Muscle biopsies are undertaken to investigate myopathy and neurogenic atrophy using a range of diagnostic techniques. Specimens may be received in clamps to prevent muscle contraction. Electron microscopy is generally required on a portion of the tissue.1-4
Record the patient identifying information and any clinical information supplied together with the specimen description as designated on the container. See overview page for more detail on identification principles.
Clinical information for any muscle biopsy should include the following (a standard proforma for clinicians is useful in ensuring that this information is recorded):
- Information about the biopsy site and laterality
- Age at biopsy (essential)
- Details of onset, distribution and progression of the disorder
- Involvement of other organs
- Results of nerve conduction studies and electromyography or MRI of brain, spinal cord and adjacent nerve roots or muscle (if performed)
- Drug history
- Occupational exposure/s
- Past and current personal and family medical history
- Plasma creatinine kinase (CK) level (essential)
- Plasma and CSF lactate levels, other biochemical investigations and results of brain, spinal cord and adjacent nerve roots or muscle MRI (if performed).
- Non-routine fixation (not formalin), describe.
- Special studies required, describe.
- Ensure samples are taken prior to fixation.
- Samples for electron microscopy should be fixed in glutaraldehyde within 15 minutes of being taken.
- Samples collected for mitochondrial respiratory chain enzyme analysis must be frozen immediately.
If total transit time from taking muscle biopsy to receipt at a specialist centre is <2hours
- Muscle biopsies must ideally be transported immediately to the lab fresh at room temperature, in a manner that prevents the specimen drying out. One method is to request that the tissue be put into a sterile container without any wrapping or liquid. While some centres place the specimen into lightly moistened gauze, this may absorb moisture out of the specimen. Another suggested method is to wrap the specimen in cling film.
If total transit time from taking muscle biopsy to receipt at a specialist centre is >2hours
- Specimens must be frozen on site and transported on dry ice.
See general information for more detail on specimen handling procedures.
Inspect the specimen and dictate a macroscopic description.
Orientate and identify the anatomical features of the specimen.
Record additional orientation or designation provided by operating clinician:
- Method of designation (e.g. suture, incision)
- Featured denoted
Photograph the intact specimen if required.
Describe the following features of the specimen:
Record as stated by the clinican.
- Needle biopsy
- Open biopsy
- Other tissue present
Specimen size (mm) of each fragment1
- In two dimensions, length x diameter
- Fragmented, describe
Clamps are not always utilised. A free piece of tissue without any adherent fascia is an adequate specimen.
- Orientate under a dissecting microscope to ensure transverse sections of the muscle fibres can be obtained.3
- Dissect a 1-2mm longitudinal segment for electron microscopy1,2,4 and transfer to a suitable fixative such as 2.5% buffered glutaraldehyde.
- Submit the remaining tissue for frozen sections; usually two blocks
- Tissue from frozen sections can be utilised for molecular biology or biochemical analysis if required.
Any excess tissue (not required for electron microscopy) may be submitted in its entirety for processing into paraffin sections.1,2 Lens paper, biopsy pads or similar are required to prevent loss of tissue during processing.
However paraffin embedded tissue produce less than optimal diagnostic morphological detail than frozen sections and are generally not required.
Record details of each cassette.
An illustrated block key similar to the one provided may be useful.
Block allocation key
No. of pieces
Dr Barbara Koszyca and Kathy Cash for their contribution in reviewing and editing this protocol.
Dubowitz V and Sewry CA. Muscle Biopsy. A practical approach Saunders Elsevier, China, 2007.
C. Sundaram and Megha S. Uppin. Approach to the Interpretation of Muscle Biopsy, Dr. Challa Sundaram (Ed.)
, 2012, ISBN: 978-953-307-778-9, InTech, Available here
Lester SC. Manual of Surgical Pathology, Saunders Elsevier, Philadelphia, 2010.