Cytologic features of a pleural effusion after silicone breast implant rupture.

Pleural effusion is an extremely rare complication of ruptured breast silicone implants. Rupture may be related to a recent trauma or occur spontaneously, making its diagnosis more difficult. In the few reported cases, cytology did not play a relevant role in its diagnosis. We describe and illustrate a silicone foreign body reaction in a pleural effusion. Cytologic findings were so remarkable as to permit a specific diagnosis. The patient, a 37-year-old female with a history of previous bilateral breast implant surgery was admitted because of a pleural effusion. Computed tomography scan showed a left effusion with secondary atelectasis and bilateral breast rupture with lymph node "siliconomas." Cytologic analysis of the effusion showed well-defined droplets or globules of transparent material, in addition to a microvacuolized background. Where abundant silicone droplets induced a staining artifact of the smears. These were cellular with numerous macrophages containing large vacuoles displacing the nuclei to the periphery. Some had a signet cell ring appearance, while others showed multinucleation. Flow cytometry revealed a predominant macrophagic cell population. With the increasing use of silicone breast implants, rare complications such as pleural effusion may become more common. The pathologist must consider this possibility when extracellular transparent droplets or evidence of a foreign body-type reaction are present. The artifact appearance of the smears may help to suspect it. This rare complication must be always considered when evaluating effusions in patients with silicone breast implants.