  |
|
Surgical-Pathology.com
|
Invasive esophageal squamous cell carcinoma evolves through a series of preinvasive lesions, known as dysplasias or intraepithelial neoplasias.
Esophagus has its own unique types which may differ from those occurring in other squamous sites, such as cervix and skin.
According to some studies these precursor lesions were more common in high cancer-risk areas than in the low-risk areas. There is an increased proliferation of cells in the upper layers of the esophageal squamous epithelium in people who live in these areas.
Although lower grades of dysplasia are usually described as partial-thickness abnormalities, involving less than half of the epithelial thickness and higher grades as involving more than half, separating grades of dysplasia on the basis of level of involvement is not always reliable. Also, separating one grade of dysplasia from another is frequently difficult, since there are no clear lines of demarcation. As a result, even with a two-grade system that includes low and high grades, there are occasional dysplasias that seem to be borderline or intermediate between the two grades. In the future, all intraepithelial proliferations might be grouped into a spectrum that could be designated esophageal intraepithelial neoplasia (EIN), comparable to the terms in use for the uterine cervix, the vagina, and the vulva, or into a two-grade dysplasia system comparable to that used in ulcerative colitis.
The lesion is visible endoscopically and is confirmed histologically
Microscopic features : The preinvasive lesions, or dysplasias, contain abnormal epithelia which vary from that closely resembling the normal squamous mucosa to epithelium so disorganized that its malignant cytologic and architectural features are obvious.
There are atypical squamous cells with disorganized architecture and abnormal differentiation within the epithelium. These features are obvious in high grade dysplasia. The nuclei are larger and more hyperchromatic than normal, and there is increased mitotic activity . The lower grades of dysplasia have a larger component of mature-appearing squamous cells, some of which may be keratinized, and the abnormal cells are often limited to the lower half of the epithelium .
The highest grade of dysplasia is squamous cell carcinoma in situ or intraepithelial carcinoma.
.
The histological variants:
1.Basal squamous dysplasia 2.Pagetoid squamous dysplasia
The lesion may present as a single lesion in the absence of invasive tumour or as a peripheral component in the backround squamous mucosa , with invasive squamous carcinoma.