The Defect Repair After a Giant Malignant Phyllodes Tumor Resection of Breast Using a Kiss Flap

Malignant phyllodes tumors of the breast are fairly rare and fast-growing tumors. They are not sensitive to chemotherapy or hormonal therapy. Therefore, the primary treatment for malignant phyllodes tumors is wide surgical excision. Herein, we report a case study which featured a 26-year-old woman presented with a giant malignant phyllodes tumor measuring 20 × 17 × 13 cm. In order to reduce the chance of local recurrence, treatment for these types of tumors usually involves extensive excision with at least 1 cm of surgical margins. The patient underwent mastectomy with negative surgical margins, which left a large skin defect of 25 × 15 cm. Repair of such a large skin defect is a challenge to breast surgeons. This is the first reported case in which a “kiss” flap was successfully used to repair the skin defect created after resection of a giant malignant phyllodes tumor. The kiss flap could be considered as an effective and simple method to repair large chest wall defects after resection of giant phyllodes tumors.


Introduction
Phyllodes tumors are fairly uncommon fibroepithelial neoplasms accounting for 0.3-0.9% of all breast tumors [1]. They are fast-growing tumors with benign, borderline, or malignant behavior, depending on histologic features including stromal cellularity, infiltration at the tumor's edge, and mitotic activity. Their size ranges from 1 to 45 cm, and they may occupy the entire breast. Giant phyllodes tumors are typically defined as those > 10 cm in diameter [2]. Reports in the literature have been focused on surgical approaches to tumor resection. An adequate surgical margin is preferred with extended lumpectomy or mastectomy to prevent recurrence and metastasis. However, repair of the skin defect created after wide excision with at least 1 cm of surgical margins is a great challenge to breast surgeons. Repair with a pedicled latissimus dorsi kiss flap has not been reported in the literature (the kiss technique is first to harvest two or more small skin paddles from the donor site, which have the same size and shape, then rearrange them side-by-side at the recipient site, letting them "kiss" together to get a single, wide, unified flap, so named "kiss flap"). We report a case of giant malignant phyllodes tumor treated with mastectomy followed by successful defect repair with a kiss flap.

Patients and Techniques
Kiss flap is a surgical technique for patients who underwent enormous tumor resection and with huge skin defect. The surgery included a 26-year-old Chinese woman presented with a giant mass on her right breast, which had enlarged in the past year. This patient was included in September 18, 2016. We obtained written informed consent from the patient presented in this case report in accordance with the Helsinki Declaration of 1975. The patient consented to the treatment and the use of her data, including photos, for research and publication. This study was approved by the medical ethics committee.

