Mandibular Myxoid Liposarcoma: a Case Study

Abstract

Liposarcomas are described as soft tissue sarcomas derived from adipose tissue. The finding of this tumor in the mandibular region is exceedingly rare. As of now, it has been described mainly in case reports and small series. A multidisciplinary approach is required to offer optimal treatment and may involve surgery, radiation and systemic therapies. Surgical repair of these defects represents a major challenge in oral and maxillofacial reconstructive surgery. We present the case of a 54-year-old man referred to our center with a progressively increasing mass in the anterior portion of the mandible. Biopsy revealed a well-differentiated myxoid liposarcoma. Resection of the tumor was performed with an additional primary reconstruction.

Introduction

Liposarcomas are the most prevalent soft tissue sarcomas, accounting for 20% of all malignant mesenchymal neoplasms [1]. These are commonly described as a mesenchymal malignancy characterized by adipocyte differentiation and are classified as atypical lipomatous tumor/well-differentiated, dedifferentiated liposarcoma, pleomorphic liposarcoma and myxoid liposarcoma [2]. The mandibular location of this tumor is uncommon and scarcely reported in the literature. We report a case of a 54-year-old male with an anterior mandibular myxoid liposarcoma, who underwent complete tumor resection and primary reconstruction of the mandible using a non-vascularized fibular graft and a pectoralis major flap.

Case Report

A 54-year-old man former smoker was referred to our center with a 2-year history of a mandibular mass with progressive growth, eventually leading to odynophagia and dysphagia. Physical examination revealed a 12 × 10 × 5 cm grey-tan solid mass, located predominantly on the inferior labial vestibule (Fig. 1A). Laboratory results were unremarkable. A cervical computer tomography (CT) scan showed a mandibular infiltrating mass with diffuse cystic components and clear extension to the sublingual space. A biopsy was performed and confirmed the diagnosis of well-differentiated myxoid liposarcoma.

Fig. 1.

A Solid mass in the anterior portion of the mandible (arrow). B Mandibular reconstruction plate mounted to fibular allograft (white arrow) and pectoralis major flap (yellow arrow). C Patient after the reconstructive procedure

The patient underwent elective surgery. In the operating theatre, the tumor was resected by incising at the level of the mandibular symphysis and dissecting the local anatomical planes until reaching the bone. At this point, a mandibulectomy was performed leaving 1.5 cm of lateral margins at both ends to successfully resect the entire lesion, obtaining a 300 g complex. Pathological examination was consistent with a well-differentiated myxoid liposarcoma with negative surgical margins. Subsequent immunohistochemical studies reported positivity for S-100, CD34 and type IV collagen.

After resection of the tumor, a mandibular reconstruction was performed. For this purpose, a mandibular plate was molded preserving the pre-established oral occlusion of the patient. Subsequently, an autogenous non-vascular fibular graft was used to create a new mandibular arch, with the aid of 2.4-mm monocortical screws. This was followed using a pectoral flap to reconstruct the floor of the mouth as well as the lower labial vestibule. Finally, an oral mucosalplasty with 4-0 vicryl was achieved in conjunction with a gentle subdermal closure of the labial skin with 5-0 nylon (Fig. 1B, C). The patient was discharged without further complications.

Discussion

Myxoid liposarcoma is known as the second most common subtype representing 15–20% of all liposarcomas [2]. They harbor a translocation involving genes FUS-DDIT3 or EWSR1-DDTT3 and occur mostly in patients between the ages of 35 and 55 [3]. The maxillofacial location of these tumors is rare. It is often described clinically as a deep tumor located in the lower extremities with the potential to metastasize to non-pulmonary soft tissues such as the retroperitoneum, bone or contralateral extremity [4].

Immunohistochemistry, among ancillary tests, is useful to complement the diagnosis. Myxoid liposarcoma often shows immunoreactivity for the S-100 protein [5]. Similarly, CD34, known as human hematopoietic progenitor cell antigen, which is also established as a marker for other non-hematopoietic cell types, has been reported to be expressed in well-differentiated, dedifferentiated liposarcomas and in the myxoid spectrum [6–8].

Treatment of this condition involves surgery, radiation and systemic therapies. Surgical excision with or without radiation therapy remains the treatment of choice for the localized presentation [2], with an almost null rate of metastasis and excellent survival rate [9].

Mandible reconstruction is recommended early after diagnosis, as it provides faster rehabilitation and less morbidity [10]. Bone and soft tissue reconstruction can be achieved using non-vascularized grafts or free vascularized bone flaps. The latter has become the technique of choice for structural and functional reconstruction; however, there are some associated risks that depend mainly on the microsurgical technique when performing arterial and venous anastomoses. In addition, about 20% tend to fracture as a late postoperative complication [11].

Microvascular tissue transfer is now considered the gold standard as it has played a key role in complex oral and maxillofacial reconstructions. However, in circumstances where it is not possible to provide it a mandibular plate with a non-vascular bone graft, and pedicled flaps, such as the pectoralis major myocutaneous flap or the submental island flap are possible alternatives to approach the structural reconstruction [12, 13].

Myxoid liposarcomas are characterized by having a low local and distal rate of recurrence and are much more radiosensitive than many other types of soft tissue tumors. The decision to administer adjuvant chemotherapy is based on the risk of recurrence with metastatic disease [14]. Avoiding inadequate excision of surgical margins is critical to minimize the possibility of local recurrence and consequently the risk of metastasis, as well as reducing additional interventions that increase the likelihood of compromising the maxillofacial reconstruction. In the metastatic setting, confined to a single organ or with limited tumor bulk, metastasectomy with a combination of neoadjuvant or adjuvant systemic therapy with or without the addition of radiotherapy is among the treatment options.

Declarations

Consent to Participate

Written, informed consent was taken from the patient.

Conflict of Interest

The authors declare no competing interests.