Lipoma

Aka: Lipoma, Angiolipoma, Lipomatosis, Infiltrating Lipoma, Pleomorphic lipoma, Spindle cell lipoma, Adenolipoma, Liposarcoma

1. Definition
   1. Subcutaneous tumors of adipose tissue
   2. Usually benign (except in rare cases of Liposarcoma)
2. Associated Syndromes
   1. Hereditary multiple Lipomatosis (Autosomal dominant)
      1. Trunk and extremities most commonly affected
   2. Gardner's Syndrome (Autosomal dominant)
      1. Intestinal polyps
      2. Cyst formation
      3. Osteomas
      4. Parks (2001) J Am Acad Dermatol 45:940-2
   3. Benign symmetric Lipomatosis (Madelung's Disease)
      1. Involves head, neck, Shoulders, proximal arms
      2. Affects men who use Alcohol
      3. Neck may have constricting horse collar appearance
   4. Dercum's Disease (Adiposis dolorosa)
      1. Irregular painful Lipomas on trunk and extremities
      2. Most common in middle aged women
3. Epidemiology
   1. Most common subcutaneous soft-tissue tumor
   2. Age of onset usually 40 to 60 years
   3. Gender prediposition
      1. Single Lipomas more common in women
      2. Multiple Lipomas (Lipomatosis) more common in men
4. Symptoms
   1. Usually asymptomatic
   2. Painful if local compression of nerves
5. Signs
   1. Characteristics
      1. Soft, round, mobile, Rubbery subcutaneous tumor
      2. Most lesions <5 cm (rarely may approach 20 cm)
      3. Overlying skin is normal
   2. Distribution
      1. Lipomas may occur in any subcutaneous location
      2. Common sites
         1. Trunk
         2. Shoulders
         3. Posterior neck
         4. Axilla
6. Differential Diagnosis
   1. Epidermoid Cyst
   2. Liposarcoma (rare, but malignant tumor)
   3. Rheumatic Nodules
   4. Sarcoidosis
7. Histologic Lipoma Types
   1. Infiltrating Lipoma (Lipoma infiltrates muscle)
   2. Angiolipoma (painful Lipomas with numerous vessels)
   3. Pleomorphic lipoma (multinucleated giant cells)
   4. Spindle cell lipoma (intermixed spindle cells)
   5. Adenolipoma (intermixed eccrine Sweat Glands)
   6. Liposarcoma (rare malignant lesion similar to Lipoma)
      1. Located in Retroperitoneum, Shoulders, and legs
8. Indications for excision
   1. Cosmesis
   2. Local nerve compression
   3. Suspect Liposarcoma (malignancy)
      1. Imaging recommended before excision
      2. Red flags for Liposarcoma
         1. Lesion >5 cm
         2. Location in deep thigh
         3. Rapid growth with local nerve or bone invasion
9. Management: Corticosteroid Injection (incomplete removal)
   1. Indicated for Lipomas <1 inch diameter
   2. Protocol
      1. Draw 1:1 mix
         1. Lidocaine 1%
         2. Kenalog 10 mg/ml
      2. Inject 1-3 ml into center of Lipoma
      3. May repeat monthly over several months as needed
10. Management: Liposuction (incomplete removal)
    1. Indicated for Lipomas in areas not amenable to excision
       1. Areas where excision may cause significant scar
       2. Not limited by size of Lipoma
          1. Large Lipomas (>10 cm ideal for this technique)
    2. Protocol
       1. Local anesthetic with Lidocaine
       2. Liposuction via cannula or 16 gauge needle
    3. References
       1. Wilhelmi (1999) Plast Reconstr Surg 103(7):1864-7
11. Management: Standard Lipoma excision
    1. Indicated for large Lipoma
    2. Protocol
       1. Outline entire subcutaneous lesion boundaries
          1. Do not make incision this size
          2. Helps to position excision boundaries
       2. Outline excision boundaries (small central oval)
          1. Much smaller than size of lesion
             1. Length: 50% of Lipoma length
             2. Width: narrow oval, about 20% of Lipoma width
          2. Position centrally over Lipoma
          3. Oval shape should follow Relaxed Skin Tension Lines
       3. Incise oval (inner outlined oval)
       4. Dissect away adjacent tissues
          1. Iris scissors
          2. Small hemostat
          3. Carefully with #15 scalpel (direct visualization)
       5. Remove tumor as a whole
       6. Close dead space with deep 4-0 Vicryl Sutures
       7. Close skin with simple interrupted Nylon Sutures
12. Management: Enucleation Technique (Curette)
    1. Indicated for small Lipoma
    2. Protocol
       1. Incision 3-4 mm in diameter made over Lipoma center
       2. Curette technique
          1. Free attached tissues
          2. Enucleate Lipoma through incision
       3. Cover with pressure bandage to prevent hematoma
13. Management: Narrow Hole Extrusion Technique (Skin Punch)
    1. Indicated for Lipomas on face and extremities
    2. Protocol
       1. Grasp Lipoma tightly
       2. Apply 4 mm skin punch to center of Lipoma
       3. Insert punch to hub into Lipoma
       4. Express Lipoma via incision
          1. Apply firm lateroinferior pressure
          2. Pinch lesion deeply with pressure upward
       5. Explore wound after Lipoma expulsion
       6. Suture as for complete Lipoma excision above
    3. Variation: Pot-Lid Technique
       1. Punched-out piece of skin stored in saline
       2. Lipoma expulsed as above
       3. Two absorbable buried SC Sutures close deep space
       4. Puched-out piece of skin replaced
       5. Bandage in normal fashion
    4. References
       1. Christenson (2000) J Am Acad Dermatol 42(4):675-6
       2. Gupta (2001) Int J Dermatol 40:420-4
14. References
    1. Salam (2002) Am Fam Physician 65:901-5