Results
Her familial and personal history was non-contributory. Except for the breast tumor, laboratory tests showed no significant findings. Physical examination revealed a protruding and hardened palpable mass occupying almost the entire right breast (Fig. 1a). The mass measured approximately 20 × 17 × 13 cm. The skin had been stretched thin, with areas of ulceration and engorged superficial veins. Bilateral axillary lymph nodes were palpable, which are relatively soft and have good activities. A mammogram was not feasible because of the tumor size. Ultrasound of the breast mass indicated a heterogeneous echo and internal structures containing small cystic components, calcification, and hyperechoic separations, and was classified as BI-RADS 4 ( Fig. 1b). Multiple enlarged hypoechoic bilateral axillary lymph nodes were detected, and some of them had lost their normal internal architecture and fatty hila. Magnetic resonance imaging (MRI) revealed a giant, lobulated mass with heterogeneous signal intensity, as well as septa and wellcircumscribed margins, indicating typical features of phyllodes tumor (Fig. 1c). Image-guided core needle biopsy was performed twice, but a definite diagnosis was not obtained. The patient underwent mastectomy and axillary lymph node biopsy. Before surgery, a "kiss" flap was carefully designed to cover the skin defect. First, we detected and localized the thoracodorsal artery by color Doppler ultrasound; then, a paper template of the huge skin defect was created. The template was then split into two small pieces of the same size and shape. These paper templates were strategically oriented onto the right back donor sites, allowing direct primary donor-site closure, and an exact match of the assembled flaps to the large defect. The skin defect was 25 × 15 cm. The template was used to mark the flaps on the patient's right back. The location of the two-lobed flap depended on the vascular pedicle to ensure paddles were nourished by independent myocutaneous perforators from the thoracodorsal artery. An incision was made along the outlined semicircular skin island until the latissimus dorsi muscle was visualized, making sure both flaps were connected with the muscle. Before transposing the flaps to the chest wall through a subcutaneous tunnel, the two narrow skin paddles were arranged side by side and carefully sutured together to create a "kiss" flap. Finally, the donor site was sutured in layers, and the kiss flap was placed according to the design to cover the chest defect and sutured without tension ( Fig. 2a-e). The wound recovered well (Fig. 2f, g). The resected primary tumor measured 18 × 14 × 14 cm (Fig. 2h). The cut surface of the tumor was white to gray with hemorrhagic foci (Fig. 3a). There was no involvement of the cutting edges, skin, tissue beneath the nipple, or superficial fascia. The sentinel lymph nodes were negative (0/4) with IHC biomarkers ER( −), CK( −), CD34(+ / −), P63( −), and SMA(-). Genetic testing showed no TP53 mutation. Postoperative pathology revealed a high-grade malignant phyllodes tumor with multifocal necrosis (Fig. 3b, c). After surgery, the patient was given six cycles of chemotherapy with docetaxel (160 mg), epirubicin (100 mg), and cyclophosphamide (800 mg). The patient also received twenty-five Fig. 1 Imaging data of the patient. a Preoperative view. b Ultrasound of the right breast mass shows small cystic components, calcification, and hyperechoic separations. c Magnetic resonance imaging of the breast reveals a giant, lobulated mass with heterogeneous signal intensity, as well as septa and well-circumscribed margins, typical of a phyllodes tumor fractions of adjuvant chest irradiation treatment (total of 50 Gy). The patient was followed up for more than 4 years postoperatively, and there was no local recurrence or distant metastasis. Since she recovered well, the patient now is planning to have a delayed implant breast reconstruction plus fat grafting.

