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.
*Larking Community Hospital, Miami, FL;
†Global Pathology Laboratory, Aurora Diagnostics, Miami Lakes, FL;
‡Pathology and Laboratory Medicine Service, Bruce W. Carter VAMC, Miami, FL;
§South Miami Dermatology, Miami FL; and
¶Neogenomics Laboratories, Irvine, CA.
Correspondence: Laszlo Karai, MD, PhD, 16250 NW 59th Avenue, Miami Lakes, FL 33014 (e-mail: firstname.lastname@example.org).
The authors declare no conflicts of interest.