What is Poroma?
A poroma (also known as a poroid tumor) is a benign tumor, meaning it is not cancerous, that generally comes from the sweat gland’s ending duct. This information was first detailed by Pinkus and his team in 1956. At first, they thought that the poroma stemmed from what is known as an eccrine origin. But more recent studies have shown that this growth can also come from other types of glandular tissue in the skin, including apocrine, sebaceous, and follicular.
Some medical experts refer to this growth as an “acrospiroma,” while others think of the poroma as a larger group of skin growths. This group includes nodular hidradenomas, clear cell hidradenomas, hidroacanthoma simplex, dermal duct tumors, and hidradenoma. Even though it’s benign, a poroma can exhibit potential degeneration. In some cases, a poroma can turn into porocarcinoma, a malignant or cancerous tumor, if it’s left alone for several years.
What Causes Poroma?
We’re unsure what exactly triggers the growth of poromas, which are harmless tumors that develop in sweat glands. Unlike other types of tumors that develop in hair follicle-related tissue, a family history of the condition doesn’t seem to increase your risk of developing poromas. Some believe that being exposed to radiation consistently over a long period of time could be a contributor to the development of both poromas and a rare form of malignant (cancerous) poroma called porocarcinomas.
Poromas have also recently been linked to chronic radiation dermatitis, which is skin inflammation caused by prolonged exposure to radiation.
While it’s known that porocarcinoma can develop from a benign (harmless) poroma, it’s unclear how this process actually happens and how long it typically takes. Factors like having a weakened immune system, exposure to harmful chemicals, and constant exposure to light could all increase your risk of developing porocarcinoma.
Poromas have occasionally been reported in people with other conditions like “Bowen disease”, which is an early form of skin cancer and “hypohidrotic ectodermal dysplasia”, a group of conditions that can impact hair, sweat glands, and teeth.
Reports have shown that porocarcinomas occur more commonly with certain conditions, like “xeroderma pigmentosum”, an inherited condition that makes people highly sensitive to sunlight; “extra-mammary Paget’s disease”, a rare skin cancer that usually affects the genital region; and other conditions that affect the immune system like “Hodgkin’s lymphoma”, “chronic lymphocytic leukemia”, pernicious anemia, sarcoidosis, and HIV infection.
Risk Factors and Frequency for Poroma
Sweat gland tumors make up about 1% of primary skin lesions, but specifically, eccrine and apocrine poromas make up about 10%. It’s important to understand that poromas don’t favor any ethnicity or race, and they can affect both men and women equally. These can occur at any age but usually appear in adulthood.
Eccrine porocarcinoma, a type of skin cancer, has a lower rate than poroma, comprising just 0.005% of epithelial skin growths. This condition is more common in older individuals. In a 2017 research study looking at 453 patients diagnosed with eccrine porocarcinoma, the patients’ demographics were almost evenly split, with 49% male and 51% female ranging in age from 6 months to 97 years.
Signs and Symptoms of Poroma
Poroma is a skin condition that usually appears as a single, slow-growing small bump or patch that might be skin-colored, red, brown, or blue. These growths, while generally painless, can sometimes be slightly tender to touch. They often look like small, blood vessel-rich skin growths, similar in look to a pyogenic granuloma.
These skin growths are most commonly found on the palms and soles but can appear on any part of the body. Some less common locations include the head, neck, torso, armpits, upper limbs, buttocks, and lower limbs. In some rare instances, a poroma may occur within a sebaceous nevus, which is a type of skin lesion.
Another type of poroma, known as apocrine poroma, has similar appearances but is never found on the palms or soles. Instead, it tends to appear on the face, body and limbs. When multiple poromas appear on the body, this is referred to as “poromatosis,” which can sometimes occur after chemotherapy or radiotherapy.
Occasionally, poroma can transform into a porocarcinoma, which is a rare type of skin cancer. Indications of this transformation include recurrent open sores, bleeding, sudden growth, or sudden pain in a preexisting growth. The most common sites for porocarcinoma are the head and neck followed by the lower extremities.
Testing for Poroma
When it comes to diagnosing a skin condition called poroma, a visual examination of your skin by a doctor is very important. However, a tool known as a dermoscope can provide more insight. Dermoscopy is a technique of examining the skin using skin surface microscopy, and it is used to evaluate skin conditions. With poroma, dermoscopy can show features like branched blood vessels with rounded ends, white criss-cross areas around blood vessels, yellow areas with no structure, and red globules resembling drops of milk.
Dermoscopy can also help distinguish between poroma, which is generally benign, and a more dangerous skin cancer known as porocarcinoma. With porocarcinoma, dermoscopy might reveal pinkish-white, structureless areas surrounded by lighter halos while with poroma, similar areas would be more widespread, reminding us of a “frog-eggs” pattern.
