Xanthogranulomatous inflammation and spindle cell proliferation in response to silicone breast implant leakage

Background

Implant-based reconstruction after nipple or skin-sparing mastectomy is becoming more popular with increasing rates of breast cancer survivorship in Australia.1 One of the more common risks and complications associated with implant insertion is leakage and/or rupture of the implant.2 3 Documented pathological responses to extracapsular silicone leakage include: silicone-containing granuloma ‘giant cell’ formation, foam cell and lymphocyte migration, as well as ipsilateral axillary lymphadenopathy of silicone-containing multinucleated giant cells.4 Xanthogranulomatous inflammation is an uncommon chronic inflammatory process primarily marked by the presence of foamy macrophages (xanthoma cells) and has been documented to present as a benign mimic of a malignant mass.5 6 This specific type of inflammation is of unknown aetiology and has been recognised in many organ systems such as the renal or gastrointestinal system.7 8 However, involvement of the breast is limited to only a small number of case studies of mastitis. We report an exceedingly rare instance of mass-forming xanthogranulomatous inflammation in response to a leaking silicone implant, which was clinically concerning for malignancy.

Case presentation

A post-menopausal woman in her late 50s presented with leakage of bilateral breast implants as discovered by a positron emission tomography (PET)-computerized tomography (CT) scan performed as part of her workup for small bowel Langerhans cell sarcoma metastases. The implants were originally inserted 11 years from point of presentation for aesthetic purposes. This was on the background of essential thrombocytosis treated with low-dose aspirin, a myeloproliferative disorder (JAK2 V617F mutation positive), choriocarcinoma surgically managed by hysterectomy, skin cancers and hypothyroidism treated with thyroxine. She underwent menarche at age 13 years old, had one live birth, breast fed for 6 weeks and had never taken oral contraceptives or hormone replacement therapy. Her family history was remarkable for breast cancer in her second-degree relative diagnosed at the age of 70 years.

On examination, she had D-cup size breasts with grade 2 ptosis with no palpable breast lumps or axillary lymphadenopathy. The only remarkable finding was an inframammary fold rash that had been present for 1 year and treated with creams prescribed by her primary physician.

Investigations

The imaging results of the PET-CT scan revealed increased activity bilaterally behind her subpectoral implants. Subsequent T1 MRI showed bilateral extensive enhancement of soft tissue posterior to both implants, but greater on the right side and suggestive of either haematoma or proteinaceous material (figure 1). The enhancement extended to the underlying pectoral muscle and chest wall, and into the subcutaneous tissues of the upper abdomen. The radiographic findings were suggestive of a leakage but there was no evidence of intracapsular or extracapsular rupture. An additional finding was an enhancing, irregular, heterogeneously enhancing mass in the 10 o’clock position of the right breast of 1.9 cm diameter. There were no enlarged axillary or internal mammary lymph nodes visualised.

There was initial clinical concern for breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), which prompted an ultrasound-guided core biopsy of the suspicious right breast mass, as well as fine needle aspiration of any fluid detectable on ultrasound. The fine needle biopsy results illustrated foamy histiocytes and chronic inflammation, with no atypical lymphocytes and overall, no evidence of malignancy. The biopsy was consistent with a florid histiocytic response to leaking silicone implants.

Following investigative processes, the patient underwent surgical excision with biopsy as planned. The subsequent surgical management plan was bilateral implant removal with wide pattern reduction en bloc capsulectomy (figures 2–4).

Histopathology results of the tissue specimens (figure 5) retrieved from the surgery (right capsulectomy, right breast medial capsule, left breast inferior part of wide pattern reduction en bloc capsulectomy, right breast superior areolar tissue and left breast superior areolar tissue) revealed xanthogranulomatous changes and spindle cell proliferation (figure 6), with no evidence of lymphoma or other malignancy.

A broad immunohistochemistry panel was performed with key results detailed as follows: keratin stains (AE1/AE3, CK7, CK5/6) were all negative while histiocytic markers (CD68 and CD163) highlighted the foamy and giant cells with CD3 and CD20 showing a mixed T and B cell population. CD30 was negative. Ziehl-Neelsen and Fite organism stains were negative for mycobacteria.

In this patient’s case, the abnormal imaging findings were not due to a malignant process, but rather a rare and benign but strikingly exuberant xanthogranulomatous inflammatory response to breast implant leakage.

Treatment

The surgical plan of bilateral implant removal with wide pattern reduction en bloc capsulectomy (figure 2) was curative with no subsequent anti-cancer or adjuvant treatment required.

Outcome and follow-up

The patient currently remains alive and well with a complete return to daily activity. She continues to follow up with the breast surgeons every 3 months.