When a biopsy result is wrong: can a histopathology error give rise to a medical negligence claim in NSW?

That sentence — or something very close to it — is one of the most devastating things a person can hear in a medical context. The tissue was there. The answer was there. Someone looked at it and reached the wrong conclusion, or reached the right conclusion and told no one, or told the wrong person, or filed the result and moved on. By the time the truth emerged, the disease had progressed. Treatment that would have been straightforward became aggressive. Outcomes that were once excellent became uncertain.

This article explains what histopathology errors are, what the standard of care requires of pathologists and the clinicians who rely on their reports, where that standard breaks down, and what the law in NSW says about the harm that follows.

What histopathology is and how it fits into clinical care

Histopathology is the microscopic examination of tissue — typically a biopsy specimen — to identify disease. A pathologist receives a tissue sample, processes it into thin sections, stains those sections, and examines them under a microscope to determine whether abnormal cells are present, what type they are, and how aggressive they appear. The pathologist then produces a written report that the treating clinician uses to make diagnostic and treatment decisions.

Biopsy and histopathological analysis underpin the diagnosis of cancer, inflammatory bowel disease, skin conditions, lymphoma, cervical abnormalities, and dozens of other serious conditions. For many of these conditions, the histopathology report is not one piece of evidence among many — it is the definitive diagnostic step. Everything that follows depends on it being right.

According to the Healthdirect Australia health information service, biopsy is the standard method for confirming a cancer diagnosis, and the accuracy of that diagnosis directly determines the treatment pathway a patient enters.¹ A false negative — a report that says no cancer is present when cancer is in fact present — sends a patient away from treatment they need. A false positive — a report that says cancer is present when it is not — sends a patient into treatment they do not need, with all the physical and psychological consequences that entails.

The histopathology process involves multiple steps and multiple people. A surgeon or proceduralist collects the specimen. A nurse or technician labels and packages it. A courier or internal transport system moves it to the laboratory. A laboratory scientist processes and prepares the slides. A pathologist examines those slides and writes the report. A medical secretary or electronic system transmits the report to the requesting clinician. That clinician reads it, interprets it, and communicates the result to the patient. Each of those steps is a point at which error can enter the chain.

The standard of care — what pathologists and treating clinicians are required to do

The “standard of care” in law means the standard of reasonable care that a person with the relevant professional skill and knowledge would exercise in the same circumstances. For a pathologist, that standard is defined by what a reasonably competent pathologist, exercising ordinary professional skill, would do when examining a particular specimen. It is not the standard of the best pathologist in the country. It is the standard of a competent one.

That standard has several specific components in the histopathology context.

What the pathologist is required to do

A competent pathologist must examine the specimen systematically and thoroughly. They must correlate the microscopic findings with the clinical information provided on the request form — a pathologist who ignores the clinical context and reads slides in isolation is not meeting the standard. They must apply current diagnostic criteria for the tissue type and suspected condition. Where findings are ambiguous or at the borderline of a diagnostic category, a competent pathologist must either seek a second opinion from a colleague, request additional staining or molecular testing, or clearly flag the uncertainty in the report.

The report itself must be accurate, complete, and unambiguous. Where a pathologist uses qualifying language — “consistent with,” “cannot exclude,” “suggestive of” — the treating clinician must be able to understand what action that language requires. A report that buries a significant finding in qualified language, without making clear that further investigation is warranted, does not meet the standard.

What the treating clinician is required to do

The duty does not end with the pathologist. The clinician who requested the biopsy — whether a GP, surgeon, gastroenterologist, or dermatologist — carries an independent duty to receive the report, read it, understand it, and act on it appropriately. A clinician who requests a biopsy and then fails to follow up the result has breached their duty of care, regardless of what the pathologist’s report said.

Equally, a clinician who receives a report that flags uncertainty or recommends further investigation, and takes no action on that recommendation, has failed the patient at a separate and independent point in the chain.

The infographic below maps the four critical decision points in the histopathology chain and the specific failure mode at each.

Where care breaks down — specific failure patterns in histopathology

Histopathology errors do not follow a single pattern. They occur at different points in the chain, for different reasons, and with different legal consequences. Understanding the specific failure mode matters — because the identity of the responsible party, and the nature of the breach, depends on exactly where in the chain the error occurred.

