Superficial fibromatosis

by Bibianna Purgina, MD FRCPC
April 24, 2023

What is superficial fibromatosis?

Superficial fibromatosis is a non-cancerous tumour made up of a specialized type of connective tissue called fibrous tissue.

What are the types of superficial fibromatosis?

Palmar fibromatosis

Palmar fibromatosis is a type of superficial fibromatosis that affects the palm (inside surface) of the hand. It is also called Dupuytren’s contracture. Palmar fibromatosis is more common in older patients and can affect both hands.

Plantar fibromatosis

Plantar fibromatosis is a type of superficial fibromatosis that affects the bottom (sole) of the foot. It is also called Ledderhose’s disease.

Penile fibromatosis

Penile fibromatosis is a type of superficial fibromatosis that affects the penis. It is also called Peyronie’s disease. Penile fibromatosis typically affects men over the age of 40.

What causes superficial fibromatosis?

At this time, the cause of superficial fibromatosis remains unknown.

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
Superficial fibromatosis. The tumour is made up of long thin spindle cells in a pink fibrotic stroma.

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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