Giant cell tumour of tendon sheath

This article will help you read and understand your pathology report for giant cell tumour of tendon sheath.

by Osama Khan MD and Bibianna Purgina MD FRCPC, reviewed on May 3, 2020

giant cell tumour of tendon sheath

Quick facts:

  • Giant cell tumour of tendon sheath is a common type of non-cancerous tumour.
  • They are painless and slow growing.
  • The most common location for this tumour is the hand but they can also involve other parts of the body.
  • Although giant cell tumours of tendon sheaths are non-cancerous, a small number can grow back again in the same spot.

Normal tendons

Tendons are tough bands of tissue that connect a muscle to bone and are important for movement. Tendons are similar to ligaments which connect two bones together and are important for stability. Tendons are covered and protected by a thin layer of tissue called a tendon sheath. The tendon sheath is filled with lubricating fluid that allow tendons to move smoothly and freely.

What is a giant cell tumour of tendon sheath?

Giant cell tumour of tendon sheath is a non-cancerous tumour that commonly occurs in the fingers of the hand. It can also involve the large joints of the body such as the knee and elbow. Joints connect two bones together and are important for movement.

This tumour most commonly affect people in their 30s and 40s and occur more commonly in females.

Although a giant cell tumour of tendon sheath is non-cancerous, a small number of them can grow back at the the same location over time.

How do pathologists make this diagnosis?

Giant cell tumour of tendon sheath are typically diagnosed after a small sample of tissue is removed in a procedure called a biopsy or they are completely removed in a procedure called an excision or resection. They are then examined by a pathologist under the microscope.

The tumour is made up of two kinds of cells:

  1. Mononuclear cells – These are small round cells with a single nucleus. The nucleus is the part of the cell that holds most of the cells’ genetic material (DNA).
  2. Osteoclast-like giant cells – These are very large cells that have more than one nucleus.

Your pathologist will look for both of these types of cells when examining your tissue sample under the microscope.

If the diagnosis was made after a biopsy, you may undergo another surgery to remove the tumour completely. After the tumour is removed completely it will be sent to pathology where a pathologist will examine the tissue to confirm the original diagnosis.

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