International Seminars in Surgical Oncology BioMed Central

Background: Superficial leiomyosarcoma is an exceedingly uncommon malignant tumor which could be located either to cutaneous or subcutaneous tissues. Increased mass size and depth, advanced tumor staging and inadequate surgical excision are the main prognostic factors for poor result.


Background
Superficial Leiomyosarcoma (LMS) is a quite uncommon tumor which is mainly developed in the proximal portion of the lower limbs [1][2][3]. The lesion can be appeared as a single nodular mass or multiple swelling tumours [2,4]. Although it may occur in any age, superficial LMS is more prevalent between the fifth and seventh decade of life. Furthermore, a male predominance with a male-to-female ratio of 2:1 was also described [1,2]. The tumor could be located either cutaneously or subcutaneously. In the first case, it is arisen from the limb extensor surfaces where a greater density of hair structures (arrectores pilorum muscles) exists [1,2,5]. It is frequently quite small-less 2 cmcausing local changes like skin discoloration, umblication and ulceration [1,2].
We report a rare case of a giant subcutaneous LMS of the proximal tibia. Wide excision of the tumour in combination with local RTP and systemic CTP led to good functional outcome and no recurrence until the latest follow up (3 yrs postoperatively).

Case presentation
A 71-year-old man, without medical history, referred to Tumor Outpatient Clinic of the Hospital due to an extensive exophytic mass of the anterior-medial side of the right proximal tibia. The lesion was appeared ulcerated and bloody with irregular areas of necrosis and haemorrhage and its size was 12 × 10 cm with collar of around 10 cm. (Figure 1). The patient reported that the mass was completely asymptomatic and its growth was slow. He wasn't worried about its nature until an innocuous trauma caused ulceration at tumor site 2 weeks ago. Plane X-Rays showed a radiolucent lesion adjacent to the anteriormedial side of the proximal tibia without cortical disruption or continuity with the bone (Figure 2). Magnetic Resonance Imaging (MRI) confirmed the suprafascial character and extension of the lesion and revealed no clear relationship with the surrounding muscles and bone (Figure 3). The previously performed open biopsy couldn't clarify the true nature of the lesion as the described diagnosis was "unspecified soft tissue sarcoma". According to the above findings and after patient's referral, new samples were received and histologic examination showed a soft tissue leiomyosarcoma. Subsequent Computed Tomography (CT) scans of chest and abdomen and total bone scan excluded the presence of systemic lesions or metastasis and the patient was scheduled to undergo surgical resection of the lesion with additional removal of a sleeve of surrounding tissues.
Under general anaesthesia and tourniquet application, en block wide excision of the mass was performed. As the Anteroposterior (A) and Lateral (B) X-Ray view of the right knee Figure 2 Anteroposterior (A) and Lateral (B) X-Ray view of the right knee. A soft tissue mass in the anterior-medial side of the proximal tibia with no evident continuity with the bone or cortical invasion was apparent.
Macroscopic appearance of the exophytic mass in the ante-rior-medial side of the right leg Figure 1 Macroscopic appearance of the exophytic mass in the anterior-medial side of the right leg. The mass showed nodular growth pattern and the cut surfaces were ulcerated and bloody with irregular areas of necrosis.
tumor was very close to the bone, a portion of the anterior-medial cortex of the proximal metaphysis of the tibia was also removed to facilitate at least 2 cm resection margins circumferentially (Figure 4). After tumor excision, a large skin and soft tissue defect was remained and transplantation of gastrocnemius myocutaneous flap was deemed necessary for covering the defect ( Figure 5). At the end of the procedure, the tourniquet was released and the vascular integrity of the flap and limb was evaluated.
At histological analysis, multiple elongated cells of mesenchymal origin surrounded by myofibrils and many polygonal epithelioid cells with evident pleiomorphism and elevated mitotic index were found. The surgical margins were free of disease and some necrotic areas were recognised as well. The positive immunohistochemical staining for smooth muscular actin, vimentin and caldesmon led to diagnosis of grade III LMS according to the grading scale modified from Broders et al. and Angervall et al. [16,17] (Figure 6).
The postoperative course was uneventful and no local or systemic complications were encountered. Due to the weakening of the proximal tibia from the excision of the anterior-medial cortex, partial weight bearing for 6 weeks was advised. After wound healing the patient was submitted to the Oncology Department for local RTP and systemic CTP.
At the latest follow up visit (3 years) clinical and laboratory examination (X-Rays, MRI, Bone Scan) didn't reveal any signs of tumor recurrence or metastasis. The patient could stand and walk without any restriction and he was able to perform his usual daily activities.

Discussion
The distinction between cutaneous and subcutaneous LMS is of primary importance for prognostic reasons [2,8,10]. Although the cutaneous LMSs are associated with local recurrence in about 30-50% of cases only a low incidence of 0-10% of metastasis has been described [1,2,15,18]. On the other hand, subcutaneous LMSs may develop local recurrence in about 40-60% of patients and distant metastasis in 20 to 60% of patients [1,2,5,8,10,12,15]. As a result, the mortality may be raised up to 30-40% [2,18]. Despite the fact that tumor location and depth affect the recurrence rate and metastatic risk, the mitotic activity seems not to have a similar effect [1,2,8].
In the current patient, the size of the tumor (12 × 10 cm) was higher than the previously reported cases. Specifically, the mean size reported in literature for superficial LMSs is about 5 cm, with a wide range from 0.5 to 19 cm [2,4,8,19]. Some authors described cases of LMSs with larger size (up to 35 cm), but in their series they didn't distinguish the superficial soft tissue LMSs from non-visceral deep LMSs [15,20]. Large tumors (>5 cm) are considered Axial (A) and Coronal (B) MRI T1-weighted image of the right proximal tibia Figure 3 Axial (A) and Coronal (B) MRI T1-weighted image of the right proximal tibia. A large homogeneous mass which was invaded the adjacent soft tissue and extended along the medial surface of cutaneous plane was visible. No signs of bone tissue infiltration, or abnormal intensity in muscle tissues could be seen.
to have worst prognosis in terms of recurrence and metastasis [1,8,[12][13][14][15]. In a multivariate analysis of 267 patients with leiomyosarcoma, Miyajima et al. found that tumour size and advanced staging were the only factors that were correlated independently with decreased survival [20].
Wide excision of the lesion is of outmost importance as it is strongly correlated with disease-free survival [1,2,8,10,[12][13][14][15]. Massi et al. in a retrospective study of 62 patients with extremity soft tissue leiomyosarcoma reported that seven out of the nine patients who had developed one or more local recurrences had been surgically treated with either marginal or intralesional excision [13]. Similarly, Svarvar et al. in a large study of 225 patients with leiomyosarcoma which was based on Scandinavian Sarcoma Group Register showed that the inadequate local treatment was the main risk factor for local recurrence [15].
Many authors have been supported the application of postoperative RTP and CTP in high grade LMSs [1,2,10,[12][13][14][15]. However, the role of adjuvant therapy in LMSs is still controversial as no sufficient statistical evidence exists regarding their efficacy. The above treatment modalities may have a higher impact on local and systemic tumor respond when adequate excision of large and high grade lesions could not be achieved [13][14][15].

Conclusion
Even though delayed diagnosis and giant size of soft tissue leioymyosarcomas may adversely affect the final result, successful recovery could be anticipated. Special focus should be given to careful and meticulous wide excision of the mass as the role of chemotherapy and radiotherapy is still blur and unknown.
Macroscopical post-operative aspect of patient's leg