The false negative: cancer present, report says benign

A false negative is the most consequential histopathology error. The pathologist examines the slides and concludes that no malignancy is present. The report says “benign” or “no evidence of malignancy.” The treating clinician reads that report and reassures the patient. The patient goes home.

She went home. She was told the lump was nothing to worry about. Eighteen months later, she returned with a mass that had spread to her lymph nodes. When the original slides were reviewed, the malignant cells were visible. They had been there all along.

False negatives occur for several reasons. Sampling error — where the biopsy needle missed the abnormal tissue — is one cause, and it may not constitute negligence if the sampling technique was appropriate. But interpretive error — where the pathologist examined slides that contained abnormal cells and failed to identify them — is a different matter entirely. That failure is measured against what a competent pathologist, examining those same slides, would have seen.

Cognitive factors drive many interpretive errors. Anchoring bias — where the pathologist is influenced by a clinical history that suggests a benign condition — can cause them to interpret borderline findings in a benign direction. Fatigue and high workload, both well-documented features of Australian pathology practice, increase the rate of interpretive error. Neither factor excuses the error. Both explain why it happens.

The false positive: benign tissue, report says malignant

A false positive sends a patient into treatment they do not need. A woman told she has cervical cancer in situ undergoes a cone biopsy — a surgical procedure with real physical consequences — when the tissue was in fact normal. A man told he has prostate cancer undergoes radical prostatectomy, with permanent effects on continence and sexual function, when a second pathologist reviewing the same slides would have graded the tissue as benign.

False positives are less common than false negatives, but their consequences are not less serious. The harm is different — it is the harm of unnecessary treatment rather than delayed treatment — but it is real, measurable, and legally cognisable.

The specimen mix-up: the wrong patient’s tissue examined

Specimen mix-up — where one patient’s tissue is processed or reported under another patient’s identifying information — is a laboratory error rather than an interpretive one. The pathologist may read the slides correctly. The error lies in the chain of custody: the specimen was mislabelled at collection, or switched during processing, or reported under the wrong patient’s name.

The consequences are bilateral. Patient A receives a false negative because their tissue was reported as Patient B’s benign specimen. Patient B receives a false positive because their benign tissue was reported as Patient A’s malignant specimen. Both patients are harmed. The laboratory’s systems — not any individual pathologist’s interpretive skill — are the source of the failure.

This type of error engages the institutional duty of care owed by the laboratory and the health service. The Australian Commission on Safety and Quality in Health Care has identified specimen labelling and patient identification as a persistent source of preventable harm in Australian health services, and its National Safety and Quality Health Service Standards impose specific requirements on laboratories to prevent exactly this type of error.²

The failure to act on a significant result

Sometimes the pathologist does everything right. The report is accurate, complete, and clearly flags a significant finding. The report is transmitted to the requesting clinician. And then nothing happens.

The clinician does not read the report. Or reads it and misunderstands it. Or reads it, understands it, and intends to follow up — but the follow-up never occurs because no system exists to ensure it does. The patient is never told. Months pass. The disease progresses.

This failure pattern is not a pathology error. It is a clinical governance failure. The duty to act on a pathology result rests with the requesting clinician, and in an institutional setting, with the health service that employs them. A GP who requests a skin biopsy and then fails to chase the result when the patient does not return for follow-up has breached their duty of care. A hospital that has no system for ensuring that critical pathology results reach a responsible clinician has failed at the institutional level.

The failure to recommend or perform a biopsy at all

A distinct failure pattern involves the clinician who should have ordered a biopsy and did not. A dermatologist who examines a lesion with features suspicious for melanoma and decides to “watch and wait” without taking a sample. A gastroenterologist who performs a colonoscopy, identifies a polyp, and does not biopsy it. A GP who sees a patient with persistent symptoms consistent with colorectal cancer and does not refer for investigation.

In these cases, the histopathology error is an error of omission — the tissue was never examined because no one ordered the examination. The failure is in the clinical decision-making that preceded the biopsy, not in the laboratory that processed it.

The legal framework in NSW

Medical negligence claims in NSW are governed by the Civil Liability Act 2002 (NSW). That Act sets out the legal framework within which a patient who has suffered harm from a clinical failure must establish their claim. Three elements must be proved: duty of care, breach of that duty, and causation of harm.

