Skin & Soft Tissue: Soft Tissue Sarcoma

Soft Tissue Sarcoma

Presentation

  • Most Common Presentation: Large, Gradually Enlarging, Painless Mass
  • Can Cause Compression/Pain in Adjacent Nerves
  • Most Common Location: Thigh, Buttock or Groin

Genetic Syndromes

Prognosis/Metastasis

  • Most Tend to Grow Locally & Invade Adjacent Tissues
  • Most Have High Risk of Local Recurrence After Excision
  • Most Important Staging Factors: Histologic Grade, Size & N/M Status
  • Metastases are Most Common in Children
  • Pattern of Spread:
    • Hematogenous – Most Common
    • Lymphatic: Synovial, Clear Cell, Angiosarcoma, Rhabdomyosarcoma & Epithelial Mn
  • Most Common Site of Metastasis: Lung

Diagnosis

  • Initial Diagnostic Step: MRI (Evaluate Etiology, Extent & Invasion)
    • May Consider CT Instead for Abdominal or Retroperitoneal Lesions
    • Consider CT Chest for All Lesions to Evaluate for Pulmonary Metastases
    • Imaging Not Required for Kaposi Sarcoma
    • Imaging Generally Done Prior to Biopsy (Postprocedural Edema May Make MRI Difficult to Interpret)
  • Biopsy (After Imaging):
    • Preferred Method: Core Need Biopsy (CNB)
      • *Incisional Biopsy was the Historic Gold Standard but Now Replaced by CNB
    • May Consider Excisional Biopsy if Small (< 4-5 cm)

Soft Tissue Sarcoma – Staging

TNM

  T N M G (Histology Grade)
1 ≤ 5.0 cm LN+ M+ Score 2-3
2 > 5.0 cm Score 4-5
3 > 10.0 cm Score 6-8
4 > 15.0 cm
    • *Grade Scores from 2-8 Based on Differentiation, Mitotic Count & Extent of Tumor Necrosis
    • *Not Used for GIST, Osteosarcoma or Kaposi Sarcoma

Trunk/Extremity Stage Mn

Stage T N M G
I A T1 N0 M0 Gx-G1
B T2-4 N0 M0 Gx-G1
2   T1 N0 M0 G2-G3
3 A T2 N0 M0 G2-G3
B T3-4 N0 M0 G2-G3
4   Any T N1 Any M Any G
Any T Any N M1 Any G

Retroperitoneum Stage

Stage T N M G
I A T1 N0 M0 Gx-G1
B T2-4 N0 M0 Gx-G1
2   T1 N0 M0 G2-G3
3 A T2 N0 M0 G2-G3
B T3-4 N0 M0 G2-G3
Any T N1 Any M Any G
4   Any T Any N M1 Any G

Soft Tissue Sarcoma – Types

Gastrointestinal Stromal Tumor (GIST)

Liposarcoma

  • Malignant Tumor from Adipocytes
  • Most Common Sites: Extremities & Retroperitoneum
  • Types:
    • Well-Differentiated (De-Differentiated)
    • Myxoid (Round Cell)
    • Pleomorphic
  • Metastatic Potential
    • Low-Risk: Well-Differentiated (De-Differentiated)
    • High-Risk: Myxoid (Round Cell) or Pleomorphic

Retroperitoneal Liposarcoma 1

Leiomyosarcoma

  • Malignant Tumor from Smooth Muscle Cells
  • Most Common Sites: IVC, GI Tract & Uterus
  • Worse Prognosis

Leiomyosarcoma of Small Bowel 2

Rhabdomyosarcoma

  • Malignant Tumor from Cells that were Destined to Become Skeletal Muscle
  • Most Common Soft-Tissue Sarcoma in Peds
    • Less Common in Adults
  • Most Common Locations: Head & Neck, GI Tract & Extremities
  • Classification:
    • Embryonal – Most Common, Intermediate Prognosis
    • Botryoid – “Grape-Like” Polypoid Mas, Favorable Prognosis
    • Alveolar – Poor Prognosis
    • Pleomorphic
  • Sarcoma Botryoides: Generally Describing Rhabdomyosarcoma of the Vagina
    • May Also Be Seen in the Nasopharynx, Bile Ducts or Urinary Bladder
  • Contain Desmin (May Also Be Seen in Leiomyosarcoma)

