Hyperplasia

Seborrheic Keratosis

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Seborrheic Keratosis, Seborrheic Keratoses, Stucco keratoses, Dermatosis papulosa, Leser-Trelat Sign

  • Epidemiology
  1. Most common benign epithelial tumor
  2. Occurs in patients over age 30 years old
  3. Number of lesions increase with age
  4. Men and women affected equally
  5. Autosomal Dominant inheritance
  • Pathophysiology
  1. Common benign, hereditary tumor
  2. Hyperkeratotic epidermal lesion
  • Signs
  1. Characteristics
    1. Early (Flat lesions)
      1. Small (<3mm)
      2. Slightly elevated
      3. Variable hyperpigmented coloration
    2. Late (Raised pigmented lesions)
      1. Large Plaque (1 to 6 cm)
      2. May feel greasy, velvety or warty
      3. Keratotic (warty) appearance
        1. Appears "stuck-on" like clay
        2. Rough surface
      4. Yellow, tan, brown or black pigmentation
      5. Sharp well-circumscribed border
  2. Distribution (typically multiple are present)
    1. Trunk (most common location)
    2. Face
    3. Scalp
    4. Upper extremities
  3. Associated lesions
    1. Horn cysts
    2. Milia-like cysts
  • Variants
  1. Stucco keratoses
    1. Numerous small white, dry scaly lesions on extremity
  2. Dermatosis papulosa
    1. Small, dark Papules on face seen in darker skin
  3. Leser-Trelat Sign (paraneoplastic sign)
    1. Sudden onset and increase in number of keratoses
    2. Requires thorough evaluation for malignancy
    3. Seborrheic Keratoses often resolve with malignancy treatment and reappear with cancer recurrence
    4. Associated with underlying adenocarcinoma
      1. Stomach Cancer
      2. Colon Cancer
      3. Breast Cancer
  • Differential Diagnosis
  1. Early Seborrheic Keratosis (Flat)
    1. Solar Lentigo
    2. Spreading pigmented Actinic Keratosis
    3. Malignant Melanoma
  2. Late Seborrheic Keratosis (Raised pigmented)
    1. Pigmented Basal Cell Carcinoma
    2. Malignant Melanoma
  • Management
  1. Indications for excision
    1. Cosmesis
    2. Local irritation due to recurrent Trauma
    3. Malignancy suspected (Excisional Biopsy needed)
  2. Techniques
    1. Curettage with light Electrocautery
      1. Inject Local Anesthesia first
      2. Lesion easily rubs off
      3. Lightly cauterize base to prevent recurrence
    2. Cryotherapy with Liquid Nitrogen
      1. May not be effective in very thick lesions
    3. Excision
      1. Shave Excision
      2. Excisional Biopsy (if possible Melanoma)
    4. Topical Corticosteroids
      1. Indicated for irritated Seborrheic Keratoses
  • References
  1. Fitzpatrick (1999) Color Atlas Dermatology
  2. Higgins (2015) Am Fam Physician 92(7): 601-7 [PubMed]