A 59-year-old woman had papular mucinosis and IgG(K) M component in the serum. Only three other cases of papular mucinosis in which the IgG M component had K-type light chains have been reported. Papular mucinosis seems to be a systemic rather than a solely cutaneous disease and may be related to plasma-cell dyscrasis. Its course is usually benign and chemotherapy may have an adverse effect.