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LIPOMA

Introduction

Lipomas are common, benign soft tissue tumors comprised of fat cells. Depending on their location, lipomas may be asymptomatic or cause significant pain and/or functional impairment. Because they are usually well encapsulated, lipomas can be removed by careful marginal excision.

Related Anatomy

  • Commonly occur subcutaneously or adjacent to nerves or muscles in the hand or forearm

Relevant Basic Science

  • Composed of mature adipocytes arranged in lobules, surrounded by a fibrous capsule

Incidence and Related Conditions

  • Hereditary multiple lipomatosis, adiposis dolorosa, Gardner's syndrome, and Madelung's disease

Differential Diagnosis

  • Ganglion cyst
  • Epidermoid cyst
  • Liposarcoma
  • Metastatic disease
  • Erythema nodosum
  • Weber-Christian panniculitis
  • Sarcoidosis
  • Nodular fasciitis
  • Nodular subcutaneous fat necrosis
  • Vasculitic nodules
  • Rheumatic nodules
  • Infection (eg, onchocerciasis, loiasis)
  • Hematoma
Clinical Presentation Photos and Related Diagrams
  • Lipoma Proximal Dorsal Forearm with PIN Palsy (Hover over right edge to see more images)
    Lipoma Proximal Dorsal Forearm with PIN Palsy (Hover over right edge to see more images)
  • Lipoma Proximal Dorsal Forearm with PIN Palsy
    Lipoma Proximal Dorsal Forearm with PIN Palsy
  • Lipoma Proximal Dorsal Forearm with PIN Palsy
    Lipoma Proximal Dorsal Forearm with PIN Palsy
  • Partial PIN Palsy secondary to Lipoma Proximal Dorsal Forearm
    Partial PIN Palsy secondary to Lipoma Proximal Dorsal Forearm
  • Lateral view of lipoma in finger tip
    Lateral view of lipoma in finger tip
  • Palmar view of lipoma in finger tip
    Palmar view of lipoma in finger tip
  • Excised lipoma of finger tip
    Excised lipoma of finger tip
  • Palpating lipoma in carpal tunnel
    Palpating lipoma in carpal tunnel
  • Excision of lipoma from the carpal tunnel
    Excision of lipoma from the carpal tunnel
Symptoms
Complaining of rubbery, soft, moveable mass
Mass is not painful
Mass size may change with changes in weight
Typical History

A patients with a lipoma ususally is a middle aged individual who presents with a mass. Frequently the mass has been present for several months. The mass generally is either painless or has some associated soreness but no night pain. The patient may note that the mass size varies in size with the patient's weight gain or loss.

Positive Tests, Exams or Signs
Mass: Mobility, Size, Tenderness, Texture
Work-up Options
Sonographic studies - Ultrasound
Radiology studies - X-ray
Magnetic resonance imaging - MRI without contrast
Images (X-Ray, MRI, etc.)
  • Note the radiolucent mass in the proximal radial forearm. Lipomas frequently appear darker on plain X-ray than the surrounding muscle. This radiographic finding is called a Bufalini Sign.
    Note the radiolucent mass in the proximal radial forearm. Lipomas frequently appear darker on plain X-ray than the surrounding muscle. This radiographic finding is called a Bufalini Sign.
Treatment Options
Conservative: 
  • Watchful waiting if no pain, not enlarging and not interfering with other structures like nerves
  • Steroid injection
  • Liposuction
Operative: 
  • Marginal excision including the capsule of the lipoma
Complications

Operative:

  • Infection, ecchymosis, hematoma, and/or seroma
  • Nerve injury, artery injury, and/or muscle injury
  • Excessive scarring
  • Recurrence
Outcomes
  • Operative treatments generally provide a cure.
Key Educational Points
  • Benign soft-ttisue masses are approximately 200 times more common than malignant ones, lipomas being the most common.
  • Lipomas are usually non-tender, soft, subcutaneous masses.
  • Lipomas should be considered for surgical excision if they enlarge, cause symptoms (pain or numbness from pressue on a nerve) or cause significant cosmetic conderns.
Practice and CME
References

New Articles

  1. Nakamura S, Okazaki M, Tazaki K. A case report of a giant forearm lipoma causing anterior interosseous nerve palsy after fracture of the distal radius. Hand Surg 2014;19(1):109-11.
  2. Elbardouni A, Kharmaz M, Salah Berrada M, et al. Well-circumscribed deep-seated lipomas of the upper extremity. A report of 13 cases. Orthop Traumatol Surg Res 2011;97(2):152-8.
  3. Doyle JR. Tumors. In Tornetta P and Einhorn TA,eds. Orthopaedic Surgery Essentials Hand and Wrist. Philadelphia: Lippincott Wiiliams & Wilkins. 2006:44.

Reviews

  1. Tahiri Y, Xu L, Kanevsky J, Luc M. Lipofibromatous hamartoma of the median nerve: a comprehensive review and systematic approach to evaluation, diagnosis, and treatment. J Hand Surg Am 2013;38(10):2055-67.
  2. Gupta A, Singal R, Mittal A, Goyal M. Report of two cases of subcutaneous lipoma over the finger and review of literature: case series: benign tumour. Musculoskelet Surg 2011;95(3):247-9.

Classics

  1. White WL and Hanna DC. Troublesome lipomata of the upper extremity. J Bone Joint Surg Am 1962;44-A:1353-9.
  2. Pozner JN, Canick ML, Ramirez OM. Endoscopically assisted lipoma removal. Plast Reconstr Surg 1996;98(2):376-7.