Soft tissue sarcoma is a relatively rare and heterogeneous group comprising malignant neoplasms.
The international scientific and medical community are studying the molecular and cytogenetic pathways that connect the pathogenesis of different types of sarcoma; this research can be used to develop drugs.
Because sarcoma is a rare cancer and each type behaves differently, there is limited research on it, and drug development is taking longer than usual.
At the moment, we have a general understanding of the disease and how it impacts the body.
The soft tissue tumor originates from mesenchymal tissues and is also called mesenchymal neoplasia. Any tissue originating from the mesenchyme may differ in neoplasia, vary in the clinical form of presentation, location, and histopathological findings.
Each case of sarcoma is unique; the medical team treats every case differently. Surgical procedures should only be performed after studying the patient’s case extensively.
Tumors that grow in the pelvic region (uterine leiomyosarcoma, chondrosarcoma, osteosarcoma, etc.) may only present symptoms after the lesion has grown to a significant size.
Osteosarcoma in the pelvic region is curable if detected early.
Bone sarcomas often affect the adjacent soft tissues, but soft tissue will rarely invade the bone. The vast majority of these soft tissue tumors occur in the deep fascia. Studies show that the prognosis and lesions that ulcerated are in worse condition when the tumor invades the fascia.
According to studies, less than 1% of all cancers are caused by sarcomas. These aren’t as common as malignancies, but in absolute numbers, there are a sufficient amount of cases. Sarcoma cancer usually occurs in adulthood; only 15% of cases appear in childhood or adolescence.
The definitive diagnosis of these lesions is made through biopsy and anatomopathological study; the biopsy can be performed percutaneously or openly.
The aggressive lesions of high-grade soft tissue sarcoma can be diagnosed using a combination of clinical history, physical examination, and images; however, a biopsy is necessary to understand histogenesis.
The treatment of these injuries involves a multidisciplinary team that moderates the disease’s local and systemic management.
Regarding local control, studies show that only 15% will have a recurrence. The tumor remerges for several reasons; these include the surgical margin (if the lesion was completely removed and a “cover” was placed on it), the size of the tumor, whether it’s a recurrent lesion, and the disease’s behavior.
Literature shows elderly patients are more prone to relapse of sarcoma. Radiotherapy is a fundamental part of treatment and can be done before or after surgery, depending on the injury, the medical team’s expertise, and other related factors.
Chemotherapy will be recommended for patients with large deep fascia tumors since they have a greater chance of survival.
The disease spreads via the hematogenous route; the majority of lesions are found in the lungs at a distance from soft tissue sarcoma.
Metastasis to visceral tissues and bone is rare, but it can occur in some types of sarcoma. Although it isn’t as common, lifonodal involvement can also occur and is related to specific types of soft tissue tumors, including clear cell sarcoma, epithelioid sarcoma, synovial sarcoma, and epithelioid sarcoma.
In general terms, the staging (screening) of soft tissue sarcoma is performed with radiographic and resonance images of the lesion site and a chest tomography. Since lymph node metastasis is extremely rare, PET-CT still does not have a well-defined role in the mesenchymal tumor.
Sarcoma can be cured in cases that are diagnosed early and treated on time.
Let’s take a look at the various forms of sarcoma, including fibrosarcoma, liposarcoma, and others.
There’s a general rule in the world of oncology that states, “Any suspicious tumor in the extremities must be treated as a sarcoma until proven otherwise.”
The recommended treatment is based on the histological degree of the lesion, its location, the presence/absence of metastatic disease, and also on the patient’s own psycho-social factors.
Some lesions make oncologists wary about the presence of being a malignant neoplasm; any tumor that is more than 5 cm or deep in the fascia should cause concern and be investigated further.
We offer complimentary exams as part of the investigative procedure. We assess other parts of the body associated with the injury site, for example, a resonance of the leg or ankle, depending on the location of the tumor in the leg.
Ultrasounds are used to guide the medical team during biopsies. Tomography doesn’t play a role in the diagnosis of the lesion, but it does in staging, where we assess whether there is metastasis in the lungs.
Some specific types of soft tissue tumors lead to abdominal or pelvic distant organ metastasis. It’s important to assess the lymph node involvement for certain types of sarcoma such as synovial, epithelioid, angiosarcoma, rhabdomyosarcoma, and clear cells.
To date, there is no clinical role for PET – CT for the staging of sarcomas.
