematological malignancies.