Pleural silicone granuloma mimics pleural metastasis: Ruptured breast implant with silicone fistulising along a remote thoracotomy scar.

Silicone gel from ruptured implants can migrate to locations such as the chest wall, axillae, and upper extremities, resulting in granulomatous inflammation. Pleural silicone granulomas have rarely been reported in the literature. This is a rare case of pleural silicone granuloma, which demonstrates that silicone gel from an extracapsular implant rupture can fistulise into the pleural space along a remote thoracotomy scar.

Case report

A 71-year-old female presented for a routine examination after breast cancer and pulmonary carcinoid tumor. She had stage II invasive ductal carcinoma of the right breast 12 years ago and was treated with right radical mastectomy and silicone prosthetic implantation. She also underwent a right-middle lobectomy for a carcinoid tumor 10 years ago. Since the removal of carcinoid tumor, no evidence of disease recurrence had been found on the preceding surveillance CT studies (Fig.1).

Figure 1

71-year-old female with pleural silicone granuloma. Routine surveillance CT chest in soft-tissue (A) and lung (B) windows obtained several years before the current presentation demonstrated an intact silicone breast implant with no evidence of pleural or parenchymal abnormality (B). (White arrow denotes the old ipsilateral thoracotomy site.)

On examination, the right breast implant had diminished in size without reports of chest trauma. Computed tomography (CT) of the chest demonstrated diffuse pleural thickening along the right major fissure with several areas of focal pleural thickening, including a 17-mm nodule along the right major fissure (Fig. 2). A chest-wall soft-tissue mass just posterior to the right breast implant was concerning for recurrence of carcinoma (Fig. 3). No lymphadenopathy was seen on this examination. Whole-body positron-emission tomography (PET) showed mild F-18 fluorodeoxyglucose (FDG) uptake in the right pleural-based nodule and the chest-wall soft-tissue mass. The avidity of FDG uptake favored a nonmalignant etiology. Biopsy of the nodule along the major fissure, performed based on the clinical suspicion of pleural metastases, revealed silicone surrounded by foreign-body granulomatous reaction and no malignant cells (Fig. 4). The anterior chest wall mass was identified as ruptured breast implant that had formed a fistula at the previous thoracotomy site, extending into the pleural cavity. The ruptured implant and free silicone were removed from the chest wall and pleural space. A six-month followup showed no evidence of new pleural-based lesions.

Figure 2

71-year-old female with pleural silicone granuloma. Coronal and axial CT of the chest show a pulmonary nodule along the right major fissure with similar density to silicone implant (A and B) and mild FDG uptake (C).

Figure 3

71-year-old female with pleural silicone granuloma. Axial CT (A) shows an asymmetrically smaller right breast implant with folding of the collapsed shell (linguine sign) as well as an extracapsular soft-tissue density posteriorly, adjacent to the old thoracotomy scar. The appearance suggests rupture of the breast implant with extracapsular extension of its content. The soft-tissue density demonstrates mild FDG uptake (B) consistent with a silicone granuloma secondary to ruptured implant.

Figure 4

71-year-old female with pleural silicone granuloma. Biopsy of right pleural-based nodule demonstrated granulomatous inflammation with numerous vacuoles containing refractile material (arrows), consistent with silicone.

Discussion

Pleural silicone granuloma is a rare complication of implant rupture. Most silicone granulomas have been found within the breast tissue or regional lymph nodes (1, 2). Hirmund et al. first documented a patient with ruptured silicone-gel implants who developed pleural effusion containing silicone (3). Levine et al. described the first reported case of fibrothorax due to the inadvertent introduction of silicone from ruptured breast implants at the time of cardiac surgery (4). In our reported case, the patient’s implant remained intact for up to 10 years after thoracotomy, eliminating the possibility that silicone was introduced into the pleural space during her previous lobectomy. The chest CT and surgical biopsy findings confirmed that the implant material had fistulised into pleural space along the prior thoracotomy scar, forming a pleural silicone granuloma along the right major fissure.

Pleural silicone granuloma can mimic pleural metastases in patients with ruptured silicone breast implants. Mild FDG uptake in these pleural lesions is attributed to surrounding granulomatous inflammation. Scars from remote thoracotomy may provide a potential pathway for ruptured silicone to fistulise into the pleural space.