Teaching Case

A 32-year-old female from Venezuela with a history of silicone injection 15 years ago, who arrived at the emergency department with pain and swelling of buttocks, for which an ultrasonography (US) and computed tomography (CT) was performed. At physical examination, the presence of pain, swelling, and deformity of her buttocks was evident.

A 32-year-old female from Venezuela with a history of direct silicone injection 15 years ago who arrived at the emergency department with pain and swelling of buttocks for which a grey-scale US was performed, showing an increased noise that prevents the visualization of deeper structures. This finding correlated with the classical “snowstorm” appearance which suggests the presence of free silicone in buttocks (Fig.1)  

A CT image was then performed in order to assess the presence of granulomas or infection, the image revealed multiple and bilateral isodense subcutaneous nodulations with fat stranding in buttocks, associated with gluteus maximus and superficial soft tissue involvement, findings that may be in correlation with silicone granulomas (siliconomas) (Fig 2). 

Silicone injection for cosmetic purposes was banned by the U.S Food and Drug Administration (FDA) in 1991, but it continues to be performed in developing countries especially because of the markedly cost reduction in comparison to other FDA approved cosmetic procedures [1,2]. Silicone is usually injected in the breast and gluteal region, in which the patient develops a host tissue response, resulting in volume expansion secondary to fibrous encapsulation of the silicone, which ends up in granulomas formation. Clinically, the presence of silicone is asymptomatic and is usually detected as an incidental finding in mammograms, thorax, or abdominal CT. Silicone complications can be divided into focal (cellulitis, abscess, myositis, migration of the material, skin hyperpigmentation, fibrosis, subcutaneous nodules, granulomas, necrosis, ulceration, fistula) and systemic (hypersensitivity pneumonitis, silicone embolism syndrome, pulmonary oedema, sepsis) [3].
Imaging modalities are important to rule out complications of silicone injection [2]. Characteristic CT findings of silicone granulomas are the presence of soft tissue densities with surrounding fat stranding, that may be accompanied by peripheral calcification [4]. A characteristic finding on US is the snowstorm appearance caused by increased noise on the image, usually associated with anechoic or hypoechoic nodules or masses representing silicone globules [5]. The final diagnosis is usually made by magnetic resonance imaging (MRI) in which multiple hypointense nodules are identified in T1-weighted images with a variable signal on T2-weighted sequences that depends on the temporary evolution of the granuloma, finding T2 hyperintensity if the reaction is inflammatory and T2 hypointensity if the reaction is fibrous [6].
The treatment of silicone-induced granulomas varies mainly according to whether the lesion is diffuse or well circumscribed. For diffuse lesions, it is preferred systemic or intralesional corticosteroids and immunomodulating therapies such as etanercept, tacrolimus, imiquimod, and antibiotics such as doxycycline [7]. While for more focal and well-circumscribed lesions, surgical excision or even laser treatment can be used [7]. All treatment modalities demonstrated an adequate response and an improvement in the patient's prognosis, however, tapering the dose of corticosteroids has been associated with relapse of the inflammatory process [8].
Teaching points: When a patient arrives at the emergency department with swelling, pain of buttocks, and a history of free silicone injection, the physician must strongly consider the diagnosis of silicone granulomas.
Written informed patient consent for publication has been obtained.