Understanding Your Pathology Report: Lung Cancer In Situ, Hyperplasia, Metaplasia, Dysplasia

If you have recently been diagnosed with lung cancer, you may have many questions for your doctor. Everything might seem confusing and overwhelming. Through this process, your doctor will likely have provided you with a pathology report containing the details of your diagnosis. However, this report may be difficult to comprehend as it is filled with medical jargon and terminologies. To better understand your pathology report, this article will elaborate on several common terms frequently used in pathology reports. By familiarizing yourself with these terms, you can better comprehend your diagnosis and make informed decisions.

The in situ disease, or stage 0 disease, refers to precancerous cells that grow at the “original place” (in situ) and have not spread to nearby lung tissue. Although it is considered a pre-cancer stage, carcinoma in situ appears abnormal under the microscope compared to normal, healthy cells.

Related: What Is Stage 0 Lung Cancer?

These terms are used to classify lung adenocarcinoma multistep progression, from pre-cancer to invasive stage. These stages are classified based on complex histopathologic features (microscopic appearances) and lesion size.

Normally, the lining of healthy lungs is made up of rectangular cells that stand next to each other, forming a uniform layer. However, when the lungs are injured or irritated (for example, during an infection or smoking), these cells transform into irregular shapes stacked on top of each other. This change in cell shape is called squamous metaplasia.

It is important to note that squamous metaplasia is not a pre-cancerous condition. When the lining recovers, the cells return to their healthy rectangular shape. However, if the injury of irritation persists and the lining is not able to restore itself, it can progress to dysplasia.

Similar to the multistep progression of lung adenocarcinoma, squamous cell carcinoma develops from a pre-cancer stage - dysplasia. There are three levels of dysplasia – mild, moderate and severe, judging from how severe or abnormal the cells appear under the microscope.

As the severity of dysplasia increases, it appears more similar to squamous cell carcinoma in situ.

These are non-cancerous (benign) changes in cell appearances seen under the microscope. They may be found in the biopsy sample containing pre-cancer or invasive carcinoma.

A granuloma is a small area containing immune cells triggered during an inflammation (caused by toxic substances) or an infection (by germs). The pathologist may apply germ-staining dye to the biopsy slides to check for infection.

The injury from inflammation or infection may form thickened, stiff tissue that appears like a scar under the microscope.

Learn more about lung biopsy here.

If the disease has been identified as in situ, it is considered a strong risk factor or predictor of progression to invasive disease. On the other hand, hyperplasia and dysplasia without invasive carcinoma typically have excellent prognosis and are almost curable. Otherwise, there may be other areas in the lungs with pre-cancer lesions or even invasive carcinoma that was not biopsied.

Familiarizing yourself with the different terms associated with lung cancer can be very helpful. This article exemplifies how each term differs and whether they may be a cause of concern. Expecting the worst or believing each result has dire consequences is normal. Take comfort in having viable treatment plans and points of action during your cancer journey. Trust in the knowledge and expertise of your healthcare team to help you regain your health and well-being.

Related: Non-Small Cell Lung Cancer

Related: Your Guide To Lung Cancer Pathology Report