What is Epithelioid Sarcoma?
This is a rare type of cancer, which starts from the connective tissue and spreads through different parts of the body. Its name is related to the epithelioid features that are characteristic for this particular type of soft tissue sarcoma. Less than 1% of the general population is diagnosed with this condition, which makes it a rare disease. The condition was described in the 1970s and today it is known that it affects primarily the extremities. It is often seen in young adults and may affect the genital area or the spine in rare cases.
These are the most common symptoms of epithelioid sarcoma:
- Small and soft mass
- May also appear as a series of bumps on the skin
- Most common location – distal extremities (fingers, hands, forearms, feet)
- The mass is hard and firm to the touch (location – dermis/deep soft tissue)
- If the lesion is superficial, it may also ulcerate
- Pain or tenderness (20% of the patients)
- Muscular weakness and numbness – these appear due to the compression of the nerves, caused in their own turn by the hand tumors
- Metastases – most common: lymph nodes, lung and scalp
These are the clinical features of epithelioid sarcoma:
- Most frequent location – hands and forearms
- Other possible locations include: distal lower extremities, proximal upper extremities
- The mass present on the skin might mimic a wart or a wound that is healing poorly (often misdiagnosed)
- If the tumor has a deep location, it might be confused with a ganglion cyst; also, if it has become attached to the muscle tendon, it might be taken for a giant cell tumor of the tendon sheath
- Multifocal tumors – 13% of the patients
- Metastatic disease – 13% of the patients (lymph nodes, scalp, lungs – most common sites)
- Hand tumors can also appear as a clinical feature of the epithelioid sarcoma
These are the most common methods used for the diagnosis of the epithelioid sarcoma:
- Tissue biopsy – most often chosen for the confirmation of the diagnosis
- Sentinel lymph node biopsy – this is often recommended, as it is known that the epithelioid sarcoma often involves the lymph nodes
- Immunohistochemical staining – can be useful in identifying the genes that have lost their function (thus making the diagnosis of epithelioid sarcoma)
- MRI – this investigation allows the doctors to identify the exact location of the sarcoma masses, this being the primary reason why it is performed ahead of the tissue biopsy and the pathologic analysis. The MRI can also be useful after the surgical intervention, so as to determine if the tumor has recurred.
These are the preferred methods of treatment for epithelioid sarcoma:
- Surgical intervention
- Wide surgical resection
- The rate of recurrence is high if only marginal resection is performed
- The risks of the wide surgical resection are related to the patient losing some of his/her abilities (dysfunction) and also to the associated morbidity
- Amputation – recommended in patients who present multiple recurrences or if the tumor is located in a part of the body that can be removed without influencing too much of the functionality (such as the tip of the finger)
- Sentinel node biopsy and regional lymph node dissection
- Recommended due to the involvement of the lymph nodes
- Recommended choice – doxorubicin
- The treatment with chemotherapy is indicated for patients who have been diagnosed with multifocal tumors or those who have reached the stage of metastatic disease
- Radiation therapy
- Recommended for both primary and recurrent tumors
- May guarantee the salvaging of the affected limb, especially in comparison to the other alternatives (amputation)
- Does not prolong the patient’s existence
- The functionality can become impaired, due to the long-term radiation therapy, as this leads to rigidity, scarring and even neuropathy in the respective limb
According to the latest studies, the 5-year survival rate in patients diagnosed with epithelioid sarcoma varies between 50-70%. On the other hand, the 10-year survival rate in the same patients is of 42-55%. There are numerous factors that can have a definite influence on the survival rate, including the age of the patient, the gender, the localization of the tumors and the dimensions of the tumors. The histopathologic changes that occurs with the epithelioid sarcoma are going to influence the survival rate as well.
In terms of prognosis, it has been demonstrated that gender plays an essential role. Women have been identified to have a better prognosis than men, which suggests that the survival rate is influenced by gender. Apart from that, it seems that the patients who present proximal lesions have a more negative outcome than those who present distal lesions. The age seems to have an influence on the prognosis as well. For example, the younger the age of the patient, the better the outcome will be.
A negative prognosis is also considered in the patients who presents tumors that are larger in size (over 2 cm diameter). If the tumor has also become affected by necrosis or if the doctor observes vascular invasion in the respective patient, then the outcome is negative as well. In deciding on the prognosis for the epithelioid sarcoma, the doctors will also take into consideration the mitotic index.
In conclusion, this is a rare type of sarcoma, which affects primarily young adults. The lesions are predominantly found on the upper extremities, especially on the hand and forearm. At first, a single mass might be present, being painless and growing quite slowly. However, there are a lot of patients that present multifocal tumors and metastatic disease, with the progression of the condition. Despite the invasive treatments, the condition has a high tendency of recurrence and it often involves the lymph nodes. The most common method of diagnosis is the tissue biopsy but the sentinel node biopsy is also performed, especially if there is a suspicion of lymph node involvement. Genetic testing might guarantee a better diagnosis in the future, eliminating the risk of this condition being misdiagnosed. The most common treatment is represented by the wide resection. Risk factors that lead to a negative prognosis include gender (males are more predisposed to a negative outcome than women), tumor size and vascular invasion.