Radiological pitfall: Siliconoma in internal mammary lymph node mimics breast cancer recurrence

The Spectrum of Non-neoplastic Changes Associated With Breast Implants: Histopathology, Imaging, and Clinical Significance

Breast implant-associated anaplastic large cell lymphoma has been recognized as a distinct entity in the World Health Organization classification of hematolymphoid neoplasms. These neoplasms are causally related to textured implants that were used worldwide until recently. Consequently, there is an increased demand for processing periprosthetic capsules, adding new challenges for surgeons, clinicians, and pathologists. In the literature, the focus has been on breast implant-associated anaplastic large cell lymphoma; however, benign complications related to the placement of breast implants occur in up to 20% to 30% of patients. Imaging studies are helpful in assessing patients with breast implants for evidence of implant rupture, changes in tissues surrounding the implants, or regional lymphadenopathy related to breast implants, but pathologic examination is often required. In this review, we couple our experience with a review of the literature to describe a range of benign lesions associated with breast implants that can be associated with different clinical presentations or pathogenesis and that may require different diagnostic approaches. We illustrate the spectrum of the most common of these benign disorders, highlighting their clinical, imaging, gross, and microscopic features. Finally, we propose a systematic approach for the diagnosis and handling of breast implant specimens in general.

Prevalence, clinical characteristics, and management of silicone lymphadenopathy: A systematic review of the literature

INTRODUCTION

Implant-based breast augmentations and reconstructions are one of the most common surgical procedures performed by plastic surgeons in the United States, which has rapidly increased in popularity since the 2000s. Silicone lymphadenopathy (SL) is a complication of breast implants that involves migration of silicone to nearby soft tissue/lymph nodes. Data on its clinical features and management is scarce.

METHODS

SL-related search terms were used to find articles in 3 databases. Of 598 articles, 101 studies met the inclusion criteria. Demographics, clinical presentation, workup, and management data were analyzed.

RESULTS

Of 279 cases of SL and 107 with information on initial diagnosis, 35 (33%) were incidental. The most common symptom was painless lymphadenopathy, followed by painful lymphadenopathy. 251 (95%) and 13 (5%) patients had silicone and saline implants, respectively. 149 (68%) patients had implant rupture. Axillary lymphadenopathy was the most affected region (136 cases, 72%), followed by internal mammary (40 cases, 21%), cervical/supraclavicular (36 cases, 19%), and mediastinal (24 cases, 13%) regions. 25% of patients underwent fine-needle aspiration, 12% core needle biopsy, and 59% excisional biopsy. 32% of cases underwent explantation and/or implant exchange. The most common indication for surgery was implant rupture. Histology showed multinucleated giant cells, large histiocytes, and silicone accumulation.

CONCLUSIONS

SL is a complication associated with breast implants. The majority of patients are asymptomatic, and most cases are managed conservatively. Minority need a biopsy and surgical interventions due to abnormal imaging, persistent symptoms, and/or implant rupture. Workup and management should be tailored to the patient.

Silicone-induced lymphadenopathy mimicking recurrence of breast cancer on positron emission tomography-computed tomography, correctly diagnosed on ultrasound

Silicone-induced lymphadenopathy is a rare complication associated with silicone breast implants. It is usually asymptomatic and found incidentally during imaging. We report a case of silicone lymphadenopathy in a patient who had undergone a mastectomy and breast reconstruction for breast cancer. During follow-up, a positron emission tomography-computed tomography examination revealed lymph nodes that were suspicious for cancer recurrence. However, sonography was able to correctly diagnose silicone-induced lymphadenopathy and exclude cancer metastasis.

Progressive silicone lymphadenopathy post mastectomy and implant reconstruction for breast cancer

A 56-year-old woman with a 12-year history of recurrent triple-negative invasive carcinoma of the breast presented with progressive enlargement of lymph nodes in the setting of established rupture of the ipsilateral silicone breast implant. Although this was proven to be benign on cytology, its progressive nature led to repeated core biopsies for histology, which were necessary given the high-risk nature of triple-negative breast cancer and the multiple proven previous recurrences. The histology demonstrated features of silicone deposits without evidence of malignancy. This case demonstrates the dilemma in surveillance of high-risk patients with breast cancer who have had previous silicone lymphadenopathy.

Imaging and Management of Internal Mammary Lymph Nodes

Internal mammary lymph nodes (IMLNs) account for approximately 10%-40% of the lymphatic drainage of the breast. Internal mammary lymph nodes measuring up to 10 mm are commonly seen on high-risk screening breast MRI examinations in patients without breast cancer and are considered benign if no other suspicious findings are present. Benign IMLNs demonstrate a fatty hilum, lobular or oval shape, and circumscribed margins without evidence of central necrosis, cortical thickening, or loss of fatty hilum. In patients with breast cancer, IMLN involvement can alter clinical stage and treatment planning. The incidence of IMLN metastases detected on US, CT, MRI, and PET-CT ranges from 10%-16%, with MRI and PET-CT demonstrating the highest sensitivities. Although there are no well-defined imaging criteria in the eighth edition of the American Joint Committee on Cancer Staging Manual for Breast Cancer, a long-axis measurement of ≥ 5 mm is suggested as a guideline to differentiate benign versus malignant IMLNs in patients with newly diagnosed breast cancer. Abnormal morphology such as loss of fatty hilum, irregular shape, and rounded appearance (which can be quantified by a short-axis/long-axis length ratio greater than 0.5) also raises suspicion for IMLN metastases. MRI and PET-CT have good sensitivity and specificity for the detection of IMLN metastases, but fluorodeoxyglucose avidity can be seen in both benign conditions and metastatic disease. US is helpful for staging, and US-guided fine-needle aspiration can be performed in cases of suspected IMLN metastasis. Management of suspicious IMLNs identified on imaging is typically with chemotherapy and radiation, as surgical excision does not provide survival benefit and is performed only in rare cases.

Internal Thoracic Lymphadenopathy in Breast Cancer

The internal thoracic (IT) nodal basin is a first-echelon drainage pathway in the breast, accounting for up to a quarter of its lymphatic drainage, primarily from the deep structures of the breast. The presence of internal thoracic node (ITN) metastases upstages the breast cancer (BC) patient to a minimum of clinical stage III disease. Medial tumors, deep tumors, young age, axillary nodal metastases, tumors of a high nuclear grade, lymphovascular invasion, and triple-negative hormone receptor status are predisposing factors for ITN metastases from primary BC. It has been observed that medial tumors carry a worse prognosis than lateral tumors when all other factors are equal, indicating that understaging of ITN has a significant impact on patient outcomes. Despite the established prognostic significance of IT adenopathy in BC, this nodal basin is not routinely staged due to the difficulty in accessing it and due to the controversy regarding its management. Since the initial ITN studies in the 1960s, improvement in imaging techniques and the availability of minimally invasive biopsy techniques have fueled renewed interest in ITNs and their clinical significance in BC. Radiologists who image and diagnose BC can offer more accurate staging assessments by consistently evaluating the IT nodal chain in the BC patient. In this article, the authors discuss current knowledge of the ITNs in BC and review ITN anatomy. The imaging appearance of pathologic ITNs using various modalities, potential mimics of IT adenopathy, and image-guided sampling techniques are described. A succinct discussion of the clinical management of ITN-positive BC and its challenges is also included. ^© RSNA, 2017.