Are you worried about the warty patches of hair loss on the scalp of your infant son or cousin? Is it circumscribed by a tan? The problem may be a condition known as Nevus Sebaceous. Read on to know more about the disease, including its incidence, main causes, diagnosis and treatment options.
Nevus Sebaceous Definition
Nevus Sebaceous (NV) refers to the congenital hairless plaque of the skin that is outlined by premature hair follicles, hyperplasia of the epidermis, and apocrine and sebaceous glands. This disorder of the skin falls in the category of epidermal nevus and typically occurs on the scalp and face. Ears, face, trunk, neck and the oral mucosa are, the less frequently affected areas. By the time a patient hits puberty, this benign skin disorder starts to thicken and covers the affected area with warts.
Nevus Sebaceous Synonyms Other Names (Synonyms)
NV, also called as Sebaceous Nevus and Nevus Sebaceus of Jadassohn is named due to overgrowth of sebaceous glands in the nevus. Since it may consist of elements of the entire skin, this disorder is also termed as Organoid Naevus.
Nevus Sebaceous Incidence
The incidence of the disease peaks in newborns and is estimated at 1 in 1000. NV is the association of large sebaceous naevus and are present at birth, affecting both males and females of all races. The lesion develops in three phases corresponding to the growth of the sebaceous glands from childhood, puberty to adulthood.
Nevus Sebaceous Appearance
How does Nevus Sebaceous look like?
NV is a solitary-yellow colored plaque found mainly on the scalp and forehead. This patch is typically oval or linear shaped and measures roughly 1 to 3 cm in diameter. It becomes more noticeable around adolescence and often appears bumpy or scaly.
Nevus Sebaceous Causes
This skin abnormality arises from a deformity in the ectoderm. Postzygotic mosaic mutations in the KRAS or HRAS genes have also been reported to give rise to sebaceous naevi. NV also reacts to hormonal influences, since the lesion can arise at birth, become leveled in childhood and rise again in puberty.
Nevus Sebaceous Diagnosis
Due to its characteristic clinical appearance, this benign skin ailment is often diagnosed during adolscence. In rare cases, the diagnosis is conducted by a pathologist after the lesion is removed by a surgery. A visit to the dermatologist or tissue biospy is recommended in case of uncertain diagnosis. For enlarged and exophytic lesions, prenatal diagnosis by x ultrasonography is a viable option.
The differential diagnosis of this condition involves telling other lesions which may impact similar areas of the body. Such lesions include:
- Aplasia cutis congenita
- Solitary mastocytoma
- Naevus syringocystadenomatosus papilliferous
- Juvenile xanthogranulomata
- Other causes of alopecia
Nevus Sebaceous Associated Tumors
Nearly all sebaceous naevi remain consistent throughout life without causing any problem. However, within the lesion another tumor may grow, which is benign in 0-50% of the cases. It is called as trichoblastoma.
Other such benign tumors may include:
- sebaceous adenoma
- nodular hidradenoma
- trichilemmoma trichoepithelioma
- follicular poroma
- sebaceous epithelioma
- apocrine cystadenoma
- seborrheic keratosis
- apocrine hidrocystoma.
Carcinoma is one of the most common malignant tumors in basal cell. Apocrine carcinoma, ductal adenocarcinoma, squamous cell carcinoma, porocarcinoma, trichilemmal carcinoma, syringomatous carcinoma, sebaceous carcinoma and anaplastic adnexal carcinoma are other such malignant tumors that require constant observation under medical supervison.
Nevus Sebaceous Treatment and Removal
As aforesaid, this hair follicle tumor needs constant monitoring. In the event of a sore or lump within a sebaceous naevus, a dermatologist should be consulted immediately. Depending on the medical condition of the patient, a biopsy or excision of the overall sebaceous naevus may be required.
Few doctors advocate the effective use of phototherapy with topical aminolaevulinic acid to enable surgical removal of the lesion in particular areas. As per medical survey reports, this treatment has received good response in limited cases.
Nevus Sebaceous Prognosis
The prognosis of this disorder is good, however, approxiamtely 1% of the patients experience malignant transformation, generally in adulthood or adolescence. In few instances, malignant transformation in children have also been reported.
Nevus Sebaceous Complications
Bad cosmetic appearance and rapid enlargement or growth of an exophytic nodule may inject the suspicion of malignant transformation.
Any lesion which has changed its appearance, bleeds or has become painful must be referred to a dermatologist or a skin specialist immediately. Such patients should also be examined for associated findings. To be on the safer side, get medical assistance the moment you witness any new bump within a nevus sebaceous for thorough examination.
Nevus Sebaceous Pictures
Check out some of the pictures of Nevus Sebaceous.
Nevus Sebaceous ICD9 code
The ICD9 Code for this disorder is 702.8