EPITHELIAL TUMORS
1. BENIGN TUMORS
A / Benign tumors of the epithelial linings
a) Benign tumors of malpighian epithelia
On clinical examination, these are most often exophytic lesions, protruding from the skin or mucous membrane, and are generally referred to as papilloma .
Microscopically, the papilloma is characterized by the association of three characteristics: papillomatosis (the malpighian epithelium forms digitiform folds, centered by a stretched connective tissue axis), hyperacanthosis, i.e. hyperplasia (increase in the number of cells) of the Malpighian mucosa, hyperkeratosis (thickening of the horny layer). The cytological appearance is normal: there is no cytonuclear atypia, no abnormal mitosis and the whole is limited by an intact basement membrane.
Benign tumors of the squamous epithelium of the mucous membranes also meet the general definition of papillomas. A papilloma of the oral mucosa is a single or multiple lesion. Papillomatosis is likely to
give rise to squamous cell cancers.
b) Benign tumors of glandular epithelia
Macroscopically, these tumors protrude into the oral cavity.
Histopathological examination of an adenoma shows an increased number of glandular cavities.
Microscopic examination specifies the histological type of
adenoma (tubular, villous, tubulovillous) and assesses possible dysplasia. Indeed, certain forms are likely to give rise to carcinoma.
Benign tumors of glandular parenchyma are nodular lesions
formed by a proliferation of glands, called adenomas .: Single or multiple (we then speak of adenomatosis).
Adenomas develop in the glands: e.g. parotid
2. CARCINOMAS
1/ Definition:
The term carcinoma (or epithelioma) refers to malignant tumors developed from epithelial structures: lining epithelia (malpighian, cylindrical) or glandular parenchyma.
a) Carcinomas of the epithelial linings
1. Squamous cell carcinomas
General
These malignant epithelial tumors (carcinomas) reproduce in a more or less elaborate way the structure of a malpighian epithelium and most often arise in a covering epithelium of this type .
Therefore, they are found in the skin, in the malpighian mucosa of the digestive tract (oral cavity, esophagus, anal canal), and in the malpighian mucosa of the female genital tract (exocervix, vagina, vulva).
Squamous cell carcinomas can also develop on glandular epithelia and then constitute metaplastic carcinomas .
EPITHELIAL TUMORS
Macroscopic aspects
The macroscopic characteristics of these tumors, although non-specific, are
important to know to interpret data from radiological examinations and
endoscopic. In advanced forms, whatever the location, we distinguish:
- vegetative (or budding) tumors : the tumor mass more or less
large protrudes from the skin covering or into the lumen of an organ.
- ulcerated tumors : the ulceration (loss of substance) is more or less deep and wide, often surrounded by a tumor ridge. Pure ulcerative forms are rare, they are most often associated (ulvero-vegetative, ulcero-infiltrating tumors).
- infiltrating tumors : the tumor invades the organ from which it originates
develops, leading to thickening, rigidity and stenosis. It is also important to know the early macroscopic aspects, for the purpose of early detection. A small frosted area of a mucosa, a telangiectatic area, a
simple superficial erosion should prompt additional examinations
cytological and/or histological in order to confirm or rule out the diagnosis of cancer.
Histological aspects
The tumor is made up of lobules (more or less rounded masses) and trabeculae, distributed
within a stroma of variable abundance, more or less inflammatory. The cells
tumors present more or less manifest cytological criteria of malignancy.
Depending on the degree of differentiation of the tumor, it will reproduce more
or less exact the appearance of a malpighian epithelium.
- well-differentiated squamous cell carcinomas : the lobules have cubic and basophilic cells on the periphery that resemble the cells of the basal layer of the epidermis, in the center larger, polygonal cells, between which we observe union bridges, thus resembling the mucous body of Malpighi.
- poorly differentiated squamous cell carcinomas : the lobules are made up of tumor cells which most often retain the appearance of basal cells of the epidermis, sometimes beginning to show the beginnings of differentiation.
