Multidisciplinary minimally invasive planning for synchronous breast cancer and thymoma: a scarless single-stage surgical strategy—a case report and literature review

Introduction

In Europe, breast cancer is the most prevalent cancer among women. According to estimates, the incidence in the European Union (EU)-27 in 2022 was 375,000 (1). Conversely, thymic tumors are rare and account for less than 1% of all cancers, with an incidence rate of approximately 0.15 newly diagnosed cases per 100,000 people/year. Thymoma patients are at higher risk of developing secondary neoplasms when compared to the general population (2,3). Patients presenting with synchronous breast cancer and mediastinal tumors represent a rare but highly challenging clinical scenario. These disorders have historically been treated with staged surgery, which frequently prioritizes one illness while delaying treatment of the other. Although this approach reduces intraoperative complexity, it may prolong overall treatment time, expose patients to multiple anesthetic events, and limit surgical planning, particularly when aesthetic preservation and reconstruction are relevant considerations. The increasing adoption of minimally invasive and robotic surgical platforms has expanded the feasibility of performing combined thoracic and extrathoracic procedures during a single operative session. Several reports have described simultaneous breast and thoracic surgery with acceptable perioperative outcomes. The literature that is currently available, however, has mostly concentrated on technical viability and safety, providing little guidance on how to coordinate multidisciplinary planning, incision location, procedural sequencing, and reconstructive timing. In this context, we report a case in which surgical planning rather than technical execution represented the key determinant of success. By integrating breast, thoracic, and reconstructive perspectives from the outset, a single-stage, minimally invasive, and scar-sparing strategy was designed. This report aims to reframe combined chest surgery as a planning-driven process, emphasizing the central role of multidisciplinary coordination in achieving oncologic radicality while preserving aesthetic outcomes. We present this article in accordance with the CARE reporting checklist (available at https://gs.amegroups.com/article/view/10.21037/gs-2026-1-0053/rc).

Case presentation

A 40-year-old woman with a significant family history of breast cancer was referred to IRCCS Regina Elena National Cancer Institute in Rome following detection of a suspicious lesion in the left breast during routine surveillance. Breast ultrasound (US) revealed an irregularly spiculated opacity in the upper inner quadrant of her left breast, specifically a hypoechoic solid lesion measuring 19 mm (Figure 1A). Mammography showed an area of parenchymal distortion between the upper quadrants of the left breast on the left which was poorly delimited (approximately 28 mm) with suspicious microcalcifications in the context and in the neighboring site (Figure 1B). The core biopsy revealed an invasive breast carcinoma with predominant non-special type G3 characteristics, featuring solid and apocrine aspects. Prognostic factors were as follows: estrogen and progesterone receptor-negative (ER⁻/PR⁻), HER2 overexpressed (3+), Ki-67 30%. On this basis, the neoplasm was overall classified as a HER2-overexpressing hormone receptor-negative breast cancer. The total body computed tomography (TCTB) scan showed a 20 mm × 15 mm × 25 mm breast mass and a 15 mm × 9 mm axillary lymph node. It also revealed an anterior mediastinal mass measuring 50 mm × 50 mm × 65 mm, which closely surrounded the main trunk of the pulmonary artery, partially involving the left brachiocephalic vein (Figure 1C). The most likely diagnosis of this second mass was thymoma.

Figure 1 Preoperative diagnostic imaging. (A) The US revealed a hypoechoic solid in the upper inner quadrant of left breast, measuring 19 mm. (B) Mammography showed an area of parenchymal distortion between the QQSS on the left which was poorly delimited (approximately 28 mm). (C) CT scan revealed an anterior mediastinal mass measuring 50 mm × 50 mm × 65 mm. CT, computed tomography; US, ultrasound; QQSS, upper quadrants of the left breast.

