Chapter 44: Lipoma

INTRODUCTION

Lipoma is a benign tumor of mature fat. It presents as a soft subcutaneous flesh-colored tumor that freely moves against overlying skin. Most often, it presents as a solitary lesion on the trunk, neck, and proximal extremities (Fig. 44.1). Infrequently, individuals may present with multiple lipomas, rarely as a part of an inherited syndrome.

EPIDEMIOLOGY

Incidence: very common

Age: can present at any age but most commonly in the fourth decade

Race: none

Sex: equal

Precipitating factors: most frequently, there is no precipitating factor. Multiple lipomas can be associated with syndromes such as Dercum’s disease, familial multiple lipomatosis, Madelung’s disease, Gardner’s syndrome, Bannayan—Zonana and Proteus syndrome

PATHOGENESIS

Unknown.

PATHOLOGY

Well-circumscribed, lobulated tumor of uniform, mature adipocytes in the subcutaneous fat, often with a thin surrounding fibrous capsule and eccentric nuclei.

PHYSICAL LESIONS

A lipoma presents as a soft, freely mobile flesh-colored oval or round subcutaneous nodule with a normal overlying epidermis. Its size can vary greatly from millimeters to many centimeters. It is nontender unless presenting as part of Dercum’s disease, as an angiolipoma or if impinging on a nerve.

DIFFERENTIAL DIAGNOSIS

Epidermal inclusion cyst, pilar cyst, hibernoma, angiolipoma, and other fatty tumors including liposarcoma must be considered. If the lesion is greater than 10 cm or fixed, malignancy should be considered.

LABORATORY EXAMINATION

In normal circumstances, no workup is indicated. In the event of rapid or extensive growth, however, biopsy may be indicated if malignancy is suspected. Caution is indicated in the event of excising a lipoma located in the midline sacrococcygeal region. It may represent spinal dysraphism. In this circumstance, consider radiological and neurosurgical evaluation. Do not perform a biopsy.

COURSE

They tend to grow slowly to a certain size and do not involute without intervention.

KEY CONSULTATIVE QUESTIONS

• Number and location of lipomas

• Family history of similar lesions

• History of keloids/hypertrophic scarring

• Associated pain

• Recent lesional growth

MANAGEMENT

There is no medical indication to treat lipomas unless they produce pain or constriction of movement or demonstrate accelerated growth. Many patients, however, request treatment for cosmesis. Surgical removal, via excision or liposuction, is the mainstay of therapy. If the lesion is located in the midline sacrococcygeal region, consider spinal dysraphism.

TREATMENT

• Surgical excision: best for small lipomas (Figs. 44.2 and ...