Superficial fibromatosis

by Bibianna Purgina, MD FRCPC
May 3, 2022

What is superficial fibromatosis?

Superficial fibromatosis is a non-cancerous tumour made up of a specialized type of connective tissue called fibrous tissue. There are other names for superficial fibromatosis, based on where in the body it develops. When this condition develops in the palm of the hand it is called Dupuytren’s contracture or palmar fibromatosis. In this location, it can form hard bumps on the palm of the hand and puckering of the skin. This can make it difficult to extend your fingers. Dupuytren’s contracture is more common in older patients and can affect both hands. When this condition develops on the bottom of the foot (the sole) is called plantar fibromatosis or Ledderhose’s disease. This condition can also involve the penis and is called penile fibromatosis or Peyronie’s disease. Penile fibromatosis typically affects men over the age of 40.

How do pathologists make the diagnosis of superficial fibromatosis?

The diagnosis of superficial fibromatosis is usually made after the tumour is removed in a procedure called an excision.  The tissue is then sent to a pathologist who examines it under a microscope. In most cases, additional tests such as immunohistochemistry or molecular testing are not needed to confirm the diagnosis.

superficial fibromatosis

The microscopic appearance of superficial fibromatosis.

What does superficial fibromatosis look like under the microscope?

All types of superficial fibromatosis are benign (non-cancerous) tumours and they all look very similar when viewed under the microscope.  The challenge for pathologists in making this diagnosis is that the tumour cells of superficial fibromatosis look very similar to the cells that make up normal fibrous tissue. These cells are called fibroblasts and myofibroblasts. However, unlike normal fibrous tissue, the cells in this tumour form small round structures that pathologists call nodules. These nodules can be seen under the microscope which allows your pathologist to make the correct diagnosis.

The number of these fibroblasts and myofibroblasts cells in the tumour changes depending on how long the tumour has been there.  Usually, tumours that have been there for a long time have fewer cells. Pathologists describe these tumours as hypocellular. In contrast, tumours that have a larger number of cells are called cellular.

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