Silicone lymphadenopathy of the axilla: a potential for misdiagnosis as metastatic carcinoma on fine-needle aspiration cytology

Silicone lymphadenopathy is an uncommon but well-recognized complication of silicone implant placement resulting from migration of silicone to regional lymph nodes. In patients with prior breast implantation, silicone lymphadenopathy most commonly involves the axillary lymph nodes. Because axillary lymphadenopathy may reflect malignant disease, including metastatic carcinoma, thorough evaluation to exclude neoplasia is essential. Fine-needle aspiration cytology (FNAC) serves as a valuable initial diagnostic modality in the assessment of axillary lymphadenopathy; however, silicone-induced foreign body reactions within lymph nodes may be misinterpreted as metastatic malignancy when silicone lymphadenopathy is not included in the initial differential diagnosis. Herein, a case of axillary silicone lymphadenopathy initially misdiagnosed as metastatic carcinoma on FNAC is presented. This case highlights the importance of recognizing the distinctive cytomorphologic features of silicone lymphadenopathy, which may be sufficiently characteristic to prompt consideration of prior breast implant history during cytopathologic evaluation.