The duty of care in histopathology cases is owed by multiple parties simultaneously. A pathologist owes a duty of care to the patient whose tissue they examine — even though the pathologist typically has no direct clinical relationship with that patient. The duty arises from the fact that the pathologist’s report will foreseeably be relied upon to make decisions about that patient’s health. The requesting clinician owes a separate and independent duty. The laboratory, as an institution, owes a duty in relation to its systems and processes. A hospital that employs pathologists and operates a laboratory owes a non-delegable duty of care to patients whose specimens pass through that laboratory.

Section 5O: the peer professional opinion defence

Section 5O of the Civil Liability Act 2002 (NSW) provides that a clinician does not breach their duty of care if they acted in a manner that was widely accepted by peer professional opinion as competent professional practice. This defence is sometimes called the “Bolam defence” — after the English case that established a similar principle — though Australian law has modified it significantly.

Section 5O does not protect every clinician in every situation. The court retains the power to reject a peer professional opinion if it concludes that the opinion is not reasonable or is not responsible. A body of professional opinion that accepts a practice that carries an obvious and foreseeable risk of harm — and that risk is not outweighed by any countervailing benefit — will not protect a defendant. In histopathology cases, where the standard of care is often defined by specific RCPA guidelines and quality standards, a pathologist who departs from those standards cannot simply point to a colleague who would have done the same thing.

Section 5D: causation

Section 5D requires the plaintiff to establish that the breach was a necessary condition of the harm — the “but for” test. In histopathology cases, this means establishing that but for the error, the patient would have received a correct diagnosis and appropriate treatment, and that the outcome would have been materially better.

Causation is often the most contested element in these cases. A defendant will argue that even with a correct diagnosis, the outcome would have been the same — that the cancer was already at a stage where treatment would not have succeeded. The plaintiff must lead expert evidence establishing that earlier diagnosis would have led to earlier treatment, and that earlier treatment would have produced a materially better outcome. For many cancers, that evidence is available and compelling: survival rates at Stage I are dramatically better than at Stage III or IV, and the difference between those stages is often measured in months of diagnostic delay.

For a comprehensive overview of how these elements operate together in NSW, see Reframe Legal — Medical Negligence.

When a histopathology error may amount to medical negligence

Not every wrong biopsy result is negligence. Some diagnostic errors fall within the range of outcomes that even a competent pathologist, exercising reasonable care, might produce — particularly where the tissue is genuinely ambiguous, the clinical history is limited, or the condition is rare. The legal question is not whether the result was wrong. It is whether the process that produced the wrong result fell below the standard of a reasonably competent pathologist in the same circumstances.

If the pathologist failed to identify findings that were visible on the slides

Where expert review of the original slides reveals that the abnormal cells were present and identifiable, and a competent pathologist examining those slides would have identified them, the interpretive error is likely to constitute a breach. The question is not whether the pathologist tried hard enough. It is whether the result they reached was one that a competent pathologist, applying the standard diagnostic criteria for that tissue type, would have reached.

If the pathologist failed to seek a second opinion on ambiguous findings

Where the slides presented genuinely borderline findings — findings that a competent pathologist would have recognised as requiring collegial review or additional testing — and the pathologist instead made a definitive call without seeking that review, the failure to escalate may itself constitute the breach. The RCPA’s quality standards specifically address the obligation to seek peer review in cases of diagnostic uncertainty.

If the clinician failed to act on a report that required action

Where the pathology report clearly identified a significant finding — or clearly recommended further investigation — and the treating clinician took no action, the breach lies with the clinician rather than the pathologist. The legal analysis focuses on what the report said, what a competent clinician reading that report would have done, and what the clinician actually did.

If the patient was never informed of a significant result

Where a patient was not told the result of their biopsy — whether because the result was lost, the clinician failed to follow up, or no system existed to ensure communication — and the patient suffered harm from the resulting delay, both the individual clinician and the health service may bear liability. This scenario engages not only the standard of care but also the informed consent framework established in Rogers v Whitaker (1992) 175 CLR 479, which requires that patients be given information that is material to their decisions about their own health.³

If a biopsy was not performed when the clinical picture required one

Where a clinician examined a patient, identified features that a competent clinician in that specialty would have recognised as requiring histopathological investigation, and failed to order a biopsy, the failure to investigate is itself the breach. The harm is the delay in diagnosis that resulted from the failure to obtain tissue confirmation at the point when the clinical picture warranted it.

