[A case of POEMS syndrome with enlarged pancreas due to IgG4-related autoimmune pancreatitis].

A 57-year-old man developed bilateral hands and feet numbness, followed by weakness with the legs and skin pigmentation. These symptoms became gradually worsened, and we made a diagnosis of POEMS syndrome because of progressive polyneuropathy, skin changes, IgG lambda type monoclonal proteinemia, and elevated level of serum vascular endothelial growth factor (VEGF). Diffusely enlarged pancreas was noticed in computed tomography. Serological, radiological, and histological findings revealed enlarged pancreas was due to IgG4-related autoimmune pathogenesis. After high dose chemotherapy with autologous peripheral stem cell transplantation, his clinical manifestations, IgG lambda type monoclonal proteinemia, and elevated level of serum VEGF were improved, whereas diffuse enlargement of the pancreas did not change. This is the first case report of POEMS syndrome accompanied with IgG4-related autoimmune pancreatitis. Co-existence of monoclonal and polyclonal plasma proliferative changes in the present patient may provide keys to clarify common mechanisms shared by these two rare disorders, POEMS syndrome and IgG4-related autoimmune disease.