Nodular fasciitis is a rare, noncancerous tumor. It can appear in soft tissue anywhere on your body.

Nodular fasciitis mimics malignant (cancerous) tumors, which makes it a challenge to diagnose. Accurate diagnosis is important to avoid an unnecessary treatment for a mistaken cancerous growth.

Nodular fasciitis is usually:

  • small, typically under 1.18 inches (3 centimeters)
  • solitary
  • fast-growing
  • occasionally a little painful

The cause of nodular fasciitis isn’t known. It may also be called pseudosarcomatous fasciitis, proliferative fasciitis, or infiltrative fasciitis.

Nodular fasciitis most often occurs in adults 20 to 40 years old, but it can also occur at other ages. It affects males and females with equal frequency.

Did you know?Fasciitis refers to an inflammation of the fascia, the connective tissue under your skin that surrounds muscles, blood vessels, and nerves. The word comes from the Latin fascia, which means band or bandage.

Treatment options for nodular fasciitis depend in part on the size and location of the tumor. Some tumors may resolve on their own. In an older study, 9 out of 11 tumors resolved on their own in three to eight weeks after fine needle aspiration cytology (FNAC). Other research has reported a similar result.

Observation

You and your doctor may decide to do nothing about the tumor other than monitor it.

Surgery

The usual treatment is surgical removal. The surgery may involve total or partial removal of the tumor mass.

In virtually all cases, the tumor doesn’t recur after surgery.

Pinhole laser

A carbon dioxide (CO2) laser used in a pinhole pattern is a treatment option for tumors on the face or another area where you don’t want scarring. Malignancy (cancer) should be ruled out before this treatment.

Corticosteroids

If the nodular fasciitis is large or on the face, a corticosteroid injection at the site may help resolve the tumor.

A 2015 article reported that this nonsurgical treatment for facial tumors produced better results with fewer recurrences. Malignancy should be ruled out before this treatment.

Histology refers to the particular kinds of cells in a tumor. These can be seen by looking at tumor tissue under a microscope. Malignant tumors and nodular fasciitis sometimes have similar cell populations.

Under a microscope, cells in nodular fasciitis tissue float around in loose bundles of:

  • fibroblasts, spindle-shaped cells found in connective tissue
  • myofibroblasts, large cells with an appearance between fibroblasts and smooth muscle tissue

The cell bundles move within a mucous-like matrix called a myxoid stroma.

The following are other characteristics of nodular fasciitis tissue:

  • The bundles of cells form “S” or “C” shapes when they move around, or sometimes cartwheel formations.
  • Cells have a feathery appearance, with holes or tears in the tissue.
  • Chromosomes of the cells are visible during cell division.
  • The chromosome material (chromatin) is fine, pale, and even-looking.
  • Cells don’t change their shape (non-pleomorphic).
  • Cells have a high rate of division (mitosis).

Researchers may stain the cells to examine their structure and reactivity. Some of the nodular fasciitis cell characteristics may change, depending on the location of the tumor.

The histology is important for diagnosis. In contrast, a malignant sarcoma usually:

  • is larger than 4 centimeters
  • has cells that change shape (pleomorphic)
  • has coarse, granular, and irregular chromosome material
  • has abnormal cell division

Nodular fasciitis is a small soft-tissue tumor under the skin with these characteristics:

  • It grows very rapidly.
  • It’s a solitary tumor.
  • It feels firm.
  • It's usually not painful.
  • It may be tender.
  • It doesn’t spread.
  • It’s oval or round in shape with irregular margins.

There’s nothing in its appearance to distinguish it from a malignant tumor.

The cause of nodular fasciitis isn’t known. It’s thought that the tumors might occur after an injury to the area or an infection.

Nodular fasciitis can occur anywhere in the body, including the mouth. The most frequent sites, according to a 1984 review of 250 cases, are:

  • forearm (27 percent)
  • thigh (17 percent)
  • upper arm (12 percent)

A 2017 study presented similar figures:

  • arms (34 percent)
  • head and neck region (24 percent)
  • trunk (21 percent)
  • legs (14 percent)

Diagnosis of nodular fasciitis is a challenge because it’s similar to some malignant tumors. It’s also very rare. It represents only 0.025 percent of all tumor cases.

Nodular fasciitis can resemble:

  • spindle cell sarcoma
  • fibromatosis
  • fibrous histiocytoma
  • benign nerve sheath tumors
  • pleomorphic adenoma

Imaging by sonogram, MRI scan, or CT scan can help characterize features of nodular fasciitis. FNAC followed by an analysis of tissue histology can help make a definitive diagnosis. Sometimes the diagnosis isn’t confirmed until the tumor is surgically removed.

Nodular fasciitis is a harmless tumor with an excellent outlook. Sometimes it resolves without any treatment.

The tumor resolves with surgery, including partial surgery.

Some tumors may be treated with corticosteroids. Steroid injection is a successful method if the tumor is on the face and aesthetics are involved.

If you have any symptoms of this type of tumor, it’s important that you talk to a doctor right away. Although such tumors are harmless, they share many characteristics with cancerous tumors, so it’s important to get a diagnosis.