The three elements applied to histopathology errors

For a histopathology error to give rise to a successful negligence claim in NSW, all three elements — duty, breach, and causation — must be established. The presence of an error, even a serious one, does not automatically satisfy all three. What the law requires is that the error fell below the standard of reasonable care, and that the harm the patient suffered was caused by that departure from the standard — not by the underlying disease alone.

Long-term and permanent harm from histopathology errors

The harm produced by a histopathology error is rarely confined to the period of delay. For most serious conditions — and particularly for malignancies — the harm compounds over time in ways that are both medically predictable and legally significant.

Disease progression and treatment escalation

A cancer diagnosed at Stage I typically requires less aggressive treatment than the same cancer diagnosed at Stage III. Early-stage colorectal cancer may be treated with surgical resection alone. The same cancer, diagnosed eighteen months later at Stage III, requires surgery followed by chemotherapy and radiation. The physical burden of that additional treatment — nausea, fatigue, peripheral neuropathy, immune suppression — is itself a form of harm caused by the delay. So is the reduced probability of cure.

For melanoma, the difference between a correct diagnosis at 0.5mm Breslow thickness and a delayed diagnosis at 3mm thickness is the difference between a wide local excision and sentinel lymph node biopsy, immunotherapy, and a five-year survival rate that has fallen from above 95% to below 65%.⁴ That gap — in treatment burden, in prognosis, in life expectancy — is the harm the law is asked to compensate.

Psychological consequences

The psychological harm of a histopathology error is substantial and well-documented. Patients who receive a delayed cancer diagnosis commonly experience post-traumatic stress disorder, major depressive disorder, and severe health anxiety. The experience of having been told “you are fine” and then discovering that the answer was wrong — that the system failed them at the most fundamental level — produces a specific form of distrust in medical institutions that can persist for years and interfere with future healthcare engagement.

Patients who received a false positive diagnosis and underwent unnecessary treatment carry a different but equally serious psychological burden: the knowledge that their body was subjected to surgery, chemotherapy, or radiation that it did not need, and that the harm from that treatment is permanent.

Financial and economic consequences

The financial consequences of a delayed or incorrect diagnosis include the cost of more extensive treatment, lost income during treatment and recovery, the cost of ongoing monitoring and follow-up care, and — in cases of permanent disability — the cost of home modification, assistive equipment, and paid care. For patients who were working at the time of the error and can no longer work at the same capacity, the economic loss can extend across decades.

What compensation covers in NSW

A successful medical negligence claim in NSW can recover two broad categories of damages: general damages (also called non-economic loss) and special damages (economic loss and out-of-pocket expenses).

General damages compensate for pain, suffering, loss of enjoyment of life, and loss of expectation of life. Under section 16 of the Civil Liability Act 2002 (NSW), non-economic loss is only recoverable if the severity of the harm is at least 15% of the most extreme case. This threshold means that minor or temporary harm may not attract general damages — but for patients who have suffered significant disease progression, permanent disability, or a materially reduced life expectancy as a result of a histopathology error, the threshold is typically met.

Special damages cover past and future medical expenses, lost income (past and future), the cost of paid care, and the cost of home modification or assistive equipment. In cases involving a delayed cancer diagnosis, the difference between the treatment the patient received and the treatment they would have received with a timely diagnosis — in cost, in duration, and in physical burden — forms a significant component of the special damages claim.

Under the Limitation Act 1969 (NSW), a claim must ordinarily be commenced within three years of the date on which the cause of action accrues. For histopathology errors, the cause of action typically accrues when the patient discovers — or ought reasonably to have discovered — that they suffered harm as a result of the error. Where the error was concealed by the nature of the condition itself (as is common in delayed diagnosis cases), the limitation period may run from the date of discovery rather than the date of the biopsy.

These figures are general reference ranges only. Each case turns on its own evidence — medical records, expert clinical opinion, and economic reports that quantify the actual loss.

How to think about your own situation

Reading about histopathology errors in the abstract is one thing. Applying that framework to your own experience is harder — particularly when you are still processing what happened, or when the people around you have discouraged you from asking questions.

These questions are not a legal test. But the pattern they reveal — when several of them point in the same direction — is often the starting point for a proper examination of whether the standard of care was met. The question is not whether you feel certain that something went wrong. The question is whether the objective evidence — the slides, the report, the clinical records, and the expert opinion of a competent pathologist reviewing that material — supports the conclusion that the care fell below the required standard.