Discussion
Phyllodes tumor is a disease of the epithelial and stroma tissue in the breast. It is classified as benign, borderline, and malignant. Malignant tumors have high stroma  cellularity and tend to be permeative, whereas benign tumors have low stroma cellularity and are circumscribed [3]. Malignant phyllodes tumors are distinguished only pathologically by identification of marked stromal cellularity, more than 5 mitoses per 10 high-powered fields, invasive margins, and marked stromal overgrowth [4]. Giant phyllodes tumors are rare fibroepithelial breast neoplasms typically > 10 cm in diameter by definition [2]. In general, it is difficult to differentiate phyllodes tumors from benign fibroadenoma by clinical presentation, radiology, or even core needle biopsy. The most accurate diagnosis of breast phyllodes tumor is postoperative pathology. Unlike breast cancer which can be downsized by neoadjuvant therapy, phyllodes tumor is not sensitive to chemotherapy, radiotherapy, or endocrine therapy [5,6]. Surgery is regarded as the primary treatment method of phyllodes tumors. Negative margins rather than surgery type, such as extended lumpectomy or total mastectomy, determine the recurrence rate [7]. The National Comprehensive Cancer Network guidelines [8] advocate a wide excision with surgical margins of 1 cm or more. A negative margin is an independent prognostic factor for disease-free survival and local recurrence [9,10]. Patients with a positive margin and malignant histology should undergo further surgery to obtain clear margins.
Extended lumpectomy or mastectomy with adequate surgical margins is the best choice for large malignant phyllodes tumors. Although a "fish-tail" incision has the ability to close even a larger skin defect as large as 15 cm × 15 cm without resorting to an additional flap [11], the resulting large skin defect always requires a skin graft or transplanted flap. To the best of our knowledge, this case is the first documented use of a kiss flap to repair the large skin defect resulting from removal of a giant malignant phyllodes tumor of the breast. There are some other options to repair the defect such as a transverse rectus abdominis myocutaneous (TRAM) flap or a deep inferior epigastric artery perforator (DIEP) flap. TRAM and DIEP can immediately reconstruct a new breast after mastectomy. Although DIEP and TRAM have little influence on pregnancy, the young girl has not been married or pregnant; she worried about a long scar on the abdominal wall would affect beauty and future pregnancy. Moreover, DIEP and TRAM need a long operative time and are highly traumatic, and DIEP requires microsurgical techniques. The young girl also worried about a quick recurrence soon after surgery, so she refused complicated immediate breast reconstruction such as DIEP and TRAM, and wanted to choose a simple procedure. The latissimus dorsi flap is close to the postoperative chest wound and usually be used to repair the chest wall defect after breast dissection. However, the skin of the back lacks elasticity; the donor area cannot be directly sutured and generally requires a skin graft if the width of the flap exceeds 8 cm. This prolongs postoperative recovery and limits the wide application of the latissimus dorsi flap. The kiss flap involves the excision of double skin paddles, which has an independent blood supply from the donor stem. These paddles are spliced in the recipient area; then, they "kiss" each other side-by-side to create a much larger flap, accurately matching the size of the defect. This technique allows flexible design of the flap shape, while increasing the surface area of skin flap coverage and minimizing incision dehiscence and non-healing complications. A careful presurgical flap design is necessary to make maximum use of the limited human tissue available and ensure minimum damage while performing the autologous tissue transfer. The functional and aesthetic outcome of the donor site should also be considered. In this case, the postoperative flap had a good appearance with no hyperplastic scar and the activities of shoulder joint were not affected. The outcome of this case suggests that the kiss flap is a simple and feasible technique for repair of large skin defect following giant phyllodes tumor resection. If there is no recurrence or metastasis more than one year after surgery, the patient may plan a delayed breast reconstruction. After communication with the patient, she planned to have a delayed implant breast reconstruction plus fat grafting. For some patients with small breasts, wing-shaped skin component of latissimus dorsi myocutaneous flap design may be a good choice since it not only facilitates the primary closure of the donor site defect in a VY or M-plasty manner but also creates a mild breast mound and may avoid the use of implants and its associated complications [12].
Local recurrence of phyllodes tumors has been associated with positive margins, younger age, larger tumor size, and malignant pathologic diagnosis [1,13,14]. The tumors rarely spread via the lymphatic system, and axillary lymph node metastasis rate is < 5%. Therefore, axillary lymph node dissection is unnecessary, yet the removal of suspicious axillary lymph nodes is recommended [15,16]. In this case, since the tumor is too large, a sarcoma mixed with breast cancer components is not ruled out, and the axillary lymph nodes were palpable, so, we have an axillary sentinel lymph node biopsy. However, postoperative pathology proved that all the lymph nodes were negative. Studies have shown that adjuvant radiotherapy can lower the rate of local reoccurrence, particularly for patients with positive margins for borderline and malignant tumors [17][18][19]. Margin-negative resection combined with adjuvant radiotherapy is very effective for local control and prevention of recurrence. According to NCCN guidelines [8], adjuvant chemotherapy is not recommended since there is no evidence that adjuvant chemotherapy provides benefit in reduction of recurrence or metastasis. Adjuvant chemotherapy is not the standard care since it is of controversial value for malignant phyllodes tumors, yet some institutions support doxorubicin-based adjuvant chemotherapy for first-line treatment of breast sarcomas, especially with > 5.0 cm large high-risk tumors [20,21]. During postoperative follow-up, no local recurrence or distant metastasis were found.

Conclusion
The kiss flap could be considered as an effective and simple method to repair large chest wall defects after resection of giant phyllodes tumors.

Declarations
Consent for Publication Yes.

Conflict of Interest
The authors declare no competing interests.
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