In pathology, a tangentially sectioned tissue sample is one cut at an angle rather than straight across. When a sample is cut at an angle, the layers of tissue overlap in the thin slice placed on the microscope slide. This can make the sample difficult to interpret, and sometimes it prevents the pathologist from seeing important structures clearly.
Tangential sectioning is most commonly used for small tissue samples, such as biopsies.
Before a pathologist can examine tissue under the microscope, the specimen must be processed and cut into extremely thin slices. This cutting is performed by a trained laboratory professional using a microtome.
Tangential sectioning can occur for several reasons:
The tissue may be irregularly shaped or flattened during surgery, making it difficult to position correctly.
The specimen may be placed into the microtome at an angle, causing the blade to pass through different levels of the tissue in a single cut.
Very small or soft pieces of tissue can be harder to orient properly, increasing the chance of angled cuts.
When tissue is cut tangentially, the resulting slide combines several layers into a single thin section, which can blur or distort important features.
A tangentially sectioned sample can make it harder for the pathologist to provide a clear or complete diagnosis. Important findings—such as the actual thickness of a lesion, the appearance of specific cells, or whether a tumor reaches a margin—may be difficult or impossible to evaluate when the tissue is angled.
If the pathologist cannot confidently interpret the sample due to tangential sectioning, they may recommend:
Cutting additional deeper levels of the same tissue block
Repeating the biopsy to obtain more tissue
Reorienting and recutting the specimen if possible
This ensures you receive an accurate diagnosis from the highest-quality tissue sections.
Was my biopsy affected by tangential sectioning?
Do I need a repeat biopsy or additional testing?
Could tangential sectioning have affected my diagnosis or treatment plan?
Will more tissue be reviewed to clarify the results?