Myxofibrosarcoma is a rare soft tissue cancer, or sarcoma, that arises from the body’s connective tissues. These tissues connect, support, and surround other body structures, such as fat, muscle, and skin. This cancer is most frequently diagnosed in older adults, between the ages of 50 and 80, and develops more often in men. While it can appear in various parts of the body, it is most commonly found in the limbs, particularly the legs.
Understanding Myxofibrosarcoma
Myxofibrosarcoma originates in fibroblastic cells, which are responsible for creating the fibrous connective tissue that gives structure to the body. The tumor’s name describes its microscopic appearance; “myxo” refers to its gelatinous or mucus-like stroma, while “fibro” points to the fibrous, spindle-shaped cells it contains. This composition gives the tumor a distinct, nodular texture. These tumors are known for their infiltrative growth pattern, meaning they grow into surrounding healthy tissues, which can make complete removal challenging.
A primary aspect of myxofibrosarcoma is its grade, determined by a pathologist examining the tumor tissue under a microscope. The grade reflects how abnormal the cancer cells appear and how quickly they are dividing. Myxofibrosarcomas are classified as low, intermediate, or high-grade. Low-grade tumors grow slowly, while high-grade tumors grow rapidly and are more likely to spread to distant parts of the body, a process known as metastasis. This grading is a primary factor medical teams use to predict the tumor’s behavior and plan treatment.
Common Signs and Symptoms
The most frequent initial sign of myxofibrosarcoma is the appearance of a lump or mass under the skin. This mass often grows slowly over time and is typically painless, which can lead to delays in seeking a medical evaluation. The lump itself may feel soft and mobile upon physical examination.
In some cases, the tumor can cause symptoms beyond a visible mass. If the growth presses on nearby nerves or muscles, it can lead to pain, tenderness, or swelling in the affected area. The specific symptoms depend on the tumor’s size and location. Because the initial presentation can be subtle, any new or growing lump should be evaluated by a healthcare professional.
The Diagnostic Journey
Confirming a diagnosis of myxofibrosarcoma involves a multi-step process that begins with a physical examination. A doctor will assess the lump, noting its size and feel, and inquire about its history. Because myxofibrosarcoma can resemble other conditions, including noncancerous growths, this initial step is just the start of the diagnostic path.
To get a clearer picture of the mass, imaging tests are employed. Magnetic Resonance Imaging (MRI) is the most common and effective tool, as it provides detailed images of soft tissues. An MRI helps determine the tumor’s size, its location relative to other structures, and can reveal features like an infiltrative border. A Computed Tomography (CT) scan may also be used to check if the cancer has spread to other areas of the body, such as the lungs.
The definitive step in diagnosis is a biopsy. During this procedure, a small sample of tissue is removed from the tumor, often using a needle guided by imaging. This tissue sample is sent to a pathologist who examines the cells under a microscope. This analysis confirms the presence of cancer, identifies it as myxofibrosarcoma, and determines its grade, which is foundational for planning treatment.
Primary Treatment Modalities
The main treatment for myxofibrosarcoma is surgery to remove the tumor. The surgeon’s objective is a “wide local excision,” which involves removing the cancerous mass along with a surrounding margin of healthy tissue. Achieving these clear margins is important because of the tumor’s tendency to infiltrate nearby tissues. In most cases, surgeons perform limb-sparing surgery to remove the cancer while preserving the function of the arm or leg.
Radiation therapy is frequently used in combination with surgery. It can be administered before surgery (neoadjuvant therapy) to shrink the tumor and make it easier to remove. Alternatively, it can be used after surgery (adjuvant therapy) to destroy any cancer cells that may have remained. The use of radiation reduces the chances of the tumor returning in the same location.
Chemotherapy is not a standard initial treatment for localized myxofibrosarcoma. Its use is reserved for specific situations, such as for tumors that are high-grade, very large, or if the cancer has metastasized. For advanced disease, chemotherapy drugs may be used to control the cancer’s growth.
Recurrence and Long-Term Outlook
Myxofibrosarcoma has a notable tendency to recur locally, meaning it can grow back in the same area where it was first removed. Local recurrence rates range from 16% to over 50% of cases within five years. This high potential for recurrence highlights the importance of the initial surgery and adjuvant radiation. When a tumor does recur, it sometimes comes back as a higher-grade, more aggressive cancer.
Given the risk of recurrence and spread, long-term monitoring is a standard part of post-treatment care. Follow-up appointments include regular physical exams and imaging scans, such as MRIs of the original tumor site and CT scans of the chest. This surveillance allows doctors to detect any new tumor growth as early as possible.
The long-term prognosis for an individual with myxofibrosarcoma depends on several factors. These include the tumor’s grade, size, depth, and whether the surgeon was able to remove it with clean margins. Smaller, lower-grade tumors that are completely removed have a more favorable prognosis.