The clinical case was discussed by a multidisciplinary team, which recommended neoadjuvant chemotherapy followed by surgery. Additionally, our patient tested negative at screening for myasthenia gravis (MG) (anti-acetylcholinesterase antibodies) and genetic test for BRCA1/2 mutation. Following multidisciplinary discussion, neoadjuvant systemic therapy was initiated. Partial response of the breast lesion was observed, while the mediastinal mass remained stable. Unfortunately, after the second administration, she developed severe liver toxicity [G3, according to Common Terminology Criteria for Adverse Events (CTCAE) version 5] leading to the discontinuation of chemotherapy. Due to the inability to continue neoadjuvant medical therapy, following multidisciplinary discussion, surgical intervention was indicated. In view of the strong familiarity and to reduce the risk of developing a contralateral tumor, by the patient’s will, it was decided for bilateral breast surgery.

From the outset, the case was approached as a unified surgical pathway rather than as two independent oncologic problems. Early multidisciplinary coordination allowed alignment of thoracic, breast, and reconstructive strategies, with the breast surgical perspective assuming a central coordinating role due to the implications for incision placement, nipple preservation, and immediate reconstruction. The inframammary fold was selected as a single “multi-role” access site, allowing bilateral nipple-sparing mastectomy (NSM), immediate reconstruction with protheses, and robotic thymectomy to be performed within the same operative session. This approach enabled a significant reduction in the overall cutaneous trauma by limiting the number and extent of skin incisions, thereby preserving the integrity of the breast envelope and maintaining favorable conditions for reconstruction. From a technical standpoint, the inframammary incision provided adequate exposure for glandular dissection and prosthetic placement while ensuring optimal concealment of the surgical scar within a natural anatomical crease. Moreover, the use of a single access site facilitated interdisciplinary surgical coordination and improved procedural efficiency without compromising operative safety. The avoidance of additional thoracic or cervical incisions for thymectomy represented a key element in reducing cumulative surgical morbidity.

Procedural sequencing was deliberately planned. Robotic extended thymectomy was performed first to ensure oncologic control of the mediastinal disease and to protect the breast surgical field. A left sided robotic approach was chosen to preserve future breast incisions, while specimen extraction through a small subxiphoid incision allowed complete separation between thoracic and breast operative fields. This decision was central to maintaining a scar-sparing strategy (Figure 2).

Figure 2 Surgical planning and aesthetic rationale: robotic ports position on the left side and preoperative surgical markings.

Over the past two decades, the surgical management of early-stage thymoma has progressively evolved from the traditional open approach based on median sternotomy toward minimally invasive strategies. Among there, robotic-assistant thoracic surgery (RATS) has emerged as a valuable technique, expanding the possibilities of minimally invasive mediastinal surgery. The integration of three-dimensional high-definition visualization, enhanced instrument articulation, and improved surgical precision allows surgeons to perform complex dissections within confined anatomical spaces. The robotic platform provides a wide range of motion, including articulated instrument movements with multiple degrees of freedom and rotational capabilities, facilitating accurate manipulation around delicate mediastinal structures and potentially overcoming some limitations of conventional minimally invasive approaches (4,5).

NSM has become an established surgical option that combines oncologic safety with improved aesthetic outcomes in selected patients. This technique requires complete removal of the glandular breast tissue while preserving the nipple-areola complex and maintaining adequate vascularization of the skin envelope. The amount of breast tissue removes is comparable to that achieved with conventional total mastectomy (Hieken et al., 2016) (6,7). Successful NSM relies on several technical aspects, including appropriate incision planning, meticulous dissection along anatomical planes, complete excision and pathological assessment of retro areolar tissue, and careful evaluation of skin flaps to minimize the risk of residual breast tissue.

Inframammary fold or lateralizes incisions may provide adequate surgical exposure while preserving aesthetic results and reducing visible scarring. During the procedure, early separation of the breast parenchyma from the underlying pectoral and serratus muscles facilitates specimen mobilization and improved access to the superior skin envelope. This dissection is performed within the appropriate anatomical plane, preserving the integrity of the skin flap and maintaining the fibrous connections beneath the nipple until the final stage of the procedure. The retroareolar tissue is routinely submitted for histological examination to confirm the absence of malignant involvement. Preservation of the skin envelope in NSM allows immediate implant-based reconstruction, supporting a single-stage reconstructive approach.

