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.
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Silicone-induced granuloma in buttocks
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1. Ultrasound (US) Findings: Multiple small nodular or lump-like echogenic abnormalities are observed in the subcutaneous tissue and muscle layers of both buttocks. In certain areas, a disorganized echogenic pattern appears, creating a “snowstorm” artifact, which suggests the possible presence of free silicone oil or other foreign materials.
2. Computed Tomography (CT) Findings: Within the soft tissues of both buttocks, irregular soft-tissue density shadows are seen, with varying degrees of fat stranding in the surrounding area. Blurring at the interface with the soft tissue is noted, along with signs of local fibrosis and possible mild calcification in some regions.
Based on the patient’s history of free silicone (silicone oil) injections in the buttocks and the characteristic features shown on the current ultrasound and CT images, the potential diagnoses include:
Based on the patient’s history and typical radiological presentation, silicone oil granuloma remains the primary consideration.
Taking into account the patient’s injection history, current clinical presentation (bilateral buttock pain, swelling, deformity, and tenderness), and the ultrasound and CT imaging characteristics, the most likely diagnosis is: Silicone Oil Granuloma in the Buttocks Following Silicone Oil Injections.
If further confirmation is required, MRI (which may show multiple nodules with low or isointense signals on T1 and mixed high and low signals on T2) or pathological biopsy can provide additional evidence.
1. Treatment Plan
2. Rehabilitation and Exercise Prescription
Considering the patient’s local buttock pain and potential scar tissue, rehabilitation training should account for the following principles:
Disclaimer: This report is based solely on the available clinical and imaging information for reference analysis and cannot replace an in-person consultation or professional medical advice. If you have any questions or if your condition changes, please seek timely medical attention.
Silicone-induced granuloma in buttocks
