What is Trichofolliculoma?
Trichofolliculoma, also known as folliculoma, is a type of skin growth that develops from your hair follicles. It’s one of many types of benign (non-cancerous) hair follicle tumors. These tumors are quite rare and can vary based on the specific type and degree of hair follicle differentiation. Well-known benign hair follicle tumors include trichilemmoma, trichoadenoma, dilated pore of Winer, and trichoblastoma.
Trichofolliculomas are classified as hamartomatous neoplasms, meaning they’re not cancerous but are growths that result from an error in tissue development. They’re typically comprised of well-developed cells with no abnormal features that show an unusual arrangement of tissue. To be more specific, trichofolliculomas typically appear as a cyst-like expansion of one or multiple hair follicle openings, with a central opening to the skin, through which one or more hairs might pass.
What Causes Trichofolliculoma?
Several genetic abnormalities have been found in skin tumors related to hair, sweat and oil glands. However, aside from studies conducted on animals and experimental models, no specific gene mutations or genetic risks have been directly linked to the development of trichofolliculoma, a rare skin condition.
An animal study proposed that a mutation in certain genes responsible for bone growth proteins (BMPs) and pygopus homolog 2 (PYGO2) may be associated with this condition. However, this connection has not yet been confirmed in studies on people, nor has it been repeated in later research. Therefore, the exact cause of trichofolliculoma is still not understood.
Risk Factors and Frequency for Trichofolliculoma
Trichofolliculoma, a condition that usually appears as a single bump on the face or scalp, is most likely to be found in middle-aged adults. However, it can occur at any age, although it’s less common in children and older people.
- In a study of 11 people with trichofolliculoma, the average age at diagnosis was 46, with patients ranging from 20 to 75 years old.
- While evidence hasn’t pinpointed a specific gender that’s more prone to it, some studies suggest that men might be slightly more susceptible.
- No evidence suggests that it affects one racial or ethnic group more than others.
- Even though there have been some cases of trichofolliculoma present at birth, these occurrences are typically spontaneous and aren’t linked to any systemic or skin-related syndromes.
Signs and Symptoms of Trichofolliculoma
Trichofolliculomas are usually pain-free, single, dome-shaped bumps that generally show up on the face, scalp, and neck. These bumps often look like skin-colored pimples with a smooth surface and a noticeable central pore, from which multiple fine, soft hairs (known as vellus hairs) can be seen growing. But it’s important to note that not all trichofolliculomas have these features.
In many cases, the more common sign of trichofolliculomas is a solid bump or lump, typically around 7 mm in size. Studies have shown that only a minority of trichofolliculomas cases have a visible central pore or visible hair tufts. For instance, in a study of 90 cases, researchers found that only 15.5% of cases had a central pore and only 12.2% had visible hair tufts. They also found that most trichofolliculomas were located in the nasal region (40%), followed by the cheek (15%), and the ear (12%). Only a few cases were documented in areas not in the facial region.
- Typically pain-free, dome-shaped bumps
- Commonly found on the face, scalp, and neck
- Most common feature is a solid bump or lump, typically around 7 mm in size
- Minority of cases have a visible central pore (15.5%) or visible hair tufts (12.2%)
- Most common locations: nasal region (40%), cheek (15%), and ear (12%)
Although rare, there have also been reports of trichofolliculomas occurring on the lips, inside the nose, in the external ear canal, and on the upper extremities.
Testing for Trichofolliculoma
If you or your doctor suspect that you might have a condition known as trichofolliculoma, your doctor will start by asking you about your medical history and then do a thorough physical examination. Trichofolliculoma typically shows up as a painless, slowly growing bump on the face. If you have this condition, it’s often noticeable because there’s a group of light-colored hair growing from a single point in the center of the bump.
Diagnosing trichofolliculoma usually doesn’t require any specific lab tests, x-rays, or other exams. It’s important to note that while doctors have found genetic changes in many skin tumors, no specific gene changes have been linked to trichofolliculoma. Also, having trichofolliculoma doesn’t seem to be tied to any particular genetic syndromes or overall body symptoms.
One way doctors might check for trichofolliculoma is by using a kind of examination called dermoscopy. Dermoscopy allows your doctor to examine the skin in more detail. There’s limited information about what trichofolliculoma looks like under dermoscopy because this technique hasn’t been used very widely yet. However, according to the few studies available, dermoscopy may show a “firework pattern” or a “troll doll sign” in trichofolliculoma. The firework pattern refers to a tan-colored center with multiple, radially oriented peripheral projections of dark brown with no pigment networks or prominent vascularization. The troll doll sign refers to a shapeless pink neoplasm (or new growth) with multiple clusters of smooth white vellus hairs that looks like the hair of a troll doll.
