DP25 Widespread subcutaneous nodular kappa light chain amyloidosis

Abstract A 69-year-old woman was referred to the dermatology department for evaluation of multiple widespread subcutaneous lesions involving neck, torso and limbs. These lesions, initially diagnosed in community as lipomas, had been slowly progressing size number 3 years. She remained systemically well. Her only medical history essential thrombocythaemia. took no regular medication. On examination, there were appreciated on palpation with overlying epidermal change. The patient experiencing pain a sciatic distribution. Magnetic resonance imaging femur showed 12-cm enhancing area nodularity encasing nerve. Computed tomography chest, abdomen pelvis subcutaneous, ill-defined, soft tissue anterior abdominal wall lymphadenopathy or organ abnormality. Deep incisional biopsies from two separate locations completed. There an unremarkable epidermis dermis. In fat, septae appeared thickened alongside elastic fibres prominent multifocal granulomatous reaction high degree elastophagocytosis. aggregates plasma cells that displayed cytological atypia. situ hybridization strong kappa light chain restriction. Plasma protein electrophoresis completed confirmed paraprotein band gamma region IgM kappa. Full blood count revealed platelet (585 × 109 L–1) but otherwise normal renal liver function, bone profile, lactate dehydrogenase, B2 microglobulin, Bence–Jones proteins infection screen. Congo red stain performed original histological samples. This apple green birefringence under polarized light-confirming amyloid. Haematology marrow biopsy, which normal. Referral National Amyloid Centre made. Serum amyloid P scan visceral involvement. diagnosis subtype (AL) has since commenced rituximab, bortezomib (Velcade®), cyclophosphamide dexamethasone (R-VCD) chemotherapy at 4-weekly intervals over 4-month period. Primary localized cutaneous amyloidosis is characterized by extracellular deposition skin without evidence systemic involvement often subtyped into macular, papular nodular. Amyloidoma (tumoral amyloidosis) rare defined solitary deposit are four case reports literature deposits, one these cases AL (light chain) vs. (AA) subtype. nodules restricted neck (Nguyen TU, Oghalai JS, McGregor DK et al. Subcutaneous nodular amyloidosis: report review literature. Hum Pathol 2001; 32:346–8). To our knowledge, this first amyloidosis.