Scleromyxedema

Scleromyxedema is a rare, cutaneous deposition disorder from the group of mucinoses, which can affect multiple organs and is virtually always associated with a monoclonal gammopathy. Cutaneous manifestations are usually generalized, 2 to 3 mm sized, dome-shaped or flat-topped, waxy, slightly red to skin-colored papules and sclerodermoid indurations. Neurological, rheumatological, cardiovascular, gastrointestinal, respiratory tract, renal and ophthalmologic manifestations can occur, with decreasing frequency. A serious and potentially lethal complication is the dermato-neuro syndrome which manifests with flu-like prodromes followed by fever, convulsions and coma. Untreated, scleromyxedema usually takes an unpredictable and potentially lethal progressive disease course over several years. According to a widely acknowledged classification by Rongioletti a diagnosis of scleromyxedema can be rendered when (1) generalized, papular and sclerodermoid eruption, (2) a histological triad of mucin deposition, fibroblast proliferation and fibrosis, and (3) monoclonal gammopathy are present, and (4) thyroid disease is absent. Apart from the classic microscopic triad, an interstitial granuloma annulare like pattern was also described. The pathogenesis of scleromyxedema is unknown. A potential role for various, as yet unknown serum factors has been discussed. An unequivocal causal relationship between paraproteinemia and disease manifestations could not be established to date. High dose intravenous immunoglobulins (IVIg) are the first-line treatment of choice according to the most recent European guidelines.

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.

Scleromyxedema

PURPOSE OF REVIEW

To synthesize the current known data on pathogenesis and treatment of scleromyxedema. This review will also highlight the clinical presentation, systemic features and outcomes and distinguishing features between scleromyxedema and scleroderma, as a common mimic.

RECENT FINDINGS

Most recent publications have focused on describing treatment responses with novel therapies, with the majority of cases reporting success with intravenous immunoglobulin. However, other therapies suggest promise as well in case reports, including bortezomib, thalidomide and stem cell transplantation. There is little information on pathogenesis; however, focus has been on the relationship between the mucin deposition and the monoclonal immunoglobulins that are seen in almost all patients with scleromyxedema.

SUMMARY

Scleromyxedema is a rare mucinous deposition disorder that shares clinical features with scleroderma but has important distinguishing features in clinical presentation and major organ complications that should be recognized. Patients typically respond well to therapy as highlighted in several larger series, but poor outcomes are reported in a few cases.

Generalized mucinosis in a patient with erythroderma

We describe an 81-year-old Japanese patient with erythroderma overlapping with widespread and symmetrical deposits of mucin in the upper dermis. Clinically, the mucinous lesions on the nape and upper trunk were localized papular mucinosis. Histologically, there was a perivascular infiltrate of lymphohistiocytic cells mingled with plasma cells in the upper dermis but no sclerosis. Immunohistochemical staining revealed that more than 90% of these infiltrating plasma cells produced immunoglobulin lambda-chain. Both the erythroderma and generalized mucinosis responded to topical steroid and PUVA therapy. To the best of our knowledge, this is the first case of erythroderma accompanied by generalized mucinosis.