01Purpose and principlesWhat the assessment is for and the core concepts behind it.
Biopsy converts a clinical or radiological suspicion into a tissue diagnosis. The safest method balances diagnostic yield against bleeding, seeding, organ injury, anaesthetic burden and preservation of curative options. A superficially accessible metastasis may be preferable to a hazardous primary, while some lesions need excision intact or specialist biopsy-track planning. The responsible multidisciplinary team should determine the route when sarcoma, adrenal, testicular, ovarian, central nervous system or other pathway-sensitive tumours are possible.
Pathology proceeds from specimen identity and adequacy to morphology, immunophenotype and selected genomic or other biomarker testing. Grade, invasion, margins, lymphovascular spread and response to neoadjuvant therapy may be required depending on specimen. Molecular analysis has distinct diagnostic, predictive and inherited-risk roles. The report must state limitations, particularly after low cellularity, crush artefact, fixation delay or bone decalcification.
Discordance is a clinical finding. A benign or non-diagnostic sample does not safely overrule progressive imaging, and unexpected aggressive histology should prompt identity and radiology review. The next step may be deeper sections, additional staining, re-biopsy, a different lesion or definitive excision. Decisions belong in a multidisciplinary forum with radiology and pathology present.
Key points
- Obtain tissue only when the result will change diagnosis or management and the route does not compromise later surgery, staging or safety.
- The preferred biopsy is lesion- and pathway-specific: cytology, core biopsy, endoscopic sampling, marrow sampling or excision answer different questions.
- Exclude procedure-specific hazards such as phaeochromocytoma, coagulopathy, vascular lesion and unsafe anatomical access before sampling.
- Histological morphology and immunohistochemistry establish lineage; molecular tests refine classification, prognosis or treatment selection rather than replacing tissue context.
- Plan fixation, transport and allocation before the procedure because decalcification, scant cells or exhausted blocks can prevent essential biomarkers.
- A negative biopsy can mean no cancer, sampling error, necrosis or an unsuitable assay; radiology-pathology discordance requires review.
- Do not request broad molecular panels without a defined decision, validated platform and plan for uncertain or possible germline findings.
- Communicate the final integrated diagnosis, uncertainty, specimen adequacy and pending addenda to the treating multidisciplinary team.
02Indications, selection and cautionsWhen it is useful, when urgency changes and important limitations.
An accessible viable lesion with adequate solid tissue and low procedural risk is usually preferable to necrotic or technically hazardous disease.
A suspected sarcoma, phaeochromocytoma or other tumour can be harmed by unplanned biopsy, requiring specialist discussion before needle placement.
Scant tumour, crush, necrosis, poor fixation or decalcification may prevent diagnosis and biomarkers despite a technically completed procedure.
Benign histology that does not explain suspicious imaging, growth or examination should trigger combined pathology-radiology review.
Tumour phenotype or molecular result may raise constitutional risk but requires consented germline confirmation before family action.
03Method and interpretationA systematic approach to the test and its findings.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Image-guided core biopsyFirst step - Why
- Obtain architecture and material for immunohistochemistry and molecular testing.
- Interpretation and limitations
- Target viable enhancing tissue, plan a resectable track where relevant and balance core number against bleeding or organ risk.
- 02
Fine-needle aspiration cytology - Why
- Assess cells in selected thyroid, nodal or fluid lesions.
- Interpretation and limitations
- Cytology may be sufficient in defined pathways but often cannot show invasion or full architecture; a non-diagnostic aspirate needs planned escalation.
- 03
Histology and immunohistochemistry - Why
- Determine lineage, subtype, grade and relevant protein expression.
- Interpretation and limitations
- Interpret a panel rather than one stain, using internal controls and clinical-radiological context; poorly differentiated tumours may remain uncertain.
- 04
Predictive molecular or protein biomarker - Why
- Identify a validated treatment-selection marker.
- Interpretation and limitations
- Test the correct specimen at the correct disease stage and report assay, threshold framework and limitations; uncertain variants are not actionable.
- 05
Germline confirmation - Why
- Establish whether a tumour clue represents inherited predisposition.
- Interpretation and limitations
- Use a non-tumour sample through genetics with consent; somatic findings alone cannot define relatives' risk.
04Clinical next stepsHow the result changes management or prompts escalation.
01PlanChoose the specimen and routeFirst stepImaging suggests malignancy and tissue confirmation will change care.+
- 1Review differential, staging imaging, accessible lesions, coagulation, medicines and tumour-specific hazards with the responsible team.
- 2DefinitiveSelect the least harmful route that provides enough tissue for morphology and mandatory biomarkers without compromising definitive surgery.
- 3Pre-alert pathology about suspected diagnosis, fresh-tissue or molecular requirements, infection risk and specimen transport.
02ReportBuild an integrated diagnosisThe laboratory receives a correctly identified sample.+
- 1Assess adequacy and morphology first, then use a focused immunohistochemical panel to establish or narrow lineage.
- 2Add validated molecular or predictive assays only where the result contributes to classification, prognosis, inherited risk or treatment selection.
- 3Issue a structured report with specimen type, diagnosis, grade or stage elements, biomarker method, limitations and pending addenda.
03ResolveManage an inadequate or discordant biopsyTissue is non-diagnostic or inconsistent with the clinical and radiological picture.+
- 1Confirm specimen identity and review slides with imaging to distinguish true benign tissue from sampling error or tumour heterogeneity.
- 2AlternativeDecide whether deeper sections, another assay, repeat core, alternative lesion or excision will answer the unresolved decision.
- 3DefinitiveContinue appropriate clinical surveillance or treatment of immediate complications while obtaining definitive evidence; do not let non-diagnostic mean discharged.
05Risks, monitoring and follow-upComplications, safety checks and further assessment.
- Observe the procedure-specific period for bleeding, pneumothorax, pain, infection, organ injury or sedation effects and give explicit return triggers.
- Track the specimen from collection to accession and record whether fresh, fixed, cytogenetic or microbiology material was required.
- Confirm final report and all molecular addenda reach the MDT; preliminary verbal impressions must not become the permanent diagnosis.
- Audit tissue adequacy, repeat-biopsy rates, complications and biomarker failure by procedure and site.
- Preserve remaining material and document exhaustion so future treatment teams know whether repeat tissue is needed.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Biopsy is an intervention
Its route can seed a compartment, cause haemorrhage or remove tissue needed later, so planning matters as much as needle accuracy.
Architecture changes meaning
Cytology may identify malignant cells but cannot always demonstrate invasion, grade or spatial pattern needed for classification.
More testing uses tissue
Large panels can exhaust a small block and delay the few validated markers that determine current treatment.
Discordance needs a meeting
Pathology, radiology and clinical teams often resolve apparent contradiction by identifying sampling, labelling or disease-heterogeneity problems.
Tumour is not germline
A pathogenic variant in cancer tissue can be acquired; relatives need a confirmed constitutional result before predictive testing.
07Common pitfallsFrequent interpretation and management errors.
- 01
Biopsying before checking tumour-specific hazards.
- 02
Choosing a necrotic target because it is largest.
- 03
Failing to plan a biopsy track for later excision.
- 04
Exhausting scant tissue on low-value tests.
- 05
Treating non-diagnostic tissue as benign.
- 06
Acting on a molecular result without tumour context.
- 07
Losing ownership of pending addenda.