What are mucinoses?
Mucinoses are a diverse group of uncommon skin disorders. All involve accumulation in the skin of abnormal amounts of mucin. This is a jelly-like complex carbohydrate substance, called hyaluronic acid, that occurs normally as part of the connective tissue in the dermis or mid-layer of the skin. The abnormal deposits that occur in mucinoses can be localised or widespread. They vary from minor cosmetic nuisances to potentially severe conditions involving internal organs. The underlying cause of this group of disorders is not well understood.
Extensive or generalised mucinoses include:
- Reticular erythematous mucinosis
- Follicular mucinosis
- Cutaneous lupus mucinosis
- Pretibial myxoedema associated with thyroid disease.
Localised mucinoses include:
- Lichen myxoedematosus (papular mucinosis)
- Acral persistent papular mucinosis
- Mucinous naevus
- Myxoid or digital mucous cyst
- Focal cutaneous mucinosis (see the pathology of focal cutaneous mucinosis): a harmless solitary lesion less than 1 cm in diameter that can be removed by surgical excision if required.
- Angiomyxoma: a benign tumour that can arise singly or in numbers. Multiple lesions may indicate the Carney complex in which the benign tumours may develop in the heart.
Deposits of mucin also occur as a result of other skin disorders (secondary mucinoses).