Cytologic dysplasia refers to the presence of abnormal cells within a tissue or organ. It signifies disordered cell growth or development, deviating from the typical appearance and arrangement of healthy cells. While the term “dysplasia” might sound concerning, it is not cancer itself, but rather a change that can be a precursor to cancer.
Understanding Cellular Changes
At a microscopic level, dysplastic cells display distinct features compared to normal cells. Normal cells exhibit uniformity in size, shape, and nuclear appearance, with an organized arrangement within their tissue. In contrast, dysplastic cells show variations in size and shape. Their nuclei often appear larger and may have irregular shapes or abnormal mitotic figures, indicating increased cellular proliferation.
The architectural arrangement of cells within the tissue also becomes disorganized in dysplasia, losing their usual polarity. This disruption of normal tissue structure is a hallmark of dysplastic change. Cells become dysplastic primarily due to genetic alterations, such as mutations in genes that regulate cell growth, differentiation, and DNA repair. Environmental factors like exposure to carcinogens (e.g., tobacco smoke), chronic irritation, or infections (e.g., human papillomavirus or HPV) can also contribute to these cellular abnormalities.
Detecting Dysplasia
Detecting cytologic dysplasia begins with routine screening tests. For example, a Papanicolaou (Pap) smear is a widely used screening method for cervical dysplasia, where a healthcare provider collects cervical cells for microscopic examination. While a Pap smear can indicate the presence of abnormal cells, it does not provide a definitive diagnosis. Abnormal Pap test results often lead to further diagnostic procedures.
A colposcopy is performed after an abnormal Pap smear, allowing a magnified view of the cervix, vagina, or vulva. During this procedure, a vinegar solution may be applied to highlight abnormal areas, which appear as whitish patches. If suspicious areas are identified, a biopsy is then performed to collect a small tissue sample for detailed examination by a pathologist. Cytological examinations, such as urine cytology for the urinary tract or sputum cytology for the respiratory tract, also involve analyzing individual cells to detect abnormalities.
Interpreting Results and Risk
The interpretation of dysplastic findings involves a grading system that reflects the degree of cellular abnormality. For cervical dysplasia, the term Cervical Intraepithelial Neoplasia (CIN) is commonly used, classified as CIN 1 (mild), CIN 2 (moderate), or CIN 3 (severe). CIN 1 indicates abnormal cells affecting approximately one-third of the tissue thickness, while CIN 2 involves one-third to two-thirds, and CIN 3 affects more than two-thirds of the epithelium. Another classification, Squamous Intraepithelial Lesion (SIL), categorizes dysplasia as low-grade SIL (LSIL) or high-grade SIL (HSIL, including CIN 2 and CIN 3).
Dysplasia is not cancer, but it represents a spectrum of risk for progression to cancer. Mild dysplasia (CIN 1 or LSIL) frequently resolves on its own without intervention, with only about 1% progressing to cervical cancer. High-grade lesions (CIN 2/3) can also regress spontaneously in 6% to 50% of cases, depending on factors like HPV type. Factors influencing the risk of progression include the grade of dysplasia, the specific body site affected, and persistent infection with certain high-risk human papillomavirus (HPV) types.
Next Steps After Diagnosis
Following a diagnosis of cytologic dysplasia, the management approach varies depending on the grade of dysplasia and the affected body site. For mild cases, such as CIN 1, healthcare providers recommend watchful waiting and regular monitoring through follow-up Pap tests. This allows time for the body to potentially clear the abnormal cells naturally, as many low-grade dysplasias resolve spontaneously. Adherence to scheduled follow-up appointments is important to track any changes.
When dysplasia is more severe (e.g., CIN 2 or CIN 3) or persists, intervention may be recommended to remove or destroy the abnormal cells. Common procedures for cervical dysplasia include Loop Electrosurgical Excision Procedure (LEEP), where an electrically charged wire loop removes affected tissue. Other options include cryotherapy, which freezes abnormal cells, or cold knife conization, involving surgical removal of a cone-shaped tissue section. These treatments aim to prevent progression to invasive cancer and are effective in a high percentage of cases, around 90% for CIN 2 and 3.