When cancer is suspected, pathologists examine tissue samples under a microscope. These specialists look for features that indicate the presence of cancer and its potential behavior. Such observations help classify the tumor and guide treatment decisions. One feature pathologists assess is nuclear pleomorphism.
What is Nuclear Pleomorphism?
Nuclear pleomorphism refers to the variability in the size, shape, and staining characteristics of the nucleus within cells, particularly cancer cells. The nucleus serves as the cell’s control center, containing its genetic material. In normal cells, nuclei are uniform and consistent in appearance.
Pathologists note specific irregularities, including variations in nuclear diameter, the presence and size of nucleoli (small structures within the nucleus), and the distribution of chromatin. This is a visual assessment of how abnormal and diverse cell nuclei appear compared to healthy cells.
Defining Nuclear Pleomorphism Score 2
Nuclear pleomorphism is assessed on a scale from 1 to 3, with higher scores indicating greater abnormality. A “Score 2” indicates moderate variability in the appearance of cell nuclei.
Cells with a nuclear pleomorphism score of 2 generally exhibit medium to large nuclei, showing moderate variation in size, shape, and staining intensity. Nucleoli may be noticeable, but the nuclei remain relatively consistent, without highly irregular outlines or unusually large nucleoli. This score distinguishes them from Score 1 (minimal variation, similar to normal cells) and Score 3 (marked variation, including large, irregularly shaped nuclei and coarse chromatin clumping).
How Nuclear Pleomorphism Fits into Cancer Grading
Nuclear pleomorphism is one component of a broader system used to grade cancer, providing an overall assessment of tumor aggressiveness. For breast cancer, it is part of the Nottingham Histologic Grade, also known as the Elston-Ellis modification of the Scarff-Bloom-Richardson system. This widely used system evaluates three distinct features of the tumor cells.
The Nottingham grade also considers tubule formation, which assesses how well tumor cells organize into gland-like structures, and mitotic count, which measures how many cells are actively dividing. Each of these three features is assigned a score from 1 to 3. These individual scores are then added to determine an overall grade for the tumor, typically classified as Grade 1 (scores 3-5), Grade 2 (scores 6-7), or Grade 3 (scores 8-9).
What a Nuclear Pleomorphism Score Means for Patients
The nuclear pleomorphism score, as part of the overall cancer grade, holds significance for a patient’s prognosis and treatment planning. A higher overall cancer grade, which can be influenced by a higher nuclear pleomorphism score, suggests a more aggressive tumor. This may indicate an increased likelihood of the cancer recurring or spreading.
This information helps guide medical decisions regarding treatment, potentially influencing recommendations for therapies such as chemotherapy, radiation, or other targeted treatments. However, the nuclear pleomorphism score is just one piece of the diagnostic puzzle. Doctors consider numerous other factors for a comprehensive assessment and to develop a personalized treatment plan, including tumor size, lymph node involvement, and the tumor’s hormone receptor and HER2 status.