Steatocystoma multiplex is a condition where multiple slow-growing cysts appear, usually during puberty, on the body. They occur most commonly on the chest, armpits, and neck. These can get quite large in size, but are often not very raised and are covered by normal looking skin. The contents of these cysts are more liquid and odorless, often clear or slightly yellow in color. These types of cysts, benign and rare, are compared to epidermoid cysts, and actually could be called truly "sebaceous cysts" because they begin in the sebaceous glands. Treatment is not medically necessary, but many people seek removal because they don't like the appearance.
Eruptive vellus hair cysts appear as multiple, maybe even hundreds of 1-4mm skin-colored or hyper-pigmented dome-shaped papules (raised and swollen areas) on the mid-chest and upper extremities. Vellus hairs are short, fine hairs that line our skin making these cysts common. They tend to be smaller than steatocystomas and can have a central area of umbilication (dimpled center). Steatocystoma may at times have vellus hairs, and Eruptive Vellus Hair Cysts may have sebaceous glands (oil glands) in their lining, which leads some dermatologists to believe these two conditions may be related. Treatment is gentle extraction. There is a high chance of recurrence if a carbon dioxide laser is used to extract them, and topical retinoid tazarotene has also been used, but is considered inferior treatment.