Hyperplasia

Dermatofibroma

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Dermatofibroma, Solitary histiocytoma, Sclerosing Hemangioma, Nodulus Cutaneous, Fitzpatrick's Sign

  • Epidemiology
  1. Males predominate (3:1 ratio)
  2. Age of onset 20-50 years old
  • Pathophysiology
  1. Idiopathic, benign, fibroblast proliferation
  • Causes
  1. Idiopathic benign skin tumor
  2. Fibrous reaction to local irritation
    1. Local Trauma
    2. Insect Bite
    3. Viral infection
    4. Folliculitis
  3. Underlying condition (>15 Dermatofibromas)
    1. Immunocompromised patient
    2. Autoimmune Condition
  • Symptoms
  1. Asymptomatic in most cases
  2. Lesions may be pruritic or tender
  • Signs
  1. Characteristics
    1. Small firm, raised Papule, Plaque or Nodule (3-10 mm)
    2. Lesions develop over months and persist for years
    3. Completely symmetric and regular
    4. Tan or light brown surface (may be red or yellow)
      1. Color is darker at center and gradually fades into normal Skin Color
    5. Fitzpatrick's Sign
      1. Skin dimples downward with lateral compression
  2. Distribution
    1. Most common: Anterior thighs and Legs
    2. Moderately common: Arms and Trunk
    3. Uncommon: Head, Palms, and Soles
  3. Variants
    1. Multiple eruptive lesions
      1. Seen in 0.3% of cases (typically immunocompromised: HIV, SLE)
      2. More than 15 Dermatofibromas are otherwise rare aside from this condition
    2. Dermatofibrosarcoma protuberans
      1. Deep invasion with metastases
  • Differential Diagnosis
  1. Primary Malignant Melanoma
  2. Scar
  3. Blue Nevus
  4. Pilar Cyst
  5. Metastatic Carcinoma
  6. Kaposi's Sarcoma
  • Management
  1. Excision Indications
    1. Repeated Trauma with bleeding, irritation
    2. Unacceptable cosmetic appearance
    3. Uncertain diagnosis (changes in size, color)
  2. Techniques
    1. Eliptical excision or Punch Biopsy
      1. Risk of scarring
    2. Other methods (incomplete removal)
      1. Laser ablation (may be preferred)
      2. Shave Biopsy
      3. Cryotherapy
  • References
  1. Fitzpatrick (1999) Color Atlas Dermatology
  2. Higgins (2015) Am Fam Physician 92(7): 601-7 [PubMed]