Nevus Lipomatosus
Superficialis
Nevus lipomatosus superficialis is a not-uncommon benign skin growth that
is considered to be a hamartomatous proliferation of adipose tissue located in
the dermis. It was originally named nevus lipomatosus cutaneous superficialis
of Hoffman-Zurhelle. There are no known systemic associations with this benign
skin growth, and no inheritance pattern has been described.
Clinical Findings: These nevi are most commonly found along the
pelvic girdle. They have no sex or race predilection. They may occur at any age
but are most common before the third decade of life. The lesions usually have a
soft, bag-like appearance, often mimicking a large skin tag, and are flesh
colored to yellow-tan. They are soft, nontender, easily moveable papules with a
sessile base or pedunculated plaques with a thick stalk-like projection. The
main differential diagnosis includes a skin tag, a compound nevus, and a
connective tissue nevus. However, these lesions are much larger on average than
the common skin tag.
Although the diagnosis can be
considered clinically, the definitive diagnosis can be ascertained only after
pathological evaluation. These lesions are often solitary, but reports of
multiple lesions have been described in the literature. In the case of multiple
tumors, the lesions are typically described as flesh-colored to slightly red
dermal nodules that tend to coalesce into larger plaques. Some of the tumors
have a cerebriform appearance to their surface. They can become very large (>10
cm in diameter) if left untreated. However, most never grow larger than 1 to 2
cm in diameter. A generalized variety of this condition has been described, but
it is exceedingly uncharacteristic.
Children present after their parents
notice the growth or growths, and a skin biopsy is often used to determine the
diagnosis. Adults often present because of a slowly enlarging plaque that has
an unsightly appearance or has become eroded or ulcerated due to trauma from
the size of the lesion.
Pathogenesis: This condition is believed to be a hamartomatous
process of adipose tissue located in the dermis. For some unknown reason, this
normal-appearing adipose tissue proliferates within the dermis, often causing
an outward herniation of the overlying epidermis, which ultimately leads to the
distinctive clinical findings. The exact mechanism has not been elucidated. No
genetic abnormalities of the adipose tissue have been established, and there is
no known malignant potential.
Histology: Nevus lipomatosus superficialis has a
characteristic pathology. It shows mature normal adipose tissue within the
dermis. The one key finding is lack of connection of the abnormally located
dermal adipose tissue with the normally located subcutaneous adipose tissue.
Variable amounts of fat tissue make up the individual lesions. No definitive
percentage has been established to make the diagnosis, but as little as 10% to
more than 50% of each lesion is made up of adipose tissue. The overlying
epidermis can be normal or can exhibit acanthosis and papillomatosis. The more
cerebriform appearing the lesion is clinically, the more likely it is that
epidermal changes will be seen on pathological examination. Skin tags do not have
adipose tissue present, and this is a key discrimi- nating factor.
Treatment: These solitary lesions are best excised
surgically; this gives the best cosmetic result and the best cure rate.
Multiple lesions can be left alone after a diag- nosis is made. If the group of
lesions is amenable to surgical excision without the potential for disfiguring
scarring, or if the scarring would result in a better cosmetic outcome,
surgical excision can be undertaken.