For a detailed explanation of how a claim of this kind proceeds in NSW, see Reframe Legal — How Medical Negligence Claims Work in NSW.

Uncertainty is normal — and it is not evidence that nothing went wrong

Most people who have experienced a histopathology error spend a long time doubting themselves before they seek any kind of examination of the facts. They were told the result was fine. They trusted the system. When the truth emerged, their first instinct was often to wonder whether they had misunderstood something, or whether they were being unfair to the clinicians involved.

That self-doubt is a rational response to a confusing experience. It is not evidence that nothing went wrong.

The legal analysis of a histopathology error does not depend on how certain the patient feels. It depends on objective evidence: the original slides, the original report, the clinical records, and the opinion of an expert pathologist who reviews that material and assesses whether the original interpretation met the standard of a reasonably competent pathologist. That assessment is made against an objective benchmark — not against the patient’s subjective sense of what happened.

Many people in this situation also feel reluctant to pursue a legal examination because they do not want to cause harm to a clinician who may have been doing their best. That concern is understandable. What the law asks is not whether the clinician intended to cause harm. It asks whether the care they provided met the standard the profession sets for itself. Those are different questions, and the answer to the second does not depend on the answer to the first.

Where a histopathology error also involved a failure to disclose a significant finding to the patient — or a failure to explain the implications of an ambiguous result — the informed consent framework may also be relevant. The law on informed consent in Australia, established in Rogers v Whitaker and developed in subsequent cases, requires that patients be given information that is material to their decisions about their own health. A patient who was not told that their biopsy result was uncertain, or that further investigation was recommended, was denied information they had a legal right to receive. For more on this framework, see Reframe Legal — Informed Consent and Medical Negligence.

Complaints about pathologist conduct can also be made to AHPRA — Australian Health Practitioner Regulation Agency, which regulates medical practitioners including pathologists in Australia. A complaint to AHPRA and a civil negligence claim are separate processes with different purposes — one addresses professional conduct, the other addresses compensation for harm — and pursuing one does not preclude the other.

About Dr Rosemary Listing

Dr Rosemary Listing is a lawyer with a PhD in law, specialising in medical negligence. Her legal practice concentrates on cases where clinical care in NSW failed to meet the standard the law and the profession require. Her doctoral research and legal practice have given her a rigorous command of the clinical standards against which negligent conduct is measured, and of the evidentiary requirements those claims must satisfy in NSW courts.

Histopathology and biopsy error cases occupy a distinctive position in medical negligence law. The failure is often invisible to the patient for months or years — the tissue was examined, a report was produced, and the system appeared to function. The harm only becomes apparent when a second clinician, or a second review of the original slides, reveals that the first answer was wrong. That invisibility makes these cases legally complex: establishing when the cause of action accrued, identifying which party in the chain bears responsibility, and proving that the outcome would have been materially different with a correct diagnosis all require careful analysis of both the clinical and legal evidence.

The cases that have reached NSW courts, and the complaints recorded by the Health Care Complaints Commission, reveal a consistent pattern in how histopathology failures occur and how they are assessed. The most common thread is not a single catastrophic error but a series of smaller failures — an ambiguous report that was not flagged, a result that was not followed up, a recommendation for further investigation that no clinician acted upon — that together produced a delay with serious consequences. Courts and tribunals have consistently held that each party in the histopathology chain carries an independent duty, and that the failure of one does not extinguish the liability of another.

The people who seek a legal examination of their pathology records are not looking to blame anyone. They want to understand what happened — why the result was wrong, who was responsible for acting on it, and whether the harm they now carry was avoidable. Many waited a long time before seeking any kind of examination of the facts, often because they doubted themselves, or because those around them discouraged them from asking questions.

Dr Listing examines medical records alongside expert clinical opinion and applies the legal standard — not to assign blame, but to give people an honest answer about whether what happened to them met the benchmark the profession sets for itself. That answer, whatever it is, is what most people are actually seeking.

This article contains general legal information only. It does not constitute legal advice, and reading it does not create a lawyer–client relationship. The law discussed applies to New South Wales, Australia. Each person’s circumstances differ. Time limits apply to legal claims in NSW, and these limits may affect your position. You should seek independent legal advice about your specific situation.