Robotic thymectomy

The operation was performed in supine position introducing the robotic ports on the left side. First, a 1.5-cm incision was performed at VI intercostal spaces on the mid axillary line. Then, we started the CO₂-inflation with a pressure of 5–10 mmHg. The other two incisions were performed under camera vision at the VI intercostal space on the mid-clavicular line and on the anterior axillary line (Figure 2). On the right hand, we usually use a bipolar dissector while on the left hand we introduce a forceps.

The presence of a 5-cm diameter thymoma was confirmed and the standard extended thymectomy, including the thymus and the surrounding mediastinal fatty tissue, was performed. The medial dissection was initiated from the inferior aspect of the thymic tissue, in proximity to the phrenic nerve. The procedure was subsequently continued in a cranial direction along the pericardial plane until identification of the Keynes veins, which were carefully isolated and divided using a bipolar energy device. To have a totally control during the dissection and the gland veins section, the innominate vein is accurately skeletonized. The dissection was extended toward the contralateral side to guarantee the radical gland removal. Given the diameter of the thymoma, to avoid the impairment of the left mastectomy incisions, the specimen was retrieved, using an endo-bag, through an additional subxiphoid 2-centimeter (cm) access under camera vision. A 28-French (Fr) chest tube was inserted through the camera port incision at the sixth intercostal space.

Breast surgery and reconstruction

Following completion of the thoracic phase, bilateral NSM was performed through lateral inframammary fold incisions. On the left side, axillary lymph node dissection was carried out through the same access, with identification and preservation of the long thoracic nerve and subscapular pedicle. Subcutaneous mastectomy was completed bilaterally with careful flap elevation in the Cooper ligament plane.

Immediate prepectoral implant-based reconstruction was then performed using prosthetic implants, with placement of surgical drains and layered closure. The use of a shared inframammary incision enabled optimal exposure for both oncologic resection and reconstruction while ensuring excellent scar concealment and preservation of the breast envelope.

The post-operative course was regular and free from complications. The patient was discharged on the eighth postoperative day in good general and local clinical conditions.

The histopathological analysis of the surgical specimens showed the presence of a predominantly type B3 (80%) with B2 areas (20%), infiltrating the thymic capsule. Specifically, the neoplasm appeared to infiltrate the thymus and the perithymic adipose tissue. Pericardial margins were free from disease. Surgical margins were not infiltrated. No evidence of lymphovascular invasion was found. By immunophenotypic profile, neoplastic cells were CD5⁻.

Cancer pathologic stage was as follows: pathological tumor, node, metastasis (pTNM)/American Joint Committee on Cancer (AJCC): pT1a, Masaoka-Koga system IIa.

In the mammary gland, areas of fibrosis, reactive myofibroblastic proliferation, and mild chronic inflammation, including numerous macrophages, were observed, with no residual carcinoma. The 14 lymph nodes were free from neoplastic involvement. Pathological complete response (pCR): ypTx (CR-A); ypN0 (0/14).

A few weeks after surgery, the patient was administered radiation therapy, 50 Gy divided into 25 applications, in the supraclavicular region, chest wall, thymic lodge and internal mammary chain, for one month. Moreover, she continued the combined anti-HER2 therapy to reach a total year of biological therapy. Our patient was free from disease recurrence at three years follow up (Figure 3A,3B).

Figure 3 Preoperative and postoperative clinical photographs. (A) Preoperative photograph. (B) Patient’s aesthetic outcome two years after the surgery.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

Thymomas are frequently associated with autoimmune disorders, among which MG is the most prevalent. In addition, patients with thymoma have been reported to carry an increased risk of developing extrathymic malignancies. A pivotal study published in 2004 compared patients with thymoma with and without MG, demonstrating a significantly higher incidence of additional neoplasms in patients without MG, suggesting a potential protective role of autoimmune mechanisms (8).

