Lichen myxedematosus (LM) is an idiopathic cutaneous mucinosis disorder, and monoclonal gammopathy of undetermined significance (MGUS) is a preneoplastic plasma cell disease with a monoclonal increase in globulin. Patients with LM combined with monoclonal gammopathy are normally diagnosed with scleromyxedema. However, we report a case of generalized papules combined with MGUS in a 78-year-old man who was eventually diagnosed with atypical or intermediate forms of LM because it only involved the skin, and the pathological type was not consistent with scleromyxedema. Few cases of atypical or intermediate forms of LM have been reported, so the course of atypical or intermediate forms of LM is unpredictable. We report the diagnosis and treatment of a case of atypical forms of LM to discuss the current understanding of the disease, hoping to provide a reference for clinical research on this disease.

A 41-year-old man was referred to our outpatient department with a diagnosis of urticaria with angioedema of 3 months duration. On examination, he had generalized coalescent waxy papules and diffuse periorbital swelling. Systemic examination was unremarkable except for limited finger flexion. Serum electrophoresis and thyroid function tests were normal. Histopathological examination showed normal epidermis and intradermal mucin deposition, which was diagnostic of lichen myxedematosus (LM). The patient showed prompt response to melphalan. Here, we report this case of atypical LM because the patient had generalized eruption with normal thyroid function along with the absence of monoclonal gammopathy.

An 18-year-old Japanese woman noticed a progressive appearance of nodules on both forearms and on the left cubital fossa and left thigh one year before her initial consultation at our department. Physical examination showed elastic hard, slightly elevated, shiny and yellowish to skin-colored nodules of 6 to 10 mm in size on her extremities. From laboratory and histopathological findings, nodular-type lichen myxedematosus was diagnosed and nodules showed complete remission following local injection of triamcinolone acetonide.