Correspondence Address:
Lin Li
Department of Dermatology, Chengdu Second People�SQ�s Hospital Chengdu
China

Full Text

Sir,

The classification of lichen myxoedematosus (LM) is based on the criteria that the clinical appearance of the skin lesions, their histopathological characteristics, and whether they are associated with systemic involvement. According to the most recent classification, absence of thyroid disease is a diagnostic criterion for LM. [1] In this study, we report a case with atypical discrete papular mucinosis or lichen myxoedematous with an exuberant presentation of plaques in the presence of symptomatic thyroid dysfunction.

A 28-year-old Asian man was referred to our department with a 6-year history of multiple small, asymptomatic waxy papules and plaques. The lesions started from the dorsal aspect of the hands and gradually spread to the extensor portions of the extremities, trunk, and face. A review of systems revealed that about 3 years after the lesions' first appearance, he had developed symptoms of progressive tightening of the skin, limitation of mouth opening, wet cough, dysphagia, and hoarseness but without lalopathy. He also complained of being tired, suffering weight loss (nearly 30 kg), and decrease in physical strength, especially in the past 1 year. Acitretin was given but was unsatisfactory in controlling symptoms. Skin examination revealed multiple waxy, opalescent, flat-topped, 2- to 4-mm papules. The coalesced papules formed plaques on the face. The coalescence of papules on the glabella results in longitudinal folding and gives the appearance of a leonine facies, with slight ectropion [Figure 1]. Generalized sclerodermoid induration was present on the skin of the extremities and trunk.{Figure 1}

The hematoxylineosin staining of a cutaneous biopsy showed loosely separated collagen fibers in the upper dermis with increased fibrous tissue and fibroblasts, suggesting mucinous deposition. The Alcian bule staining (pH, 2.5) showed the presence of a large amount of mucin in the upper and mild dermis [Figure 2]. A diagnosis of scleromyxoedema was made.{Figure 2}

The Hematoxylin and Eosin staining of a cutaneous biopsy showed loosely separated collagen fibers in the upper dermis with increased fibrous tissue and fibroblasts, suggesting mucinous deposition. The Alcian bule staining (pH, 2.5) showed the presence of a large amount of mucin in the upper and mild dermis [Figure 2]. A diagnosis of scleromyxedema was made.

Results of the Results of the laboratory tests including routine blood test, urinalysis, liver and renal function, and immunological testing were within normal limits. Levels of serum anti-double-stranded DNA, antinuclear antibody, anti-Sm, anti-Ro (SSA), anti-La (SSB), Scl-70 antibodies, erythrocyte sedimentation rate (ESR), and rheumatoid factor (RF) were all within normal limits. The patient tested negative for human immunodeficiency virus (HIV) and treponema pallidum, the only abnormalities being a slight monoclonal gammopathy on serum protein electrophoresis and a higher than normal c-reactive protein (CRP) (7.0 mg/L; normal range <6). Imaging showed no decreased motility of the esophagus. However, thyroid-stimulating hormone (TSH) was 6.26 IU/mL (normal range 0.38-5.57), and free T4 was 8.64 pmol/L (normal range 10.58-21.03), with T3 and free T3 in normal limits.

We present a case that clinically and histologically should be included in the LM group: Scleromyxoedema represents the generalized subtype, with mucin deposition and proliferation of fibroblasts and monoclonal gammopathy. Papular mucinosis associated with thyroid dysfunction has been reported previously, which, as in the present report, represent cases of atypical lichen myxedematosus. [2],[3],[4],[5] We reviewed earlier literatures and found that a subtype called papular mucinosis associated with thyroid disorder was reported before, which however, is not present in the updated classification due to its rarity. Moreover, reports that thyroid hormone replacement therapy led to an improvement in cutaneous mucinosis associated with hypothyroidism reinforced the association between these two metabolic diseases. [3] The reason for the formation of the papular depositions of mucin in hypothyroidism is still unknown but may represent an exaggerated response of the local tissue to a generalized abnormality of the connective tissue metabolism induced by thyroid hormone disturbance. There is evidence that in hypothyroidism the excess accumulation of hyaluronic acid in the skin and other tissues results from a proportionally greater reduction in its degradation compared with its synthesis. [2] However, the exact relationship between these two diseases remains to be further studied. Besides, the course of the atypical forms is unpredictable and should be followed up carefully.

Therefore, we believe that the presence of thyroid disease should not constitute an exclusion criterion for a diagnosis of lichen myxoedematosus. The current diagnostic criterion and classification of LM deserve further definition.

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