The biological basis underlying the association between thymoma and breast cancer remains incompletely understood. Several mechanisms have been hypothesized, including genetic susceptibility, immune dysregulation, and environmental factors. From a genetic standpoint, rare reports have described thymomas harboring pathogenic BRCA mutations. Principe et al. reported an aggressive thymoma with pleural metastases in a patient carrying a deleterious BRCA2 mutation, raising the hypothesis of shared oncogenic pathways between thymic and breast malignancies (9). However, the true prevalence of BRCA mutations in thymoma remains unknown, and the role of poly (ADP-ribose) polymerase (PARP) inhibition in this setting is still investigational.

Immune dysfunction has also been proposed as a contributing factor in the development of both thymoma and extrathymic cancers, although the precise mechanisms remain largely unexplored. Environmental exposures, including prior radiation, have likewise been suggested as potential risk modifiers.

The association between thymoma and secondary malignancies has been recognized for more than five decades. Souadjian et al. first documented an increased incidence of additional neoplasms in patients with thymoma during long-term follow-up (10), a finding that has been consistently confirmed by subsequent series. Reports of multiple primary malignancies involving thymoma have since accumulated, including cases with synchronous or metachronous breast cancer (11-18).

Larger series have further reinforced this association. In a cohort of 136 patients with thymoma, Welsh et al. reported that approximately one-third developed at least one additional malignancy, with breast cancer representing one of the most frequently observed solid tumors (15). Collectively, these data support the notion that breast cancer constitutes a recurrent, albeit uncommon, concomitant malignancy in patients with thymoma.

Despite this recognized association, the optimal management of synchronous thymoma and breast cancer remains poorly defined. Most reported cases have been treated with staged surgical approaches, often driven by technical considerations or disease prioritization. While this strategy simplifies individual procedures, it may increase cumulative morbidity and preclude coordinated incision planning and immediate reconstruction.

In contrast, recent advances in minimally invasive and robotic surgery have enabled safe single-stage combined procedures. Nevertheless, the existing literature has largely focused on technical feasibility, with limited emphasis on surgical planning, procedural sequencing, and reconstructive strategy. The present case contributes to this gap by demonstrating that, in selected patients, a planning-driven, incision-sharing approach can facilitate oncologically sound, cosmetically favorable, and patient-centered single-stage surgery.

Conclusions

The simultaneous occurrence of breast cancer, the leading cancer diagnosis among women in Western countries, and thymoma, an uncommon mediastinal malignancy, has represented a unique opportunity to integrate different surgical procedures within a single robotic approach. The combination of enhanced three-dimensional visualization and increased instrument dexterity enables accurate and safe thymic dissection, offering technical advantages compared with standard thoracoscopic approaches (5).

At the same time, given the rarity of this second disease and the paucity of data on thymoma itself and its association with breast cancer, this specific case represents an almost unique model to investigate the multifactorial disease of thymoma and the pathogenesis features which may potentially connect one to the other these two neoplasms through underlying and thus far largely unexplored mechanisms.

This case suggests that an incision-sharing, robot-assisted, single-stage surgical approach may represent a feasible and cosmetically advantageous option in selected patients requiring combined breast and mediastinal procedures. In particular, it highlights the central role of planning-driven, multidisciplinary strategies in combined chest surgery, reframing such procedures primarily as a planning challenge rather than a technical one.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://gs.amegroups.com/article/view/10.21037/gs-2026-1-0053/rc

Peer Review File: Available at https://gs.amegroups.com/article/view/10.21037/gs-2026-1-0053/prf

Funding: This work was financially supported through funding from the institutional “Ricerca Corrente” granted by the Italian Ministry of Health.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-2026-1-0053/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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