The Function of Soft Tissues and Complications Associated with Soft Tissue Tumors
Soft tissues include muscles, tendons, ligaments, fat, blood vessels, lymphatic vessels, and connective tissue that support, connect, and surround various structures and organs throughout the body. These tissues play vital roles in mobility, cushioning of organs, vascular and lymphatic transport, and structural integrity. Tumors in these areas—whether benign or malignant—can severely disrupt these functions, leading to pain, restricted movement, swelling, vascular compromise, or compression of vital structures.

Soft tissue tumors arise from mesenchymal tissues and may be either benign (non-cancerous) or malignant (cancerous). Malignant soft tissue tumors are known as soft tissue sarcomas. These cancers can develop anywhere in the body but are most common in the limbs and retroperitoneum. Although rare compared to other cancers, they are complex and require multidisciplinary care due to their diverse subtypes and unpredictable behavior.

Categories Associated With Primary and Secondary Soft Tissue Tumors

Primary Soft Tissue Tumors
These originate directly from the soft tissues. They are categorized based on the tissue they resemble histologically:

• Benign Tumors: Lipomas, hemangiomas, fibromas, leiomyomas

• Malignant Tumors (Soft Tissue Sarcomas):

  • Liposarcoma (fat cells)

  • Leiomyosarcoma (smooth muscle)

  • Rhabdomyosarcoma (skeletal muscle, common in children)

  • Fibrosarcoma (fibrous tissue)

  • Angiosarcoma (vessels)

  • Synovial sarcoma (around joints)

  • Undifferentiated pleomorphic sarcoma (UPS)

Secondary (Metastatic) Tumors to Soft Tissues
Metastases to soft tissues are uncommon but may occur from cancers such as lung, kidney, breast, or colon. Their presence usually signifies advanced-stage disease.

Causes and Risk Factors

Soft tissue tumors have no single identifiable cause, but certain risk factors include:

• Genetic predispositions: Li-Fraumeni syndrome, Neurofibromatosis type 1, Retinoblastoma

• Radiation exposure: Prior radiotherapy is a known risk for secondary sarcomas

• Chemical exposures: Vinyl chloride, arsenic, or herbicides

• Chronic lymphedema (Stewart-Treves syndrome)

• Injury or trauma: Not causative but may lead to detection of preexisting tumors

Signs and Symptoms of Soft Tissue Tumors

Symptoms often depend on tumor size and location. Early tumors may go unnoticed. Common presentations include:

• A painless, enlarging lump (most common sign)

• Pain or tenderness if nerves or blood vessels are compressed

• Swelling or limited range of motion if near joints

• Neurological symptoms (numbness, tingling) if a nerve is involved

• Fatigue, weight loss (in advanced or metastatic disease)

Diagnosis of Soft Tissue Tumors

1. Medical History & Physical Examination

   • Detailed assessment of mass growth, pain, and functional limitations

2. Imaging Studies

   • MRI: Gold standard for local assessment (size, depth, involvement)

   • CT scan: Useful for retroperitoneal tumors and metastasis evaluation

   • Ultrasound: Initial evaluation of superficial lumps

   • PET scan: To detect distant metastases or evaluate therapy response

3. Biopsy

   • Core needle biopsy (preferred for most cases)

   • Incisional biopsy if deeper or inconclusive

   • Histopathological and immunohistochemical evaluation required for subtype diagnosis

4. Staging Workup

   • Based on TNM classification and includes imaging of lungs (common metastasis site), and sometimes bones or abdomen

Best Treatment for Soft Tissue Tumors

Treatment depends on type, location, grade, stage, and resectability of the tumor. It involves a multidisciplinary team including surgical oncologists, radiologists, pathologists, and radiation/medical oncologists.

A. Traditional Treatments

1. Cryo

2. Surgical Resection

   • Wide local excision with negative margins is the mainstay of treatment

   • Limb-sparing surgery is preferred when feasible

   • Amputation only if critical structures are extensively involved

   • May involve reconstructive surgery or skin grafting

3. Radiation Therapy

   • Can be given preoperatively to shrink tumors or postoperatively to prevent recurrence

   • External beam radiation is most commonly used

   • Helps improve local control of high-grade or large tumors

4. Systemic Chemotherapy

   • Used in high-grade sarcomas or metastatic disease

   • Common agents: doxorubicin, ifosfamide, dacarbazine

   • Neoadjuvant (pre-surgery) or adjuvant (post-surgery) use is individualized

B. Advanced Treatments

1. Targeted Therapies

   • Pazopanib: An oral tyrosine kinase inhibitor for non-adipocytic soft tissue sarcomas

   • Trabectedin: Especially effective in liposarcoma and leiomyosarcoma

   • Larotrectinib and Entrectinib: For tumors with NTRK gene fusions (across sarcoma types)

2. Immunotherapy

   • Research is ongoing, but checkpoint inhibitors (e.g., pembrolizumab) are showing promise in certain subtypes like alveolar soft part sarcoma

   • May be combined with other treatments for better efficacy

3. Isolated Limb Perfusion (ILP)

   • A limb-sparing technique where chemotherapy is circulated only through the affected limb using a tourniquet system

   • Often used for large, locally advanced sarcomas

4. Nano-Therapies & Gene Therapies (Experimental)

   • Research is progressing in nanoparticle delivery systems and genetic manipulation to target specific tumor pathways

   • Still mostly in clinical trial phases

Prevention and Lifestyle Management

• Early evaluation of any new or growing soft tissue mass is crucial

• Regular follow-ups for individuals with genetic syndromes linked to sarcoma

• Avoidance of unnecessary radiation exposure

• Prompt treatment of benign tumors that are symptomatic or growing

• Healthy immune system maintenance through diet and fitness

• Participation in clinical trials when appropriate

Prognosis and Survival Rates

Prognosis depends on tumor grade, size, depth, location, and metastatic status:

• Low-grade, superficial, small tumors have >80–90% 5-year survival

• High-grade or deep-seated tumors have lower survival rates (50–70%)

• Metastatic soft tissue sarcomas have poor prognosis; 5-year survival <20%, though novel therapies are improving outcomes in some subtypes

Conclusion

Soft tissue tumors, particularly sarcomas, are rare but complex malignancies requiring individualized and aggressive management. Multimodal treatment combining surgery, radiation, and systemic therapy has become standard. With ongoing advancements in targeted therapy and immunotherapy, outcomes are gradually improving. Early diagnosis, patient education, and personalized care strategies remain crucial for effective disease control and improved quality of life.