Skin & Soft Tissue: Squamous Cell Carcinoma (SCC)

Basics

• Tumor from Epidermal Keratinocytes
• Appearance: Papulonodular with Ulceration & Crusting
• Second Most Common Skin Cancer
• Histology: Hyperkeratosis
  • Actinic Keratosis: Partial Thickness Nuclear Pleomorphism
  • SCC In Situ: Full Thickness Nuclear Pleomorphism
  • SCC: Invasion Through Basement Membrane into Dermis

Risk Factors

• Actinic Keratosis
• Cumulative Sun Exposure
• Fair Skinned
• Elderly
• Norther European Ancestry

Special Types

• Marjolin’s Ulcer
  • From Chronic Healing Wounds/Burns
• Bowen’s Disease
  • Cutaneous SCC In Situ
  • More Common on Trunk, Lower Extremities or Genitalia
  • Perianal Lesions are Associated with HPV
  • Tx Options: Excision, Cryotherapy or Topical Imiquimod

High-Risk Factors for Local Recurrence

• ≥ 2 cm on Trunk or Extremities
• ≥ 1 cm on Cheeks, Forehead, Scalp, Neck or Pretibial
• Any Size on Face, Genitalia, Hands or Feet
• Poorly Defined Borders
• Recurrence
• Immunosuppressed
• Site of Prior XRT
• Rapid Growth
• Neurologic Symptoms
• Pathology:
  • Poorly Differentiated
  • Subtypes Acantholytic, Adenosquamous, Desmoplastic or Metaplastic
  • Depth > 6 mm or Invasion Beyond Subcutaneous Tissue
  • Perineural, Lymphatic or Vascular Invasion

Treatment

• Tx: Excision
  • Low-Risk: 0.4-0.6 cm Margins
  • High-Risk: 1.0 cm Margins or Consider Mohs Micrographic Surgery if High-Risk
  • Positive Margins: Repeat Excision (With Wider Margins – Exact Length Uncertain) or Mohs Micrographic Surgery
• Nodal or Distant Mets:
  • Resection if Able
  • Consider Chemo/XRT