Localized Lichen Myxedematosus With Plasma Cell Light Chain Restriction: Is It the Exception or the Rule?

Lichen myxedematosus is a chronic cutaneous mucinosis that can present on a spectrum from localized cutaneous lesions to systemic disease of scleromyxedema. The clinical presentation of localized cutaneous lichen myxedematosus is waxy lichenoid papules, nodules, and/or plaques that have histopathologic findings of mucin deposition and a variable degree of fibroblast proliferation. There is an absence of serum paraproteins, and there are no other systemic causes of cutaneous mucinosis such as thyroid disease. The pathogenesis of lichen myxedematosus is unknown. We report 3 cases of localized cutaneous lichen myxedematosus with a light chain-restricted plasmacytic component by in situ hybridization. Our findings deliver an insight for disease pathogenesis and highlight for the first time, the significance of plasma cells in lesions of localized cutaneous lichen myxedematosus. We suggest that plasma cell light chain restriction could represent a clue to distinguish localized cutaneous disease from systemic disease.

Skin biopsies to assess response to systemic corticosteroid therapy in early-stage TEN: case report and review of the literature.

Toxic epidermal necrolysis (TEN) is a severe, mucocutaneous, necrolytic reaction to a variety of antigenic stimuli. The use of systemic corticosteroids in the treatment of TEN is controversial because of a lack of randomized, controlled, prospective studies, and because the effects of steroid therapy vary depending on the dosage and time of its administration during the course of TEN. Immediate intervention is crucial, and the response to corticosteroids in early-stage TEN can be difficult to clinically assess. In this report, we describe the use of serial skin biopsies to determine the efficacy of high-dose corticosteroids in patients with early-stage TEN. We present the case of a woman who was started on antiepileptic therapy with phenytoin sodium and developed TEN shortly thereafter. She was treated with intravenous methylprednisolone acetate for 1 week. The progression of the skin eruption was halted and the patient's condition began to stabilize. Skin biopsy specimens taken before and after steroid therapy revealed substantial improvement of the lymphocytic infiltrate and arrested epidermal necrosis. Serial skin biopsies in patients with early-stage TEN are helpful in assessing the initial response to corticosteroids and thus guide further therapy.