When most people hear the word tumor, they think cancer. But not all tumors are cancerous; the medical definition of a tumor is merely “an abnormal growth of tissue.“

Tumors, also known as neoplasms, are classified as either benign or malignant (i.e., cancerous), and there are several distinct types of tumors that can affect the toes and toenails.

Some of these toenail tumors are harmless and easily treated, while others are cause for serious concern. Some of them can permanently alter the shape or appearance of the nail plate (what you probably think of as “the nail”), or even destroy it.

Some of these tumors even have the potential to spread and become life threatening.

In this article we will discuss some of the various types of toenail tumor, and we will attempt to dispel some of the anxieties that may arise if you should happen to be diagnosed with one of them.

Onychomatricoma

Onychomatricoma is a tumor of the nail matrix that most often occurs in middle age. This type of tumor is generally benign, but it has the potential to become malignant.

Onychomatricoma may be accompanied by alarming symptoms—long, finger-like projections may appear throughout the nail, causing the nail to thicken and become grooved.

Yellow discoloration of the toenail with multiple cavities (holes) at the distal (far) margin of the nail may also occur.

Onychomatricoma is a rare condition that was not even described in medical literature prior to 1992. Due to its rarity it has not been well studied, and the exact cause of onychomatricoma tumors is therefore not known.

It is possible that they may be related in some way to fungal infections of the toenail, which appear in roughly half of all cases. It is also possible that heredity may play some role, as there is a notably greater incidence among Caucasians than among other races.

Most patients do not report the occurrence of any trauma or injury in conjunction with their tumor. Diagnosis is obtained by a simple clipping of the end of the nail (as opposed to the base of the nail), which will show multiple cavities filled with serous fluid.

Warts

Warts are the most common benign non-cancerous type of tumor, and they are caused by the human papillomavirus (HPV), which affects the skin.

While warts are most commonly seen in the plantar region (the bottom of the foot), they can also appear on the skin surrounding the toenails, or in some cases, even beneath the nail plate.

Treating a wart underneath the nail may require avulsion (removal) of the nail plate itself (a procedure described in more detail here).

Many other types of skin lesions, even including malignant lesions like squamous cell carcinoma or malignant melanoma, can look like warts. This is exactly why it is essential to see your doctor about any suspicious lesions on your feet.

The best diagnostic aid is excision and histologic analysis of the lesion itself to rule out any possibility of malignancy. Treatments are various and include cryotherapy, laser therapy, chemical ablation, and surgical excision.

Glomus Tumor

A glomus tumor is yet another type of benign tumor—although it should be noted here that the word benign, when used in a medical terminology, does not necessarily mean “harmless.”

On the contrary, glomus tumors, like many benign growths (especially under the nail plate) can be quite painful.

While these types of tumors often appear under the nail, they can also appear elsewhere in the foot or elsewhere on the body. Regardless of where they appear, glomus tumors are tender to the touch and extremely sensitive to cold; even cold tap water can be excruciatingly painful.

Glomus tumors arise from glomus bodies, which control shunting of blood for temperature regulation. Clinically, a glomus tumor may appear as a tender, red, subungual (beneath the nail) nodule or as a small, subtle area of blue pigmentation.

A pulsating pain is the most common complaint. Surgical excision is typically required for treatment.

Cancer

While most toenail tumors are not life threatening (even if they are painful), some turn out to be malignant. Most of us are accustomed to the idea that we need to keep an eye on our skin and notice when new moles appear, or when existing moles change in size or shape.

But it is important to remember that the skin under our fingernails and toenails is also susceptible to malignant tumors. The most common malignant tumors that affect the nail matrix and nail bed are melanomas.

This type of cancer affects the thumb, index finder, and big toe more often than it strikes any other toe or finger. The easiest warning sign to spot is a dark, longitudinal stripe running from the nail fold to the tip of the nail. This should be cause for special concern if:

• The stripe has soft, blurry edges
• It is very dark or black
• Its appearance changes over time
• The base of the stripe is wider and narrows as it progresses up the nail

The appearance of this kind of stripe on your nail should be cause for particular concern if there is cancer in your family’s medical history.

However, it is also important to keep in mind that amelanotic melanoma (lack of pigmentation) is also very common. Therefore, it is safest to have any unusual lesion examined by your physician. People of African descent are more susceptible to toenail cancer than people of other ethnic backgrounds; in fact, reggae legend Bob Marley died from cancer that began under his toenail (melanoma).

Unwilling for religious reasons to heed his doctor’s recommendation that the toe be amputated, Marley sought other, less medically sound remedies, and his toenail cancer took his life.

Diagnosis of Toenail Tumors – What to Expect When Visiting Your Doctor

Because some types of tumors under the toenail can be initiated by trauma, they can in some cases go unreported and undiagnosed for months.

The reason for this is that the affected person mistakes the pain and discoloration for a bruise under the nail, only seeking treatment when the mark does not go away for months, or when they begin to experience other symptoms.

The web site LiveScience recently reported the story of a man in his forties who noticed a two-millimeter-wide dark blue line running the length of his nail after an injury. Assuming that it was merely a splinter (the nail had thickened, adding to the appearance of a foreign object under it), the man did nothing for three years.

When he finally sought medical attention, however, the line turned out to be onychocytic matricoma, another type of benign nail matrix tumor. After the tumor’s removal, there was no further trouble related to it. The key to diagnosis is a biopsy by your physician.

If you notice any sort of inexplicable growth or discoloration under your nail, you should see a doctor as soon as possible to have it examined. Not all toenail tumors turn out to be benign.