Steatocystoma multiplex

Steatocystoma multiplex is an uncommon skin condition first described by Jamieson in 1873, and coined by Pringle in 1899. It is a disorder of the pilosebaceous unit characterised by the development of numerous sebum-containing dermal cysts on the upper trunk, and other sites rich in sebaceous glands.

This chapter is set out as follows:

• Although steatocystoma multiplex can be inherited in an autosomal dominant fashion, most cases are sporadic

• Cysts manifest predominantly during adolescence and early adulthood, although sporadic cases can occasionally arise in older patients
• Both males and females may be affected

Distribution

• The trunk, particularly the presternal skin, and proximal limbs are the most commonly involved sites 
• Much less commonly lesions may also appear on the face and acral sites

Morphology

• Multiple skin-coloured to white-yellow, smooth, dermal papules and nodules ranging in size from 3 mm to 3 cm
• There is no central punctum
• The cysts are often freely movable 
• Lesions can occasionally become inflamed, increase in size, and rupture. In such cases secondary bacterial colonisation and sinus tract formation may ensue
• There may be widespread comedone formation

The differential diagnoses include nodular acne, and in familial cases the condition can be associated with eruptive vellus hair cysts.

• There is little in the way of effective medical therapy, although oral isotretinoin may reduce the size of pre‐existing cysts and/or reduce the rate of development of new lesions

• Treatment with an ablative laser, such as a carbon dioxide laser, appears to be effective