What is Calcifying Epithelioma of Malherbe?
Pilomatrixoma, also known as calcifying epithelioma of Malherbe, is a harmless growth that comes from the root of a hair follicle. Back in 1880, two people named Malherbe and Chenantais gave this condition its first name, “epithelioma,” because they thought it was connected to the oil glands in our skin. However, in 1961, Forbis and Helwing suggested a new name, pilomatrixoma, after discovering that the growth actually comes from the root of the hair.
Some medical experts suggest that this condition might affect more than just the root of the hair, involving other parts of the hair follicle too. These growths can influence aspects like the hair matrix (the part of the hair that actively grows), hair cortex (the middle layer of the hair), follicular infundibulum (the upper part of the follicle where it connects to the skin’s surface), outer root sheath (the outermost layer of the hair follicle), and hair bulge (a part of the hair follicle that plays roles in hair growth and re-growth).
Pilomatrixoma often happens in children, usually in places where hair grows on the head and neck, but it can also appear on the arms, legs, and torso. On the head, it most commonly shows up near the ear. It’s important to note that these growths only appear in places where hair grows. However, there have been cases where the growth has shown up in other parts of the body, such as around the eye, or on the scrotum or vulva.
What Causes Calcifying Epithelioma of Malherbe?
The exact reason why pilomatrixoma, a type of skin lesion, occurs is still unknown. However, it’s seen that in some cases, it can run in families, which indicates genetics may play a role. A very small number (3.9%) of cases have been linked to outside factors like injuries, insect bites, or surgery.
Risk Factors and Frequency for Calcifying Epithelioma of Malherbe
Pilomatrixomas, a type of skin condition, is generally found in children and typically appears on the head and neck. It’s rare in infants and usually begins around the age of 4.5 years. Most patients, about 90%, are under ten years old. There are two age groups where this condition is most common: between 0 to 20 years and 50 to 65 years. Slightly more females than males are affected, and it is more common in white individuals. Pilomatrixomas make up a very small percentage of skin conditions and are found in about 20% of all pilar lesions, another type of skin condition.
- Pilomatrixomas mainly affect children and often occur on the head and neck.
- The condition is rarely found in infants.
- The average age of onset is 4.5 years, and 90% of patients are less than ten years old.
- There are two main age groups where the condition is most common: 0 to 20 years and 50 to 65 years.
- The condition is slightly more common in females and white individuals.
- Pilomatrixomas represent a very small percentage (between 0.001% and 0.0031%) of all skin pathology samples.
- They constitute about 20% of all pilar lesions.
Signs and Symptoms of Calcifying Epithelioma of Malherbe
Pilomatrixomas are slow-growing tumors that typically appear beneath the skin. They’re known for being hard but moveable growths that are often enclosed in a fibrous shell. Over 70% of these tumors develop in the head and neck region, although they can grow elsewhere. While most pilomatrixomas tend to grow slowly, there have been instances of them growing rapidly.
Usually, a person will have only one pilomatrixoma, but it’s possible to have multiple. The skin above the tumor can sometimes look blue or red. This discoloration might even develop into a skin ulcer. For the most part, pilomatrixomas don’t cause symptoms. However, some people might feel pain or itching. If you stretch the skin over a pilomatrixoma, it might flatten out with a characteristic ‘tenting’ appearance.
A pigmented pilomatrixoma is a rare variation that contains cells called melanocytes, or melanin pigment. Some studies suggest that only 10% – or even less – of these tumors are pigmented, but a 2013 Japanese study reported an incidence of 24.6% among 53 Japanese patients.
There have been two reported instances where pilomatrixomas were associated with hair loss, or alopecia. One case involved a pilomatrixoma on the scalp that was surrounded by a patch of hair loss. In another case, a five-year-old Japanese girl had a pilomatrixoma on her left forehead. She experienced hair loss that affected her left eyebrow, but her hair began to grow back after the tumor was removed.
Testing for Calcifying Epithelioma of Malherbe
Pilomatrixoma is typically diagnosed through physical examination or through studying body tissues under a microscope. However, it’s often hard to correctly identify pilomatrixoma because many doctors aren’t familiar with the tumor and because it often looks like other types of skin conditions. Indeed, correct diagnosis only happens between 12.5% and 55.5% of the time.
Most of the time, we don’t use imaging techniques (like scans or X-rays) to diagnose this condition. But, in some cases, if your doctor wants to check for certain types of cancer in your blood vessels or lymphatic system, they might use imaging. This could involve an X-ray, a computerized tomography (CT) scan, or an ultrasound.
An ultrasound works by sending sound waves into your body. Different tissues inside your body reflect these sound waves back at different speeds. This allows the ultrasound machine to create an image of the inside of your body. In the case of pilomatrixoma, an ultrasound can help identify characteristics like mixed or varied textures, calcifications or hardening, a rim with low echo patterns, and a shadow behind the lesion. Using these indicators, ultrasounds can correctly diagnose pilomatrixoma in 76% of cases before surgery. That’s a big improvement compared to a 33% success rate when the diagnosis was made through physical examination alone.
Treatment Options for Calcifying Epithelioma of Malherbe
Pilomatrixomas are non-cancerous tumors that doctors usually monitor without any further treatment, unless they start to grow or cause pain. If needed, the best course of treatment is surgical removal. There is a small risk (2-6%) that the tumor will come back, usually because it wasn’t entirely removed the first time. There are no obtained guides or rules on how wide the surgical incision should be.
In some rare cases, pilomatrixomas can become malignant or cancerous, transforming into tumors known as “pilomatrix carcinomas.” Only about 125 cases of this transformation have been reported. One can suspect this transformation if the tumor cells appear oddly shaped (pleomorphism), divide rapidly (high mitotic rate), look abnormal (atypia), have areas of dying tissue (central necrosis), and invade nearby skin, soft tissue, blood, and lymph vessels extensively. This transformation is more common in men aged between 50 to 70. In one rare case, it occurred in a child. These tumors usually appear as firm, non-painful lumps on the head or neck. Pilomatrix carcinomas can advance and spread to other parts of the body, known as metastasis, in about 10% of cases. If it comes back after treatment (recurrence), that could mean it’s more likely to spread. The most common site for these tumors to spread is the lungs.
When treating this type of cancerous tumor, doctors usually use a surgical approach that involves removing a good part of the healthy tissue around the tumor. However, it has a high chance of returning (50-60%). If the tumor is persistent or has spread, radiation therapy or chemotherapy is often used as additional treatment.
On some occasions, people may have more than one pilomatrixoma. This occurrence is usually linked with conditions like myotonic dystrophy, Familial adenomatous polyposis, Gardner syndrome, Turner syndrome, xeroderma pigmentosum, Rubinstein-Taybi syndrome, Sotos syndrome, and basal cell nevus syndrome.
What else can Calcifying Epithelioma of Malherbe be?
When a doctor is trying to diagnose a condition, they have to think about all the other conditions that could cause the same symptoms. So, when it comes to diagnosing a skin or tissue condition, they may have to rule out the following possibilities:
- Sebaceous and epidermoid cysts (skin lumps filled with pus or fluid)
- Epitheliomas (a type of skin cancer)
- Neurofibromas (tumors in nervous tissue)
- Foreign body reactions (reactions to substances that shouldn’t be in the body)
- Calcified cysts or hematomas (hard lumps or bruises in the skin or tissue)
- Chondromas (non-cancerous tumors in cartilage)
- Fibroxanthomas (benign tissue growths)
- Osteoma cutis (bone growth in the skin)
- Giant cell tumors (a tumor that often occurs in bones)
