Silicon-associated subcutaneous lesion presenting as a mass: a confounding histopathologic correlation

Liquid silicon used for soft tissue augmentation can produce different histologic patterns when implanted into the dermis or subcutis, depending on the degree of purification and the injected volume. The pure medical-grade silicon implanted in miniscule amounts in a controlled manner results in minimal fibroplasia without significant inflammation. The industrial-grade silicon contaminated by additives may remain dormant for years and eventually cause formation of extensive granulomas and disfiguring nodules. We report a case of a 35-year-old transsexual woman who presented with bilateral buttock masses. Histologic evaluation revealed collections of cells with lipid-containing cytoplasmic vacuoles resembling lipoblasts. This pattern can be clinically and histologically confusing for a neoplastic process, particularly when this adverse effect of adulterated silicon develops years after the injection.