Educational content only. This article is not medical advice, a diagnosis, or a treatment recommendation. It does not create a physician-patient or provider-patient relationship. Clinical decisions should be made with your treating physician.
Before You Read

This guide is for educational purposes only. It is not a substitute for consultation with your treating physician. Every pathology report reflects a unique clinical situation — understanding the terminology is the first step, but your physician is the right person to discuss what your specific findings mean for your care.

Receiving a pathology report can feel overwhelming. The language is technical, the formatting is unfamiliar, and the stakes feel high. Most patients receive their report through a patient portal with no explanation attached — and their physician may have only a few minutes to discuss it at the next appointment.

Understanding the structure of your report will not change what it says. But it can change how you engage with it — and how prepared you are for the conversation with your physician.

The Basic Structure of a Pathology Report

Most surgical pathology reports follow a consistent structure. Once you recognize the sections, the report becomes considerably less intimidating.

Patient and Specimen Identification

At the top of every report you will find identifying information: your name, date of birth, medical record number, the date the specimen was collected, and the laboratory accession number. The accession number is the laboratory's unique identifier for your specimen — it is used to track the tissue from receipt through processing and final diagnosis. If you have questions about a specific report, this number is what the laboratory will use to locate your case.

Clinical History

This section contains the information provided to the pathologist by your physician — typically a brief description of your symptoms, the reason for the procedure, and any relevant medical history. The pathologist uses this context when interpreting your findings. If the clinical history section in your report is incomplete or inaccurate, it is worth noting — the pathologist's interpretation is always made in the context of the information they were given.

Specimen Description

This describes what was submitted to the laboratory. You will typically see the specimen labeled by site — for example, "right breast core biopsy" or "sigmoid colon, resection." If multiple specimens were submitted at the same time — from different sites, or from different procedures — each will be listed separately, usually labeled A, B, C, and so on. Each labeled specimen has its own diagnosis.

Gross Description

The gross description is the Pathologists' Assistant's or pathologist's written record of what the specimen looked like with the naked eye — before any microscopic examination. It documents the size, color, texture, and any visible lesions, along with how the specimen was processed (how it was cut, how many sections were taken, how it was submitted to the laboratory processor).

Most patients skip the gross description, but it contains important information: the size of any lesion, the condition of the surgical margins, and exactly what was sampled for microscopic evaluation. If you see a phrase like "representative sections submitted" — that simply means the pathologist examined representative samples of the tissue, which is standard practice for most specimens.

Microscopic Description

This section describes what the pathologist observed when examining the tissue under a microscope. It is often the most technically dense section of the report, filled with terms that describe cell appearance, tissue architecture, and specific histologic features. Not all reports include a separate microscopic description — some pathologists go directly from the gross description to the diagnosis.

Diagnosis

This is the most important section of the report. The diagnosis line states the pathologist's final conclusion about your tissue. For each labeled specimen, there is a diagnosis. The diagnosis may be:

Important

The diagnosis in your pathology report is the pathologist's interpretation of your tissue under the microscope. It is the most authoritative description of what was found in that specimen. What it means for your treatment, prognosis, and follow-up care is a clinical question — one for your physician, not your pathology report.

Terms You Will Commonly See

Margins
The edges of a surgically removed specimen. "Negative margins" or "clear margins" means tumor was not seen at the edges examined — often considered favorable. "Positive margins" means tumor cells extend to or very close to the edge of the removed tissue.
Grade
The pathologist's assessment of how abnormal the tumor cells appear under the microscope, and how aggressively they appear to be growing. Grade is typically expressed as low, intermediate, or high — or as a number on a scale. Higher grade generally indicates more aggressive behavior, but grade is always interpreted alongside other findings.
Differentiation
Related to grade — how much the tumor cells resemble normal cells. Well-differentiated cells look more like normal cells and tend to grow more slowly. Poorly differentiated cells look very abnormal and tend to grow more quickly.
Invasion
Whether tumor cells have grown beyond their site of origin into surrounding tissue. "In situ" means the tumor is confined to its original location. "Invasive" means it has grown into adjacent tissue.
LVI
Lymphovascular invasion — whether tumor cells are seen inside small blood vessels or lymphatic channels in the specimen. Its presence or absence is one factor your physician will consider.
pTNM
Pathologic staging based on tumor size (T), lymph node involvement (N), and whether cancer has spread to distant sites (M). The lowercase "p" indicates this staging is based on pathologic examination rather than imaging alone.
Mitotic rate
How many cells are actively dividing in a defined area under the microscope. A higher mitotic rate indicates more rapidly dividing cells and is one factor used in grading.
IHC
Immunohistochemistry — a special laboratory test using antibodies to detect specific proteins in the tissue. Used to confirm or refine a diagnosis, determine tumor type, and identify targets for specific treatments.

Addenda and Amended Reports

Sometimes a pathology report is followed by an addendum — an additional report that supplements or amends the original. Addenda are issued when additional testing results become available (such as IHC or molecular testing ordered after the initial diagnosis), when a second opinion is obtained, or when a transcription or administrative error requires correction. If you see an addendum on your report, read both the original and the addendum — the addendum may contain findings that affect the diagnosis.

What to Do With Your Report

Understanding the structure of your report is a starting point, not an endpoint. The terminology guide above can help you decode specific words, but interpreting what your findings mean in your specific clinical context — what they mean for your treatment, prognosis, and next steps — requires a conversation with your treating physician.

When you meet with your physician, consider bringing a written list of the terms you did not understand and the specific questions you want answered. Your physician has the full clinical picture — your imaging, your symptoms, your medical history — and can place your pathology findings in the context that matters most.

Sentinel Clarity Report

If you would like a structured, plain-language expert translation of your specific pathology report — built around the questions you actually have — the Sentinel Clarity Report (SCR) is designed for exactly that. Every SCR is written by a credentialed Pathologists' Assistant with 28 years of surgical pathology experience, delivered securely, and built around your questions.

RW
Robert Weir, PA(ASCP)
Board-certified Pathologists' Assistant (PA(ASCP)) and founder of Sentinel Pathology Consulting, LLC. Robert brings 28 years of quaternary surgical pathology experience, 15 years as laboratory operations manager at two private surgical pathology laboratories, and a current academic role teaching gross surgical pathology to pathology residents.
Last updated: May 2026
Related Patient Resources
How to Read Your Pathology Report → What Is Immunohistochemistry (IHC)? → Understanding pTNM Staging → Request a Sentinel Clarity Report →