Diagnosis of rhabdomyosarcoma

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Diagnosis is the process of finding out the cause of a health problem. Diagnosing rhabdomyosarcoma (RMS) usually begins with a visit to your child's family doctor or pediatrician. The doctor will ask you about any symptoms your child has and will do a physical exam. Based on this information, the doctor may refer your child to a specialist or order tests to check for RMS or other health problems.

The process of diagnosis may seem long and frustrating. It's normal to worry, but try to remember that other health conditions can cause similar symptoms as RMS. It's important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of RMS.

The following tests are usually used to rule out or diagnose RMS. Many of the same tests used to diagnose cancer are used to find out the stage (how far the cancer has spread). The doctor may also order other tests to check your child's general health and to help plan their treatment.

Health history and physical exam

Health history is a record of your child's symptoms and risks and all the medical events and problems your child has had in the past. The doctor will ask questions about a personal or family history of certain genetic conditions, including:

  • Li-Fraumeni syndrome
  • neurofibromatosis type 1 (also known as von Recklinghausen disease)
  • Beckwith-Wiedemann syndrome
  • Costello syndrome
  • Noonan syndrome

A physical exam allows the doctor to look for any signs of RMS. During a physical exam, your child's doctor may:

  • check for any swelling or lumps
  • look at and feel any lumps to check their size and to see if they move or are attached to tissues under the skin, such as muscle or bone
  • feel the lymph nodes near any lumps

Find out more about physical exams.

Complete blood count (CBC)

A complete blood count (CBC) measures the number and quality of white blood cells, red blood cells and platelets. A CBC is done to check if cancer has spread to the bone marrow.

Find out more about a complete blood count (CBC).

Blood chemistry tests

Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are working and can help find abnormalities. Blood chemistry tests are used to check how well the liver and kidneys are working.

Find out more about blood chemistry tests.

CT scan

A computed tomography (CT) scan uses special x-ray equipment to make 3D and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures.

A CT scan is used to see tumours in the chest, abdomen, pelvis or lymph nodes. It can also be used to:

  • find out how large the tumour is
  • find out if the tumour has grown into nearby areas
  • see if cancer has spread to lymph nodes near the tumour
  • see if cancer has spread to other organs or tissues, such as the lungs

Find out more about CT scans.

X-ray

An x-ray uses small doses of radiation to make an image of parts of the body on film. A chest x-ray is sometimes done to see if cancer has spread to the lungs. If a CT scan of the chest is done, doctors usually won't do a chest x-ray as well.

Find out more about x-rays.

MRI

Magnetic resonance imaging (MRI) uses powerful magnetic forces and radiofrequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3D pictures.

An MRI is used for tumours in the head and neck area, arms, legs or pelvis. It is used to:

  • find out how large the tumour is
  • find out if the tumour has grown into nearby areas
  • show the muscle, fat and connective tissue around the tumour, which helps doctors plan surgery or radiation therapy
  • check if the cancer has spread to other parts of the body, such as lymph nodes near the tumour, the spinal cord or the brain

Find out more about MRIs.

PET scan

A positron emission tomography (PET) scan uses radioactive materials called radiopharmaceuticals to look for changes in the metabolic activity of body tissues. A computer analyzes the radioactive patterns and makes 3D colour images of the area being scanned.

A PET scan may be used to:

  • tell RMS from a non-cancerous tumour in a muscle
  • check if cancer has spread to other areas of the body

Some imaging machines can do a PET scan and a CT scan at the same time (called PET-CT scan). This helps doctors see in better detail areas with higher metabolic activity.

Find out more about PET scans.

Ultrasound

An ultrasound uses high-frequency sound waves to make images of parts of the body. It may be used to look at tumours in the abdomen or pelvis.

Find out more about ultrasounds.

Bone scan

A bone scan uses radioactive materials called radiopharmaceuticals and a computer to create a picture of the bones. It is used to see if cancer has spread to the bones.

Find out more about bone scans.

Biopsy

During a biopsy, the doctor removes tissues or cells from the body so they can be tested in a lab. A report from a pathologist will show whether or not cancer cells are found in the sample.

A surgical biopsy removes a piece of the tumour by cutting through the skin. The doctor may also remove lymph nodes near the tumour to see if cancer has spread to them. Your child will be asleep under general anesthesia during a surgical biopsy.

A core needle biopsy uses a needle to remove a small sample of the tumour. If the tumour is deep inside the body, the doctor may use an ultrasound or CT scan to guide the needle into the tumour.

A fine needle aspiration (FNA) biopsy uses a thin needle and a syringe to remove a small amount of fluid or cells. An FNA works best with tumours that are just under the skin and can be easily reached with the needle.

Find out more about biopsies.

Bone marrow aspiration and biopsy

A bone marrow aspiration and biopsy removes tissues or cells from the bone marrow. Doctors use it to see if cancer has spread to the bone marrow.

Find out more about a bone marrow aspiration and biopsy.

Lumbar puncture

A lumbar puncture removes a small amount of cerebrospinal fluid (CSF) from the spine. CSF surrounds and helps protect the brain and spinal cord. The fluid removed during a lumbar puncture is examined under a microscope to see if cancer has spread to the central nervous system (CNS). A lumbar puncture may be done if the tumour is near the tissue surrounding the brain and spinal cord (called the meninges). A lumbar puncture may also be called a spinal tap.

Find out more about lumbar punctures.

Questions to ask the healthcare team

To make the decisions that are right for your child, ask the healthcare team questions about a diagnosis.

Expert review and references

  • Paul Nathan, MD, MSc, FRCPC
  • Normand Laperriere, MD, FRCPC
  • PDQ® Pediatric Treatment Editorial Board . Childhood Rhabdomyosarcoma Treatment (PDQ®) – Health Professional Version . Bethesda, MD : National Cancer Institute ; 2020 : https://www.cancer.gov/.
  • American Cancer Society. Rhabdomyosarcoma Early Dectection, Diagnosis, and Staging. 2018: https://www.cancer.org/.
  • American Society of Clinical Oncology (ASCO). Cancer.net: Rhabdomyosarcoma - Childhood: Diagnosis. 2018: https://www.cancer.net/.
  • Rhabdomyosarcoma. Provincial Health Services Authority. Musculoskeletal and Sarcoma. Vancouver, BC: http://www.bccancer.bc.ca/. Friday, March 20, 2020.
  • Cripe TP . Medscape Reference: Pediatric Rhabdomyosarcoma. WebMD LLC; 2018: https://www.medscape.com/.
  • Wexler LH, Skapek SX, Helman LJ. Rhabdomyosarcoma. Pizzo PA, Poplack DG, eds.. Principles and Practice of Pediatric Oncology. 7th ed. Philadelphia, PA: Wolters Kluwer; 2016: 31:798–827.