The main objective of surgery is to remove the disease locally. The supporting ongoing treatment should increase the chance of survival and maximize residual motor function.
Surgery also plays an important role in the diagnosis of the lesion, as the tumor is often large and the biopsy can only detect a part of the lesion.
Let’s talk a little bit about the types of surgery that are performed in cancer patients.
Enneking defined intra-lesional, marginal, wide (margin used for the resection of a sarcoma) and radical surgeries for sarcoma cancers.
Intra-lesional resection is not used for malignant tumors; as there will be an incomplete resection, neoplasic cells will be left behind.
Marginal resection is one procedure in which we resect a tumor by its pseucapsule; this is where neoplastic cells are usually located. Radical resection is needed when the surgical objective is to remove all the compartments involved in the injury.
1- Undifferentiated Pleomorphic Sarcoma
Initially, the term malignant fibrous histiocytoma was used to describe the pleomorphic sarcomas that appear in adults.
The molecular characteristics of these tumors vary widely, with some showing positivity for lipomatous markers. This undifferentiated malignancy affects mainly men and patients over 50 years of age.
Fusocellular sarcoma of this type tends to appear in the proximal region of the extremities (its less frequent form of sarcoma that occurs in the leg), preferably in the lower limb.
On resonance, it will appear as a solid lesion with a heterogeneous characteristic. This tumor presents as histopathological characteristics, a great cellular pleomorphism and aggressive mitotic activity,
2- Lipomatous Sarcoma
Well-differentiated liposarcomas, also called atypical fatty tumors, have slow growth, and don’t have a high risk for metastasis. They are typically treated with surgeries without adjuvant (chemotherapy or radiotherapy). This may manifest as a lump in the leg and thigh.
This type of sarcoma is treatable.
3- Myxoid sarcoma
The prognosis of this lesion is worse when small round cells are present. Soft tissue ultrasonography isn’t used to study the soft tissue tumor. This is a type of tumor that can cause metastases in regions other than the lung.
The medical team will examine the abdominal and pelvic region with a computed tomography to check for metastases. Studies show that this form of sarcoma responds better to chemotherapy and radiation.
4- Dedifferentiated Liposarcoma
This lesion usually occurs over a previous liposarcoma as a focus of de-differentiation that can be seen on resonance by the presence of a heterogeneous area in an area surrounded by low-grade lipomatous tissue.
5- Pleomorphic Liposarcoma
This soft tissue sarcoma is a type of de-differentiated liposarcoma that occurs in less than 5% of liposarcoma cases.
It occurs in patients over 60 years of age. Unlike the malignant tumor in the leg that we notice more easily, those that are deep in the pelvis can only be diagnosed at later stages.
Cancer sarcoma of this histology is difficult to diagnose because of lipoblastic differentiation; it is difficult to find this in the anatomy of larger surgical specimens. This etiology has no genetic or molecular characteristics that identify it.
6- Synovial Sarcoma
Synovial sarcoma usually manifests with a monophasic or biphasic architecture with epithelioid or spindle cells. This sarcoma tumor has similar behavioral characteristics as epithelial sarcomas. Its mesenchymal neoplasm whose cytogenetic profile helps in the diagnosis since the t (X; 18) translocation (p11.2; 11.2) is characteristic and appears in most cases.
The SYT-SSX1 and SYT-SSX2 rearrangement makes it easy to identify. The synovial name was given due to the microscopic aspect resembling mature synovial tissue, but its cellular origin is still uncertain.
These tumors are usually just articular and will rarely be seen within the joint. This cancer sarcoma can present itself in several ways; it can appear with rapid and aggressive growth or even small and indolent size.
Synovial sarcoma is known to share similar characteristics with soft tissue sarcoma and responds well to chemotherapy. The systemic adjuvant treatment is dependent on the center where it is treated and other issues related to the disease itself, such as the size of the lesion, how deep it is located, the degree, the age of the patient, the presence/absence of metastatic disease, and comorbidities.
7- Clear cells
Clear cells are also known as a mesenchymal neoplasm called soft tissue malignant melanoma. It has an immunohistochemical characteristic of positivity for HMB-45 (which is a marker of melanoma).
In these cases of sarcoma, the translocation t (11; 22) (p13; q12) occurs, in addition to expressing the anti-apoptotic Bcl-2. Clear cells have a potential for lymphatic dissemination. It can manifest as sarcoma in the leg.
