Brain biopsy including pituitary

Background

Brain biopsies are undertaken for the investigation of primary and metastatic tumours as well as vascular malformations. Less commonly histology may be required for focal infections and diffuse diseases such as dementia and lymphoma. 1,2

Hypophysectomy is the removal of the pituitary gland (hypophysis). Surgery aims to preserve pituitary gland tissue and only resect tumour. Invasion of adjacent brain is associated with increased recurrence.1

Intraoperative consultation may be required to ensure that diagnostic tissue is present in the sample and for preliminary diagnosis. These may be in the form of cytology specimens (smears and squash preparations). 1

See separate protocol for brain tumour resection specimens.


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.

Fresh tissue received
  • No
    • Non-routine fixation (not formalin), describe.
  • Yes
    • Special studies required, describe.
    • Ensure samples are taken prior to fixation.

Fresh unfixed tissue should be handled in appropriate extraction cabinets and with suitable personal protection equipment for infection control. Where sufficient material is available, unfixed specimens may be sampled for special studies using a fresh, sterile blade and distributed to appropriate laboratories (internal and external). These may include frozen sections, imprints, flow cytometry, microbiology, cytogenetics, molecular studies, tissue bank and electron microscopy. In some instances only a small amount of tissue may be submitted. In such cases, specimen triage is critical and discussion with the reporting Pathologist is advisable to optimise the diagnostic yield of the tissue available. 1,2

Electron microscopy is commonly required for pituitary specimens.1

Transfer majority of specimen to formalin and allow to fix for adequate period.

Intraoperative consultation
  • Not performed
  • Performed, describe type and result
    • Frozen section
    • Imprints
    • Other, describe

If a frozen section is requested the entire specimen must not be submitted (unless further tissue will be sent) for frozen section as freezing introduces significant artefact that may compromise diagnosis.

Follow best practice procedures to minimise cross-over contamination of small fragments to other specimens. 3

See general information for more detail on specimen handling procedures.

Inspect the specimen and dictate a macroscopic description.

External InspectionBack to top


Describe the following features of the specimen:

Procedure

Record as stated by the clinican

Options
  • Biopsy
    • Stereostatic/core
    • Open
OR
  • Dural biopsy –(rare for pachymeningitis or vasculitis)
  • Ultrasonic aspiration –fragments of tissue
  • Subdural and subarachnoid haematoma excision
  • Core biopsy
  • Open biopsy
  • Hypophysectomy
  • Other, describe

Specimen integrity

  • Intact
  • Disrupted/fragmented

Specimen dimensions (mm)

  • Intact specimens in three dimensions 1,4
  • Fragmented specimens; aggregate in three dimensions 1

Photograph the intact specimen, if required.

DissectionBack to top


Specimens containing bone or large areas of calcification may require decalcification (after suficient fixation) prior to dissection and processing. 1,4

Brain biopsies

Small biopsies (<5mm) should not require dissection. Larger biopsies (>5mm in maximum dimension) should be transversely sectioned at 4-5 mm intervals to facilitate fixation.

Pituitary

Dissect a 1-2mm segment for electron microscopy (transfer to 4% glutaraldehyde). Submit remainder of specimen in its entirety. Larger specimens may be sectioned transversely at 3-4mm intervals.

After opening the specimen may require longer fixation in larger quantity of formalin.

Internal InspectionBack to top


Small specimens do not require further description.

Larger specimens, describe the cut surface appearance including the following items:

Specimen description 4

  • Colour
  • Consistency
  • Haemorrhage
  • Necrosis
  • Cystic change
  • Calcification

Photograph the dissected specimen, if required.

Note photographs taken, diagrams recorded and markings used for identification.

ProcessingBack to top


Small biopsies

Transfer whole into appropriately lined cassettes to prevent loss of tissue during processing. The use of sponges should be avoided due to artefactual effects on the specimen.1 Other cassette linings such as lens or filter paper may be more appropriate.

Pituitary
  • Submit all tissue.
Larger brain biopsy specimens
  • Submit all sections in sequential order.

Unprocessed tissue

  • If entire specimen is not processed, record amount of unprocessed tissue remaining (% or g) 7

Record details of each cassette.

An illustrated block key similar to the one provided may be useful.

Small biopsies
Cassette id
Site
No. of pieces
A
Brain biopsy  
Pituitary and larger brain biopsy specimens
Cassette id
Site
No. of pieces
A
Brain/pituitary  

Acknowledgements

Dr Barbara Koszyca for her contribution in reviewing and editing this protocol.

ReferencesBack to top


  1. Wharton SB, Hilton D, Ironside JW, Grant R and Collins VP. Dataset for tumours of the central nervous system, including the pituitary gland, The Royal College of Pathologists, London, 2011.
  2. Timperley WR. ACP Best Practice No 158. Neuropathology. J Clin Pathol 2000;53(4):255-265.
  3. Lester SC. Extraneous Tissue. In: Manual of Surgical Pathology, Saunders Elsevier, Philadelphia, 2010;33-34
  4. Rodriguez M, Hovey E, Jeffree R, Koh E-S, Koszyca B, McKelvie P, McLean C, Robbins P and Robertson T. Central nervous system tumours structured reporting protocol, The Royal College of Pathologists of Australasia, Surry Hills, NSW, 2012.