Also known as nevus sebaceus of Jadassohn or organoid nevus, Nevus sebaceus (sebaceous nevus) is a common type of congenital epidermal naevi (epidermal birthmark) that forms on the scalp, forehead, face, front of the ears, and/or neck.
Call us today at (65) 6532 2400 to book an appointment on any of our cosmetic services and treatments.
Cancerous tumour formation in sebaceous nevus
More than just a cosmetic deformity, sebaceous nevi (singular: sebaceous nevus) are hair follicle tumours that are usually benign in nature but can develop into malignant lesions (cancerous tumours). Medical studies indicate that around 24% of patients suffering from nevus sebaceus develop secondary tumours, with 80% of secondary tumours being benign (non-cancerous) while up to 20% of secondary tumours are malignant.
Types of secondary tumours that can develop in sebaceous nevi include small benign tumours like trichoblastomas, trichilemmomas, infundibular cysts, sebaceomas, and sweat gland tumours, as well as malignant tumours such as basal cell carcinomas, squamous cell carcinomas, sebaceous carcinoma, and apocrine/eccrine carcinomas.
Please note that if you suffer from any of the symptoms of skin cancer mentioned below, we strongly recommend immediately consulting a medical professional:
Basal cell carcinoma – locally invasive (able to spread) nonmelanoma skin cancer/keratinocyte cancer that presents as skin coloured or pigmented plaques/nodules on the skin that vary from a few millimetres to several centimetres in diameter. Basal cell carcinoma can also take the form of open sores that do not heal, or waxy and flat scar-like patches on the skin.
Squamous cell carcinoma – skin cancer of the keratin producing cells in the epidermis that can be cutaneous (isolated to the top layer of the skin) or metastatic (has spread to other parts of the body). Large red flat patches of skin (around 2.5 centimetres in diameter), presence of enlarging lump/bump like growths on the skin that may be scaly/crusted/scabbed over, growths with depressed centres, or open wounds/sores that do not heal are signs of squamous cell carcinoma.
Sebaceous carcinoma – aggressive skin cancer that develops in the sebaceous glands (oil glands). This type of cancer appears as a pimple-like growth/bump on the skin and most commonly affects the eyelids.
Apocrine/eccrine carcinoma – locally aggressive tumours arising from the apocrine eccrine sweat glands respectively. This type of carcinoma has a high rate of recurrence and typically present as a single or multinodular brown/bluish/reddish-purple firm lump (less than 0.5 centimetres in diameter) that may show signs of inflammation or ulceration.
Symptoms of nevus sebaceus
Nevus sebaceus typically presents as a solitary hair-less pale to yellow coloured plaque on the skin, that can be smooth or wart-like (verruciform) in texture. Nevus sebaceus affects all races and genders equally and presents at birth or early childhood, usually occurring on the scalp, forehead, face, front of the ears, and/or neck.
Characteristics in children vs adults
Hormonal changes during puberty trigger cell proliferation and increased cell production (hyperplasia) of the sebaceous nevus which result in it undergoing a growth phase that alters its appearance to become larger and more wart-like (verrucous), worsening any cosmetic disfigurement perceive by the patient. The development of secondary tumours (benign or malignant) can also occur during this phase or later on in life after puberty.
Nevus sebaceus in children and infants:
- Slightly raised or flat plaque that can be smooth or velvety in texture.
- Hairless area that is typically present at birth; presents as alopecia if found on the scalp.
- Pale to yellow discolouration, yellow-orange, or tan in appearance.
- Typically presents as a solitary plaque.
- Round, oval, or linear shaped, ranging from a few millimetres to several centimetres in diameter.
Nevus sebaceus in adults:
- More pronounced; larger in diameter with a thicker epidermis compared to what the nevus looked like pre-puberty.
- Verrucoid/verrucous (wart-like), bumpy, or scaly in appearance.
- Pale to yellow discolouration, yellow-orange, or tan in appearance.
- Hairless, well-demarcated (well defined boarder between the nevus and surrounding tissue), and usually solitary.
- May develop secondary/appendageal tumours.
Causes of nevus sebaceus
Nevus sebaceus of Jadassohn is a congenital (present from birth) malformation that originates in the epithelial and adnexal structures of the skin; it is a congenital (present from birth) skin hamartoma caused by an abnormal overgrowth of sebaceous (oil) glands.
Hamartoma – malformation that presents as a usually benign mass of tissue (tumour) formed due to aberrant and disorganized growth of mature cells.
Surgical excision of nevus sebaceus
Surgical removal is fully claimable under medical insurance and is usually recommended for larger nevi that cause greater cosmetic deformity due to their size or location, for nevi that are suspected to be developing/have developed malignant secondary tumours, and for nevi that tested positive for the presence of malignant secondary tumours.
Development of a new nodule/bump on a formerly stable sebaceous nevus may indicate secondary tumour formation. In such cases, it is advisable to conduct a biopsy to determine if the secondary tumour is benign or malignant.
What to expect before and during the procedure
Prior to the procedure, a consultation session will be arranged with one of our doctors to determine the severity of the sebaceous nevus/nevi and if the patient is a suitable candidate for surgical excision of nevus sebaceus.
Before the excision is performed, pre-surgical markings are done, and the patient is injected with a local anaesthetic to eliminate sensation at the excision site.
The nevus is surgically removed, and the excision site/wound is closured by sutures (primary closure). The excised tissue can be sent for a biopsy at the patient’s request.
When should I seek surgical intervention?
Surgical excision can be performed pre- or post-puberty; as surgical excision is an elective procedure, some patients may opt to have the procedure done post-adolescence as secondary tumour formation typically occurs only after puberty, while some patients may choose to do the excision pre-puberty before the nevus undergoes its growth phase.
Benefits of performing surgical excision pre-puberty:
- Excision can be performed as pre-emptive measure to remove the sebaceous nevus/nevi before it has a chance to develop a potentially malignant secondary tumour.
- It is easier to excise the sebaceous nevus/nevi pre-puberty as it is has not undergone pubertal enlargement and thickening, and children/infants have greater skin laxity.
- Prevents unnecessary injury as while nevus sebaceus generally do not cause pain or discomfort, some children may pick at or scratch the sebaceous nevus/nevi, leading to bleeding or ulcer formation.
Ultimately, when surgical excision is performed (pre- or post-puberty) is left to the discretion of the patient. However, if a formerly stable sebaceous nevus/nevi is exhibiting abnormal changes in its appearance or structure, it is advisable to immediately perform a biopsy/seek surgical intervention. Additionally, for younger patients, the age of the patient determines their suitability for surgical excision as it determines their ability to safely tolerate the use of general anaesthetic and, should local anaesthesia be used, if they are able to keep still during the procedure.
Is the procedure painful?
Surgical excision will be performed under local anaesthesia to minimise any pain or discomfort felt during the procedure. Our doctors will prescribe pain relief medication post-procedure as necessary.
Where will the excision be performed?
The Clifford Clinic/Surgery is a licensed ambulatory surgical centre. The excision will be performed in our clinic by our doctors, and you may leave the clinic immediately after the procedure.
Is there any down time after the excision?
Recovery typically takes between 2 to 3 weeks for most patients. While you are free to carry on with your usual daily activities during the recovery period, do note that physical activity should be avoided to prevent irritating or infecting the wound.
Are there any potential risks or complications?
All surgical procedures involve risk, but surgical excision of nevus sebaceus is generally considered to be safe and low risk. The most common complication post-surgery is an infection if the wound is not properly cared for. Depending on the thickness and size of the sebaceus nevus removed, post-surgery scarring is another potential risk of surgical excision.