Rhabdomyosarcoma of Thigh 3

Dermatofibrosarcoma Protuberans (DFSP)

  • Locally Aggressive Cutaneous Sarcoma with High Risk of Local Recurrence
  • Infiltrating Growth Pattern, Commonly Extends Beyond Margins
  • Majority (85-90%) are Low-Grade with Low Metastatic Potential
    • Exception: Fibrosarcomatous Variant (DFSP-FS) is High-Grade with Increased Risk of Metastasis
  • Associated with a t(17;22) Mutation
  • Presentation:
    • Mostly Asymptomatic
    • Early:
      • Indurated Plaque
      • Overlying Skin Can Be Normal, Brown-Yellow, Red or Atrophic
      • Margins Violet-Red or Blue
    • Later:
      • Raised, Firm Nodule
      • Surrounding Skin Telangiectatic
      • Can Ulcerate & Bleed
  • Most Common Sites:
    • Trunk (42%)
    • Lower Extremities (21%)
    • Upper Extremities (21%)
    • Head & Neck (13%)
    • Genitals (1%)
  • Histology: Finger-Like Projections of Spindle Cells in an Irregularly Whorled/“Storiform” Pattern

Dermatofibrosarcoma Protuberans 4

Osteosarcoma

  • Malignant Tumor of Bone
  • Bimodal Age Distribution – Peds (13-16 Years) & Elderly (>65)
  • Most Common in the Metaphysis of Long Bones
    • Most Common Sites: Distal Femur (75%), Proximal Tibia & Proximal Humerus
  • May Be Associated with Pathologic Fractures
  • Imaging May Demonstrate:
    • “Codman Triangle” – Single or Multilayered Periosteal Reaction with Shells of New Ossified Bone Due to Speed of Growth
    • “Sunburst” – Sharpey’s Fibers Extend Perpendicularly to Bone When Lesions Grow Too Fast to Ossify a New Layer

Osteosarcoma with Codman Triangles & Sunburst Appearance 5

Synovial Sarcoma

  • Histologically Similar to Synovial Cells Although Origin is Unknown
  • Most Common in Extremities of Young Adults
  • Many are Associated with the Chromosomal Translocation t(X;18)(p11;q11)

Angiosarcoma

  • Highly Malignant Tumor of Blood Vessels or Lymphatics
  • Types:
    • Hemangiosarcoma – From Blood Vessels
    • Lymphangiosarcoma – From Lymphatics
  • Most Common in Breast, Head or Neck
  • Risk Factors:
    • Radiation Exposure – May Be Seen After Treatment for Breast Cancer or Lymphoma
    • PVC
    • Arsenic
    • Lymphangiosarcoma is Often Associated with Chronic Lymphedema
  • Highly Sensitive to Chemotherapy

Radiation-Induced Angiosarcoma 6

Kaposi Sarcoma

  • Angioproliferative Tumor of Blood Vessels or Lymphatics Caused by Human Herpes Virus 8 (HHV-8)
  • Most Common AIDS-Associated Malignancy
  • Types:
    • Classic – Seen in Elderly Men, Most Common in Legs/Feet
    • Endemic – Seen in Sub-Saharan Indigenous Africans
    • Iatrogenic – Associated with Immunosuppression, Often After Transplants
    • Epidemic – AIDS-Associated
  • Presentation:
    • Purple or Reddish-Blue Macules or Skin Nodules
    • May Ulcerate or Bleed
    • Very Slow Growing
  • Low Mortality Risk

Kaposi Sarcoma 7

Malignant Peripheral Nerve Sheath Tumor (MPNST)

  • Malignant Tumor of Peripheral Nerves
  • Half are Associated with Neurofibromatosis Type 1
  • May Express S100 Protein – Not Seen in All

Undifferentiated/Unclassified (Sarcoma, Not Otherwise Specified)

