steatocystoma multiplex of the breast
Steatocystoma multiplex is a rare familial hamartomatous malformation that is characterized by the presence of multiple intradermal cysts, and can result in abnormal breast examinations.
They usually appear during adolescence and progress with age.
The disease manifests as numerous palpable (usually mobile) intradermal oil cysts ranging from 2-20 mm in diameter. The cysts are usually asymptomatic although they can occasionally rupture to the skin surface and may become infected.
The cysts contain a clear oily liquid and small amounts of keratinous material.
There is a genetic predisposition and It is thought to have an autosomal dominant inheritance. Occasional sporadic cases have also been identified.
While features are best described radiologically in the breast, the cysts occur primarily on the trunk, proximal extremities, and external genitalia.
Mammography shows characteristic subcutaneous oil cysts as multiple, small, round lesions with a circumscribed margin, central fat density, and a peripheral high-density rim.
Sonography shows multiple nodules that are oval, relatively well marginated, and hypoechoic with posterior enhancement.
There is no increased risk of either breast or skin malignancy.
The differential for mammographic findings include: