Cutaneous diseases caused by monoclonal immunoglobulin and/or free light chains (monoclonal gammopathy of cutaneous significance).

BACKGROUND

Monoclonal immunoglobulin (M-Ig) and/or free light chains (FLC) can cause a wide range of organ and tissue damage. The most common are various forms of nephropathies, for which the term monoclonal gammopathy of renal significance was created, and a morphological classification was proposed by the "International Kidney and Monoclonal Gammopathy Research Group." Another large group consists of clinical entities where, among other things, various forms of skin damage occur. For these, the group designation monoclonal gammopathy of cutaneous significance was created. Although the etiopathogenesis is hematologic, the symptoms lead patients with this form of monoclonal gammopathy-related damage to dermatology clinics.

AIM: Dermatological publications from the last 5 years distinguish diseases with a clearly expressed etiopathogenetic connection to monoclonal gammopathy, defining a total of 12, and then mention other diseases in which the etiopathogenetic relationship is less clear. The group of skin diseases with a clearly demonstrated connection to monoclonal gammopathy includes: AL amyloidosis of the skin, cutaneous macroglobulinemia, skin changes in POEMS syndrome, scleromyxedema, scleroderma, diffuse normolipidemic xanthomas, necrobiotic xanthogranuloma, urticaria in Schnitzler syndrome, telangiectasia in TEMPI syndrome, localized erythema in AESOP syndrome, cryoglobulinemic skin changes, cutis laxa (loose skin). Among the diseases with a less clear connection to monoclonal immunoglobulin, we mention IgA pemphigus. The text provides brief descriptions supplemented with imaging documentation of cases we have encountered over the past 35 years.

CONCLUSION

If a dermatologist encounters the mentioned diseases, they should examine M-Ig and FLC, and in the case of a positive finding, consult with a hematologist regarding the possibility of targeted therapy.