  • Previously Called “Malignant Fibrous Histiosarcoma (MFH)”
  • Previously was Considered the Most Common Type of Sarcoma – No Longer True as Many Previously Unidentified Sarcomas Have Been Reclassified

Soft Tissue Sarcoma – Treatment

General Treatment

  • Primary Treatment: Wide Local Excision (WLE)
    • Margins: 1-2 cm
      • Failure to Obtain Oncologically Appropriate Margins: Re-Resection vs Radiation Therapy
        • May Consider Observation for Stage IA
    • Consider Amputation If Unresectable
  • Neoadjuvant/Adjuvant Therapy:
    • XRT: Consider for ≥ Stage II or Close Margins
    • Chemotherapy: Consider for ≥ Stage III
  • Metastases:
    • Isolated: Resect
    • Systemic Disease: Palliative Chemo-XRT

Dermatofibrosarcoma Protuberans (DFSP)

  • Primary Treatment: WLE (2-4 cm Margins)
    • May Consider Mohs Micrographic Surgery if Large, Recurrent or Cosmetically Sensitive Area
    • May Consider Adjuvant Radiation Therapy
  • Metastases:
    • Resectable: Surgical Resection
    • Unresectable: Imatinib (Tyrosine Kinase Inhibitor)

Kaposi Sarcoma

  • Classic Kaposi Sarcoma:
    • Asymptomatic: Can Observe
    • Symptomatic or Cosmetically Unacceptable: Local Treatment
      • Surgical Excision
      • Radiation Therapy
      • Liquid Nitrogen Cryotherapy
      • Intralesional Injections
  • AIDS-Associated: Highly Active Antiretroviral Therapy (HAART) & Palliation
    • May Consider Local Treatment of a Specific Symptomatic Lesion

Follow Up

  • Physical Exam:
    • Every 3-6 Months for 2-3 Years
    • Then:
      • Stage I: Annually
      • Stage II-III: Every 6 Months for 2 Years, Then Annually
  • Imaging:
    • Periodic Imaging (CXR & CT/MRI)

Mnemonics

Soft Tissue Sarcomas That Spread by Lymphatics

  • “SCARE”
    • Synovial
    • Clear Cell
    • Angiosarcoma
    • Rhabdomyosarcoma
    • Epithelial

Soft Tissue Sarcoma TNM Staging

  • Grade 1 – Stage 1
  • Grade 2-3 – Stage 2-3
  • N – Stage 4 (Trunk/Extremity) or Stage 3B (Retroperitoneum)

References

  1. Francis IR, Cohan RH, Varma DG, Sondak VK. Retroperitoneal sarcomas. Cancer Imaging. 2005 Aug 23;5(1):89-94. (License: CC BY-4.0)
  2. Sailer J, Zacherl J, Schima W. MDCT of small bowel tumours. Cancer Imaging. 2007 Dec 17;7(1):224-33. (License: CC BY-4.0)
  3. Van Rijn RR, Wilde JC, Bras J, Oldenburger F, McHugh KM, Merks JH. Imaging findings in noncraniofacial childhood rhabdomyosarcoma. Pediatr Radiol. 2008 Jun;38(6):617-34. (License: CC BY-NC-2.0)
  4. Hamid R, Hafeez A, Darzi MA, Zaroo I, Rasool A, Rashid H. Outcome of wide local excision in dermatofibrosarcoma protuberans and use of radiotherapy for margin-positive disease. Indian Dermatol Online J. 2013 Apr;4(2):93-6. (License: CC BY-NC-SA-3.0)
  5. Plant J, Cannon S. Diagnostic work up and recognition of primary bone tumours: a review. EFORT Open Rev. 2017 Mar 13;1(6):247-253.(License: CC BY-NC-4.0)
  6. Aljarrah A, Nos C, Clough KB, Lefrere-Belda MA, Lecuru F. A case report on radiation-induced angiosarcoma of breast post skin-sparing mastectomy and reconstruction with transverse rectus abdominal muscle. Ecancermedicalscience. 2014 Feb 17;8:402.(License: CC BY-3.0)
  7. OpenStax College. Wikimedia Commons. (License: CC BY-3.0)