Utility of Dual-Energy Computed Tomography for Evaluation of Silicone within Internal Mammary Nodes

Case Report

Austin J Clin Case Rep. 2017; 4(1): 1112.

Utility of Dual-Energy Computed Tomography for Evaluation of Silicone within Internal Mammary Nodes

Doerge S, Glazebrook KN*, Leng S and McCollough C

Department of Radiology, Mayo Clinic, USA

*Corresponding author: Glazebrook KN, Department of Radiology, Mayo Clinic 200 First Street SW, Rochester, MN 55905, USA

Received: October 19, 2016; Accepted: January 11, 2017; Published: January 31, 2017


Silicone implants are commonly used for breast reconstruction following breast cancer surgery. Over time the silicone envelope weakens and may rupture. The free silicone may remain within the fibrous capsule (intracapsular rupture), extend into the adjacent breast tissue (extracapsular rupture) or may be taken up by macrophages and can be found in the regional nodes. It is well recognized to be deposited in axillary lymph nodes however there have been few case reports of internal mammary silicone adenopathy. Silicone granulomata within axillary and internal mammary nodes can have high tracer uptake on F-18 FDG positron emission Tomographic Computed tomography (PET/CT), mimicking breast cancer. Dual-energyCT (DECT) allows determination of the density and atomic number of tissue thereby providing material composition information. We present a case of silicone axillary and internal mammary lymphadenopathy mimicking recurrent breast cancer on PET/CT, but with silicone clearly identified on DECT.

Keywords: Dual energy computed tomography; Silicone implants; Breast cancer


CT: Computed Tomography; DC: Dual Energy; PET: Positron Emission Tomography; FDG: Fludeoxyglucose

Case Presentation

A 51 year old woman was diagnosed with Wilm’s tumor of the right kidney at the age of 5. She received 2 courses of radiation therapy which extended from her right shoulder to her right hip. Due to right breast asymmetric development, she underwent left breast reduction surgery and right mastopexy at age 18. In 2002 she underwent bilateral breast reconstruction with a Becker tissue expander implants. In 2004 she noted a palpable right mass which was found to be multifocal Nottingham Grade II (of III) invasive mammary carcinoma with mixed ductal and lobular features, the largest mass being 1.8 cm, with three positive axially nodes. She underwent bilateral mastectomies with delayed Becker expander reconstruction. She presented in 2015 with new onset of fatigue and headaches with bilateral breast pain. F18 – FDG PET/CT showed multiple hypermetabolic right axillary, right subpectoral and bilateral internal mammary nodes (Figure 1) with maximum SUV of 5.8 in a right axillary node suspicious for metastases. Ultrasound of the right axilla demonstrated a snow storm appearance of an enlarged right axillary node consistent with silicone within the axillary node (Figure 2). A fine needle aspiration was performed which was negative for malignancy but showed numerous foreign body giant cells (Figure 3). Breast MRI (1.5T Signa LX Echospeed, General Electric medical Systems, Milwaukee, WI) consisting of axial T2 weighted IDEAL sequence, axial and sagittal silicone sensitive series and pre- and postcontrast Vibrant 3D T1 weighted gradient series, showed intact Becker dual lumen implants. The silicone sensitive sequences did show increased signal intensity within the enlarged IM nodes (Figures 4-6) and patchy increased signal within the hilar region of right axillary nodes consistent with silicone however there was significant pulsation artifact. Noncontrast Dual-energy CT (DECT) was performed using dual-source CT scanner (SOMATOM Force, Siemens Healthcare, Forchheim, Germany) using tube potentials of 100 and 150 kV. An additional tin filter was added to the 150 kV beam to increase spectral separation. The patient was scanned prone with a single acquisition using a prototype breast stand modified from a breast MRI coil for CT use. The volume CT dose index (CTDIvol) was 6.62mGy, and the dose length product (DLP) was 235mGy· cm. Sagittal and coronal reformats were performed with axial reconstructions of 1.5 mm. Images were analyzed using the 3-material decomposition algorithm of the dualenergy CT software (SygnoVia Dual Energy, Siemens Healthcare) with “Liver VNC” workflow. The mixed CT images (average of 100 and 150 kV images) showed adenopathy in level I and level II right axially nodes as well as bilateral internal mammary adenopathy. On the silicone color-coded images, the internal mammary adenopathy was uniformly colored consistent with silicone (Figure 7). Only patchy color was seen in the right axillary adenopathy (Figure 8) correlating with the heterogeneous signal intensity for silicone on MRI. Due however to the high clinical suspicion for metastases with enlarged hypermetabolic IM and axillary nodes, core needle biopsy of the largest right axillary node was performed and this revealed silicone granuloma. The patient then underwent explanation of the bilateral breast implants. The right was ruptured but the left was grossly intact.