The most surefire way of diagnosing poroma is through a biopsy, a procedure in which the doctor takes a small sample of the skin to examine under a microscope. Doctors will also be cautious about the possibility of porocarcinoma, which is a malignancy or cancer. In cases with suspicion of porocarcinoma, they will investigate the status of the nearby lymph nodes and look for signs of metastases, which is a term for cancer that has spread to other parts of the body. Diagnosing porocarcinoma can indeed be tricky, as it may look similar to other skin cancers or even a benign poroma under the microscope. In such cases, additional tests with special stains may be used to accurately identify the condition.
Treatment Options for Poroma
A poroma is a type of benign, non-cancerous skin growth known as an adnexal neoplasm. Treatment is entirely optional due to its benign nature, but if you choose to remove it, it can generally be done quite effectively. For deeper lesions, a simple surgical procedure to remove the growth is often enough. For more superficial lesions, electrosurgical destruction, which uses electricity to destroy the lesion, may work.
Porocarcinoma, on the other hand, is a more serious condition and requires more intensive treatment options. These can include Mohs micrographic surgery, which is a precise surgical procedure used to treat skin cancer. Other options include standard surgical removal of the growth with wide margins around it to ensure all the cancerous cells are removed, radiation therapy which uses high-energy rays or particles to kill cancer cells, and chemotherapy, which is the use of drugs to kill cancer cells.
It’s worth noting that some experts believe Mohs micrographic surgery is the best treatment option for porocarcinoma. This is because it aims to remove all cancer cells without causing unnecessary damage to the surrounding healthy tissue, reduces the risk of the cancer spreading elsewhere in the body, and ensures all the boundaries around the tumor are cancer-free.
What else can Poroma be?
Poromas, a type of skin tumor, can often be misidentified as other skin conditions because their symptoms can be very similar. In one study, prior to receiving the correct diagnosis of eccrine poroma, some patients were mistakenly diagnosed with:
- Pyogenic granuloma
- Soft fibroma
- Verruca vulgaris (common warts)
- Hemangioma (blood vessel growths)
- Pigmented nevus (moles)
- Basal cell carcinoma (a type of skin cancer)
Other possible conditions that a poroma could be mistaken for include squamous cell carcinoma, seborrheic keratosis, hidradenomas, trichilemmoma, and other adnexal tumors (growths that develop in the organs associated with hair, nails, sweat glands, etc).
Persistent or long-standing tumors on the limbs and head, such as squamous cell carcinoma, Paget disease, basal cell carcinoma, and hidradenocarcinoma melanoma, have similar symptoms to inflamed poroma and metastatic cancer porocarcinoma. If porocarcinoma occurs in the nail fold, it might look like an ingrown toenail.
Determining whether a tumor is an apocrine poroma (a specific type of poroma) can be challenging when looked at under a microscope. This type of poroma shows a mix of apocrine (related to certain sweat glands), sebaceous (related to oil glands), and follicular (related to hair follicles) features within what would otherwise be typical poroid tumors. There have been cases reported where apocrine poroma coexists with basal-cell epithelioma (another type of skin cancer) and eccrine poroma, and even cases where it occurs with other types of skin tumors.
What to expect with Poroma
Poromas are skin conditions that often have a good outcome. They may appear as single bumps or small growths on your skin. Most of the time, these skin changes don’t cause any discomfort, though some might be a bit tender. In some cases, people can have many poromas all at once — this is known as “porokeratosis.” Having more than one poroma can be concerning for how it looks.
The chance of a poroma changing into a more harmful skin cancer known as porocarcinoma is very low. In a study by Salih and his team, it was found that in 31% of cases, the cancer had spread by the time it was noticed. The cancer most often spread to nearby lymph nodes (small organs that filter harmful substances from your body) at 57.7%, then to the respiratory tract or lungs (12.8%), the brain (9%), the liver (9%), the skin (5.8%), bones (3.2%), the stomach (0.6%) and the breast (0.6%). A spread to multiple areas, called “disseminated metastasis,” was found in 1.3% of cases.
Possible Complications When Diagnosed with Poroma
Poroma is a harmless condition, which does not typically come with its own specific complications. However, after surgical procedures, it’s not uncommon for problems like infections or bleeding to come up.
Common complications following surgery:
- Infections
- Bleeding
Preventing Poroma
A poroma is usually a harmless growth or tumor that often doesn’t cause any symptoms and is typically not dangerous. Normally, there’s no need for patients to worry about the tumor becoming malignant (cancerous), like with porocarcinoma, because the risk is about the same as for normal skin. However, a condition known as poromatosis can cause changes in appearance that some people might find unpleasant. Also, if it occurs on the soles of the feet, it could make walking or doing other activities more difficult.
