Complex chest wall reconstruction after excision of malignant phyllodes tumour

Investigations

Contrast-enhanced CT scan showed a multilobulated exophytic heterogeneously enhancing mass of size 18.5×5.3 cm in the anterior chest wall. Mass was seen abutting the right 2nd−7th rib and left 3rd−5th rib, costal cartilages and insinuating between ribs causing loss of extrapleural fat without any rib erosion. No mediastinal and axillary lymphadenopathy was found. No distant metastasis was noted. Biopsy of the mass showed fibroepithelial lesion with stromal overgrowth with increased mitosis suggestive of malignant phyllodes.

Treatment

A staged procedure was planned for the patient. During the first surgery, wide local excision of the left chest wall tumour with excision of left 3rd–5th rib along with intercostal muscle and parietal pleura was performed. Thoracic cavity was closed with polypropylene mesh. Pedicled lattismus dorsi myocutaneous flap was harvested, placed over the mesh and sutured (figure 2). Debulking of the tumour up to the ribs was performed on the right chest wall. Residual raw area over the chest wall was covered with split thickness skin graft. During the postoperative period, patient was managed in the intensive care unit and was extubated on second postoperative day. Patient developed lobular pneumonia of the left lung which resolved after 2 weeks of antibiotic treatment.

Second surgery of the patient was performed after 3 weeks, meanwhile the tumour on the right chest wall had recurred, and a multilobular exophytic growth developed (figure 3). Wide excision of phyllodes tumour with 2nd–7th ribs and lateral border of sternum of right anterior chest wall, parietal pleura, right crus of the diaphragm and the lower lobe of the right lung which had invasion by tumour was performed. Defect of the diaphragm and anterior chest wall was reconstructed using scaffold made from Steinmann pins and polypropylene mesh. Pedicled greater omentum flap was harvested based on the left gastroepiploic artery, and it was placed anterior to the mesh, then omentum surface was reconstructed with split thickness skin graft, and the wound was dressed with negative pressure wound dressing. Patient was extubated on postoperative day 1. After recovery from the surgery, adjuvant chemotherapy (based on ifosfamide and epirubicin) and radiotherapy were given. Two months after completing her adjuvant therapy, patient expired after developing an episode of pneumonia and respiratory failure.

Discussion

Phyllodes tumour constitute 0.5% of all breast tumours.1 WHO classifies phyllodes tumours in three groups as benign, borderline and malignant based on histopathological features such as tumour margins, stromal cellularity, stromal cell atypia, mitotic activity, stromal overgrowth and the presence of malignant heterologous elements.5 Involvement of axillary lymph nodes is rare in this disease. They are not encapsulated tumours and have lobulated surface. They are known to have high recurrence rate, with 15% recurrence after R0 resection and much higher recurrence after incomplete excision.2 Phyllodes tumours are occasionally characterised by very rapid growth; they can present with destruction of surrounding structures and skin by direct invasion or by pressure necrosis. Chest wall involvement requiring excision of ribs and complex reconstruction has been rarely reported.3

Phyllodes tumours present as a diagnostic dilemma in the preoperative period as the radiological features, and histopathological features resemble that of fibroadenoma. Fine needle aspiration cytology has poor sensitivity and specificity in detecting phyllodes tumour; thus, core needle biopsy is preferred, but it is not highly accurate in differentiating between fibroadenoma and phyllodes tumour. On surgical excision, the histopathology of benign phyllodes tumour closely resembles fibroadenoma which has significant clinical impact as even benign phyllodes tumour have high recurrence rate of 10%–20%.5 Malignant phyllodes tumours are characterised by marked stromal cellularity, stromal atypia, high mitotic activity of >10/10 HPF and occasional presence of sarcomatous component. Borderline phyllodes tumour have features between the spectrum of benign and malignant phyllodes tumour with mitotic activity of 5–9/10 HPF. Misjudging a phyllodes tumour as a benign lesion can result in inadequate surgical excision margin and high chances of recurrence.

Treatment of the phyllodes tumour require complete excision of the tumour with 1 cm surgical margin without sentinel lymph node biopsy or axillary lymph node dissection. This can be achieved by wide local excision of the tumour but occasionally requires mastectomy in large and recurrent tumours. In our patient during the first procedure, only debulking of tumour was performed on the right side of the chest wall which had positive margins; this could have been the reason for rapid tumour recurrence before the second procedure. Adjuvant radiotherapy have been shown to reduce the recurrence rate and metastasis rate in these patients compared with simple surgical treatment.6 Role of adjuvant chemotherapy and hormonal therapy is not yet well established.

Management of chest wall involvement by phyllodes tumour requires complex reconstruction. Cross sectional imaging with CT scan or MRI will be required for delineating the extent of involvement and for planning resection. Involved skin, myofascial layers, lung and diaphragm should be removed en bloc with the tumour. In cases of intercostal muscle or rib involvement, ‘one rib above and one rib below’ might require removal for achieving complete resection, while in most adult patients, resection of intercostal muscles of the adjoining spaces will be sufficient to achieve 1 cm negative margins of resection.7 At the posterior extent of rib excision, the intercostal arteries and veins are ligated followed by excision of the rib and the intercostal muscle.

After extensive resection, skeletal reconstruction is required to restore chest wall function and protection of the visceral organs. Various options are available for skeletal reconstruction in these patients. Flexible prosthetic mesh is one of the most used method for smaller defects. Mesh made from absorbable or non-absorbable material, permeable or impermeable material, synthetic or bio prosthesis material can be used like polypropylene, polytetrafluoroethylene or polyglactin. In larger chest wall defects, using mesh alone can lead to excessive paradoxical chest movement hence avoided. Rib fixation with metallic rib substitutes made from titanium or stainless steel is used for larger chest wall defects. They provide better chest function, protection to visceral organs and avoid paradoxical chest movement. They can be used in combination with prosthetic mesh. Soft tissue coverage after complex chest wall reconstruction is necessary, and the huge defect always requires local flaps, pedicled flaps or free flaps to achieve the reconstruction.

Appropriate rehabilitation is essential in the postoperative period in these patients to avoid postoperative respiratory complications. Adjuvant radiotherapy is often provided to decrease chances of further recurrence. Close follow-up is needed for early detection of recurrence and long-term complications of complex reconstruction of the chest wall.