However, to confirm the diagnosis, your doctor might need to take a small sample of your skin (a biopsy) for a closer look under the microscope. This is usually necessary because trichofolliculoma can look a lot like other skin tumors such as basal cell carcinoma. Sometimes, the features seen under the microscope may overlap, and additional tests called immunohistochemical staining may be needed to make sure the diagnosis is correct.
Treatment Options for Trichofolliculoma
A biopsy, which is a procedure to remove a small sample of tissue for testing, is often needed to make sure that the growth is indeed a trichofolliculoma, a benign (non-cancerous) skin condition. This test also helps doctors confirm that the growth is not a serious or cancerous tumor. Once a trichofolliculoma is confirmed, there usually isn’t any further treatment necessary.
While typically harmless, you might decide to have the growth removed for aesthetic reasons or if it’s located in a bothersome area. In such cases, possible options could be a simple surgical removal, a procedure known as curettage that scrapes off the growth, or electrodesiccation which uses electrical energy to destroy the abnormal tissue. However, since there isn’t a lot of data on managing trichofolliculoma, there are no standard guidelines doctors follow.
What else can Trichofolliculoma be?
There is often a lot of overlap in how different skin growths look clinically and under the microscope. A diagnosis of trichofolliculoma, a benign hair follicle tumor, can usually be made based on clear, distinctive features seen during a skin examination. However, if there’s no obvious central indentation or hair plug, it can be really difficult to make a diagnosis.
Some benign conditions that might be confused with trichofolliculoma include:
- melanocytic nevus (a type of mole)
- epidermoid cyst
- trichoepithelioma (another benign hair tumor)
- fibrofolliculoma (a benign skin condition featuring hair follicle tumors)
- neurofollicular hamartoma (a type of harmless skin tumor)
Diagnosing trichofolliculoma can become even more challenging if the patient has pulled out the central hair before being examined. Such action can change the skin lesion’s shape and make it harder to distinguish from other conditions like keratoacanthoma, sebaceous hyperplasia, molluscum contagiosum, milium, syringoma, or even a type of skin cancer called basal cell carcinoma.
Since the list of potential diagnoses for a trichofolliculoma can be long and includes conditions that have the possibility of turning into cancer, like squamous or basal cell carcinoma, a definitive diagnosis usually involves taking a skin biopsy and examining it under a microscope.
What to expect with Trichofolliculoma
Trichofolliculomas are non-cancerous growths linked to hair follicles. These growths are known as hamartomas, which are generally viewed as harmless, slow-growing, and self-limiting. This means that they typically stay small, grow very slowly, and tend not to spread or cause other problems.
The outlook for people with trichofolliculomas is excellent, even without treatment, and there’s usually no need for any treatment at all. There has only been one case where a trichofolliculoma was found to spread into the surrounding nerve tissue, but there have been no reported cases of these growths turning into cancer or spreading to other parts of the body.
Possible Complications When Diagnosed with Trichofolliculoma
When a trichofolliculoma (a type of hair follicle tumor) is only biopsied, there’s a high chance of it occurring again. However, these recurrences do not seem to cause any increased health problems or risk of death. When the tumor is completely removed and there’s no sign of any remaining cells, it’s unlikely for the trichofolliculoma to come back. Like any skin procedure for removing tissue (biopsy or excision), potential risks include scarring, bleeding, pain, infection, or nerve damage.
The likely effects include:
- Recurring trichofolliculoma if only a biopsy is done
- Low chance of trichofolliculoma recurrence if completely removed
- Scarring from the skin procedure
- Bleeding from the procedure
- Postoperative pain
- Possible infection from the procedure
- Risk of nerve damage
Preventing Trichofolliculoma
Trichofolliculoma, a harmless skin growth, can appear in people who’ve never had similar skin conditions. As of now, we don’t about any specific risk factors, associated genetic conditions, or other symptoms connected to it. In other words, we don’t fully understand what causes it or how it works.
Because of this, there are no targeted methods to screen for trichofolliculoma or prevent its occurrence. If someone notices a new, unexplained skin growth, it’s essential they consult with a skin doctor, or a dermatologist. Once the doctor confirms the skin growth is indeed trichofolliculoma, patients can be relieved knowing it’s not harmful.
However, if the patient is uncomfortable with the appearance of the trichofolliculoma or if it’s interfering with normal function, there are various ways it can be removed.
