Endogenous formaldehyde is generated in the human body.When the system of endogenous formaldehyde generation with scavengation is damaged,excess accumulation of endogenous formaldehyde induces vascular endothelial injury,atherosclerosis,myocardial damage and neurodegenerative diseases.Studies show that endogenous formaldehyde is one of the key factors during the process of cardiovascular and cerebrovascular diseases.Moreover,polyphenols are used as capture agents of endogenous formaldehyde to prevent and treat cardiovascular and cerebrovascular diseases.

A rare case of POEMS(polyneuropathy,organomegaly,endocrinopathy,M-band,skin changes) syndrome associated with multicentre Castleman's disease and thrombocytosis is reported in a 48-year-old man.Three years prior to the presentation,he developed a series of symptoms without obvious triggers,including persistent myalgia and myasthenia of extremities,abnormal skin sensation (burning),gradually increased roughness and pigmentation of skin,thickening and mild induration of lower-extremity skin giving an ichthyosiform appearance.Two years prior to the presentation,electromyography indicated peripheral neuropathy,and computed tomography(CT) revealed hepatomegaly,splenomegaly,lymphadenectasis,ascites,hydrotborax and hydropericardium.Multiple biopsies of lymph nodes indicated an obvious vascular proliferation between lymphoid follicles with the involvement of lymphoid follicles,which,together with the histochemical findings and special staining results,was suggestive of hyaline-vascular type Castleman's disease.Three months prior to the presentation,painful erythema emerged and gradually spread in both thighs,with a progressive deepening in the colour of central lesions,and flushing of periphery lesions.Two months prior to the presentation,a soybean-sized nodule arised in the erythema on the right inner thigh,which was then ulcerated with a little pus left and a shallow ulcer formed.Physical examination revealed a mild atrophy of lower-extremity muscles,with muscle strength graded as 5 for bilateral upper extremities and as 4 for bilateral lower extremities.The skin was rough,diffusely pigmented and thickened,giving an ichthyosiform appearance,which was more apparent in the extremities than in the trunk.An atropurpureus patch sized 5 cm × 2 cm was seen respectively in bilateral inner thighs; the surface of the central lesions was coarse and covered with dry crusts and scales,giving a rough paperlike appearance,and the peripheral lesions were surrounded by a faint prunosus halo,which faded on pressure.Laboratory examination found hypothyroidation,reduced insulin secretion,abnormal calcium and phosphorus metabolism,and progressive thrombocytosis.Immunofixation electrophoresis showed that the serum was weakly positive for IgG type M protein.This patient was diagnosed with POEMS syndrome associated with multicentre Castleman's disease and thrombocytosis.After treatment with methylprednisolone and thalidomide,the main symptoms of POEMS syndrome were improved,whereas thrombocytosis progressively aggravated.