Like synovial sarcoma, it can be present for many years without significant cancerous growth.
The soft tissue sarcoma is called angiosarcoma and normally occurs in elderly patients (above 60 years). Unlike other soft tissue tumors, it usually occurs on the outer regions in the form appearing as skin lesions.
Angiosarcomas can be varying severities; high-grade ones being more common. Like in mesenchymal neoplasia, this sarcoma has a positive vimentin in histology, and many of them are positive for vascular markers.
This fusocellular sarcoma has an aggressive behavior with a history of local recurrences and lung metastases. Chemotherapy is not effective in such cases.
9- Kaposi’s Sarcoma
Kaposi is an endothelial vascular lesion and presents in many ways. Some forms are associated with the HIV virus. Kaposi’s sarcoma is an African endemic, it’s iatrogenic, and HIV-related.
Its treatment depends on the location of the injury and the extent of the disease. Treatment may include surgery, radiotherapy, and chemotherapy.
10- Epithelial Sarcoma
Epithelial type soft tissue sarcoma is the sarcoma of the hand. Like the synovial, this lesion has an indolent characteristic and can grow very slowly. It’s often confused with benign lesions such as fibromatosis or a benign mesenchymal tumor.
These commonly occur in a patient under 40 years of age, despite its slow growth, it has a high potential for recurrences and lung metastasis. It also tends to spread to lymph nodes.
Among all types of sarcoma, the epithelioid can benefit from a sentinel lymph node study.
11- Dermatofibrosarcoma Protuberans
This is a low-grade mesenchymal neoplasm that usually occurs in young adults. This sarcoma cancer can take months or years to grow before the patient experiences discomfort.
Surgical treatment is a wide resection; patients may require plastic surgery to cover sarcoma.
12- Ewing’s Sarcoma
This lesion is rare in the form of extraskeletal presentation. Ewing’s Sarcoma that occur in the leg are more common. Unlike most soft tissue sarcomas, this is considered chemosensitive; the medical team will recommend and high doses of chemotherapy. Its treatment includes radiotherapy and extensive surgery.
13- Extraskeletal Osteosarcoma
These lesions occur more frequently in older patients (adults). It’s most common in the lower limb. Histologically, there is the presence of an osteoid matrix.
The prognosis of this fusocellular sarcoma is unfortunate, since the affected patients are in older age groups; such patients aren’t good candidates for chemotherapy.
14- Extraskeletal Myxoid Chondrosarcoma
This lesion is extremely rare among high-grade soft tissue sarcomas. It usually appears in seniors.
Like cartilaginous tumors, it may look like calcifications on the radiograph.
This type of sarcoma grows very slowly; it can take years before the tumor is diagnosed. The cytogenetic evaluation demonstrates two characteristics of translocations t (9; 22) (q22; q12) and (9; 17) (q22; 11). In terms of survival, we can say that this mesemquimal neoplasm has a good prognosis in the 5-year follow-up.
15- Alveolar Sarcoma of Soft Tissues
This tumor appears in patients under the age of 30; it’s usually found in the lower limbs as the thigh or as a nodule in the leg.
It’s more prominent in male patients. His histopathology demonstrates an alveolar architecture that can sometimes confuse the pathologist who studies the case, leading to a diagnosis of alveolar rhabdomyosarcoma.
This sarcoma differs somewhat from clinical and histological behavior when compared to others, as it is extremely aggressive. It doesn’t show signs of mitosis and pleomorphism of the nucleus. The cytogenetic change that is seen most frequently is at (x; 17) (p11; q25).
Leiomyosarcoma can be identified by gynecologists as it appears in uterine leiomyosarcoma.
The vast majority of these lesions appear in the retroperitoneal region and the abdomen. In severe cases, they appear on the wall of a major vein in the body.
Histopathological diagnosis is relatively simple since this tumor group presents clear symptoms.
17- Sarcomas of the Nervous Tissue
It is a mesenchymal neoplasm of the soft tissue tumor group. This type of sarcoma is more routinely called neuro fibrosarcoma. It manifests in patients with multiple neurofibromas.
Despite being a benign lesion, the tumor can be quite aggressive. The efforts of large centers have focused on PET-CT for the screening of these patients.
The survival rate of these patients is around 30-40% in the first 5 years. These lesions are in the histopathological study, positive for the S-100 protein, and do not demonstrate cytogenetic abnormalities.