Papular mucinosis (scleromyxoedema) complicating diffuse systemic sclerosis: clinical features and electron microscope observations

Sclerodermalike syndromes: Great imitators

Sclerodermalike syndromes (SLSs) comprise diseases with mucin deposition (eg, scleromyxedema, scleredema), with eosinophilia (eg, eosinophilic fasciitis), metabolic or biochemical abnormalities (eg, nephrogenic systemic fibrosis), or endocrine disorders (eg, POEMS syndrome, or polyneuropathy, organomegaly, endocrinopathy, monoclonal lymphoproliferative disorder, and hypothyroidism). Chronic graft-versus-host disease may also show sclerodermalike skin changes. Inherited progeria syndromes with early aging (eg, Werner syndrome) and a heterogeneous group of hereditary disorders with either skin thickening (eg, stiff skin syndrome) or atrophy and tightening (eg, acrogeria) can also imitate classic systemic sclerosis (SSc). In addition, SLSs can be provoked by several drugs, chemicals, or even physical injury (eg, trauma, vibration stress, radiation). In SLSs, the distribution of skin involvement seems to be atypical compared with SSc. The acral skin involvement is usually missing, and lack of Raynaud phenomenon, scleroderma-specific antinuclear antibodies, the absence of scleroderma capillary pattern, and internal organ manifestations indicate the presence of an SLS. Skin involvement is sometimes nodular, and the underlying tissues can also be affected. For the differential diagnosis, a skin biopsy of the deeper layers including fascia and muscle is required. Histology does not always allow differentiation between SSc and SLSs; therefore, the diagnosis is often based on the distribution, quality of cutaneous involvement, and other accompanying clinical features.

Review of Primary Cutaneous Mucinoses in Nonlupus Connective Tissue Diseases

Lichen myxedematosus is an idiopathic, cutaneous mucinosis with 2 clinicopathologic subsets. There is the generalised papular and sclerodermoid form, more properly termed scleromyxedema, and the localised papular form. We report the first case, to our knowledge, of lichen myxedematosus in association with rheumatoid arthritis as well as a case in association with dermatomyositis. An up-to-date literature review on cutaneous mucinoses and connective tissue diseases, excluding the common association of primary and secondary mucinoses with systemic lupus erythematosus, was also performed.

[Strip papular mucinosis associated with systemic sclerosis]

INTRODUCTION

Other than discreet infra-clinical mucinous deposits observed during many inflammatory dermatoses, clinically visible dermal mucinosis can sometimes be associated with collagenosis. It is usually lupus and very rarely scleroderma. In this case, no confusion with papular mucinosis must be made.

CASE REPORT

A 51 year-old woman presented with infiltrated erythematous lesions in strips on the inner sides of the thighs and legs, associated with myalgia, arthralgia and puffy fingers. Mixed connective tissue disease was the initial diagnosis. The clinical picture was rapidly completed by sclerodactylia, telangiectasia, a Raynaud's syndrome and esophageal involvement leading to the diagnosis of CREST-type systemic scleroderma. The biopsy of the erythematous strip lesions revealed a dermal mucinosis. Treatment with hydroxychloroquine led to the regression of the mucinous lesions and the stabilization of the scleroderma, which, four years later, had not developed further.

DISCUSSION

Dermal mucinosis can accompany lupus erythematosus, in rare cases dermatomyositis and, in exceptional cases, scleroderma. The clinical presentation varies with large infiltrated plaques, reticulated or papulo-nodular lesions. Conversely, strip lesions such as those observed in our patient have never been reported till now. The association of a localized dermal mucinosis and a scleroderma must not lead to the erroneous diagnosis of papular mucinosis of clearly differing prognosis. The occurrence of a mucinosis during collagenosis might be related to enhanced synthesis of mucin by the fibroblasts mediated by the inflammatory cytokines, increased in this context.

Papular mucinosis associated with generalized morphoea

A 67-year-old white man is described who had large sclerotic plaques with a violaceous border on his back and abdomen and a scleroderma-like induration on the legs, sparing the feet. Additionally, he had multiple skin-coloured, large, sometimes centrally depressed papules and nodules on the nape of the neck, back and upper limbs. These occurred in both the normal and sclerotic areas. Histologically, large amounts of focal mucin were seen in the upper dermis consistent with the diagnosis of papular mucinosis and associated with typical underlying features of scleroderma. No paraproteinaemia was found. We excluded scleromyxoedema on clinical, histopathological and laboratory grounds and diagnosed our patient as having generalized morphoea with papular mucinosis. We are aware of only two reports of large cutaneous deposits of mucin associated with scleroderma.

Scleromyxedema

Scleromyxedema is a sclerotic variant of papular mucinosis, in which lichenoid papules and scleroderma-like features are present. We describe a patient with scleromyxedema with IgG type lambda chain paraprotein, a systemic sclerosis-like illness, and myositis. The patient's serum contained Scl 70 antibodies, characteristic of scleroderma. Electromyography showed signs of acute myositis and the creatine phosphokinase (CPK) level was elevated. Multiply passaged fibroblasts from the patient's skin lesions showed altered growth response in vitro. The patient was treated with cyclosporin (4 mg/kg/day) with improvement.

Scleromyxedema: a complete response to prednisone

Scleromyxedema is a disorder characterized by a typical rash due to the accumulation of mucin in the dermis. It is always associated with a monoclonal protein in the serum and can have a wide variety of systemic manifestations. We describe a 40-year-old woman who had scleromyxedema associated with a monoclonal G lambda protein. Severe systemic symptoms included fatigue, esophageal dysmotility, and myopathy. Symptoms resolved completely with oral prednisone therapy, and she remained in clinical remission 24 months after use of prednisone was discontinued. Scleromyxedema is commonly treated with alkylating agents, which have been associated with pronounced morbidity and mortality. We suggest that oral corticosteroid therapy may be a reasonable initial choice for treating this disease and that alkylating agents be reserved for corticosteroid-refractory disease.