Two cases of systemic amyloidosis with deposition of amyloid protein in the skin

We report two cases of systemic amyloidosis with deposition of amyloid protein in the skin. Case 1) A 49-year-old man complained of nausea seven months before the first medical examination. Subsequently, he had severe orthostatic hypotension and chronic diarrhea, resulting in 23 kg weight loss in a half year. Heart failure and polyneuropathy also gradually developed. Endoscopic biopsy revealed amyloid deposition in stomach, duodenum, ileum, cecum, and colon. He was diagnosed as lymphoplasmacytic lymphoma by bone marrow puncture. He was referred to our department for the diagnosis of 3-5 mm sized red papules scattered on his shoulder and back. Histologically, amyloid deposits immunoreactive to immunoglobulin light chain were confirmed in the papillary dermis, together with the perineural and perivascular areas of the subcutis, leading to the diagnosis of immunocytic amyloidosis. Case 2) A 77-year-old woman with rheumatoid arthritis for 37 years suffered from renal insufficiency due to secondary amyloidosis 21 years after the diagnosis of rheumatoid arthritis; thereafter, hemodialysis treatment was initiated at the age of 73 years. She developed pruritic erythema on her chest. On histology, amyloid A and β2-microglobulin-positive deposits were evident around sweat glands. We diagnosed the patient as reactive AA amyloidosis induced by rheumatoid arthritis associated with dialysis amyloidosis. In the present two cases, the amyloid deposits were found in both lesional and non-lesional skin, suggesting a usefulness of skin biopsy in the diagnosis of systemic amyloidosis.