Discrete papular mucinosis-a rare subtype of lichen myxoedematosus

Dermatologic manifestations of thyroid disease: a literature review

Introduction

Thyroid hormone is considered one of the key regulatory hormones for skin homeostasis. Multiple organs are affected by the release of peripheral thyroid hormones (T4 and T3) further regulating various functions at a cellular level. Specifically, skin is considered an important target organ in which the thyroid hormone has a significant impact. Multiple skin diseases are associated with thyroid hormone dysregulation. However, other striking dermatologic manifestations are seen in nails and hair as well. Hypothyroidism, hyperthyroidism, and thyroid cancer can have an array of cutaneous manifestations, and we present the recent updates in this field.

Methods

A PubMed search was performed for updates in any new skin disease findings and treatments between 2010 and 2022. Research published in the past decade and previously known foundational skin findings associated with thyroid disease were presented in this review.

Conclusion

Cutaneous manifestations of thyroid disease is one of the first notable signs of thyroid hormone dysregulation. This article reviews the recent updates on the thyroid and skin interplay, and it further discusses overt visible findings and various available treatment modalities.

Thyroid dermopathy and acropachy

Graves' disease is an autoimmune condition commonly associated with thyroid dysfunction and with anti-thyroid antibodies, usually TSH receptor stimulating antibodies. Thyroid autoimmunity also may be associated with extra thyroidal manifestations. Most common extra thyroidal manifestation is ophthalmopathy. Less common is thyroid dermopathy, usually occurring in pretibial area. Dermopathy is almost always associated with ophthalmopathy and in severe cases with acropachy. A common antigen with thyroid in tissues of the skin and the eyes, most likely TSH receptor, is involved in pathogenesis of extra thyroidal manifestations. Presence of dermopathy and acropachy are predictors of severity of autoimmune process. Local corticosteroid application is the standard therapy for dermopathy. Response to therapy is good in mild cases and poor in severe cases. Immune modulators and biotherapies are undergoing randomized trials for ophthalmopathy component of Graves' disease. Any therapy proven to be effective for ophthalmopathy can be utilized in future for management of dermopathy.

Discrete papular lichen myxoedematosus: a rare subtype of cutaneous mucinosis

Primary cutaneous mucinoses are characterized by abnormal mucin deposits in the skin. Discrete papular lichen myxoedematosus (DPLM) is an unusual subtype. Only 11 of the cases described in the literature to date showed no relation to human immunodeficiency virus (HIV) infection. We report a 21-year-old woman with numerous symmetrical asymptomatic papules on her trunk, arms and thighs. Results of investigations were normal. On histological examination, the upper dermis showed a focal mucin deposit. DPLM can be associated with HIV or C hepatitis virus (HCV) infection and therefore an early diagnosis is very important.

[Discrete papular mucinosis]

BACKGROUND

Papular mucinosis is a rare dermatological disorder characterized by papules, nodules or plaques resulting from mucin deposits in the dermis, and to a certain degree, from fibrosis, without thyroid dysfunction.

CASE REPORT

A 42-year-old man consulted for symmetrical papular lesions on the face, neck and shoulders. The lesions had gradually spread over some 20 years. Laboratory findings were normal. Histopathologic examination showed diffuse mucin deposits in the superficial and middle layers of the dermis, thick bands of collagen, proliferation of fibroblasts and mild perivascular infiltration by mononuclear cells. All of these findings pointed to a diagnosis of papular mucinosis.

DISCUSSION

The specific interest of this case is the predominant involvement of the face and the spread of the lesions. According to the updated Rongioletti classification, this patient is presenting an atypical and novel form of papular mucinosis of a "mild papular" type with facial involvement. The 20-year history without systemic involvement or paraprotein suggests to us that this localized form will not develop into the systemic form or scleromyxoedema.