To this notion of differentiation is classically added that of maturation.
designating a keratinization process (ortho-, para- or dyskeratotic)
Special case of skin cancers
Common in white subjects, they occur mainly on the
uncovered areas exposed to UV rays (lips, face, temples, ears, back of the hands). Certain professions are particularly exposed (sailors, farmers). Skin cancers (lips) sometimes occur on pre-existing lesions (radiodermatitis, chronic inflammatory lesions, xeroderma pigmentosum, etc.). Their accessible location most often allows early detection.
The clinical, histological and evolutionary characteristics make it possible to distinguish two large anatomo-clinical groups: squamous cell carcinomas and basal cell carcinomas.
- Squamous cell carcinomas
Macroscopically, the most common form is the ulcerative-vegetative form. There are also pure vegetative forms (“cutaneous horn”).
Histologically, it is a well-differentiated squamous cell carcinoma, often
mature. In the tumor lobules, the cells form a caricature of the epidermis: basaloid cells on the periphery, cells resembling a Malpighian body with intercellular union bridges (or spines), which may or may not be associated with maturation.
Evolution: squamous cell carcinomas tend to spread locally and
lymphatic invasion with lymph node metastases. Visceral metastases are, however, exceptional.
EPITHELIAL TUMORS
- Basal cell carcinomas
Macroscopically, the aspects are varied: ulcerated forms (the ulceration is surrounded by small tumorous elevations creating a “pearl” appearance), scarred form, pigmented form, etc.
Histopathology: The tumor cells, which all resemble the basal cells of the epidermis, form lobules appended to the deep surface of the epidermis. On the periphery, the cells adopt a characteristic palisade arrangement. There is no malpighian differentiation or maturation, but adnexal differentiation (pilar, sudoral or sebaceous) can be observed.
Evolution: it is always slow and strictly local, without metastasis. However, a
neglected or incorrectly treated ulcerated form can present a local boring evolution, responsible for significant mutilations.
- Squamous cell carcinoma in situ (Bowen’s disease)
Macroscopically, these are well-defined, erythematous lesions, sometimes
hyperkeratotic. On the mucosal side, these lesions are clinically designated by the term leukoplakia.
Microscopic examination shows intraepithelial changes with a
architectural disorganization, cytonuclear atypia, basal cell hyperplasia and dyskeratosis.
Evolution: these lesions can give rise to invasive squamous cell carcinomas.
2. Carcinomas of the glandular mucous membranes
The macroscopic aspects are superimposable on those of squamous cell carcinomas (vegetative, ulcerated, infiltrating forms or combination of the previous ones).
Their histopathological appearance is comparable to that of adenocarcinomas developed within glandular parenchymas.
3. Carcinomas of the glandular parenchyma
All glandular parenchymas, exocrine or endocrine, can be the site of carcinomas.
- Macroscopic aspects
Carcinomas of the glandular parenchyma are often nodular. These poorly defined nodules, single or multiple, of variable size and coloration, are sometimes altered by necrotic or hemorrhagic areas.
Particular forms are classically described: cystic and vegetative form and scirrhus whose hardness and retractile character are due to the abundance of fibrous stroma.
- Histological aspects
As with all tumors, differentiation, i.e. the degree of resemblance to normal reference tissue, allows us to distinguish between well, moderately and poorly differentiated adenocarcinomas.
Well-differentiated adenocarcinomas : the cells form groupings of varied appearance, close to normal structures: glands, tubes, papillae, acini, vesicles, trabeculae.
Moderately and poorly differentiated adenocarcinomas
It is important to emphasize from the outset the great polymorphism of the histological aspects encountered within the same tumor. For example, we can observe polyadenoid or cribriform masses, vast areas of mucus containing independent cells or cells organized in trabeculae (mucosal colloid carcinoma), independent cells “in a bezel ring” where the cytoplasm is deformed by a voluminous mucus vacuole which pushes the nucleus to the periphery.
Undifferentiated carcinomas
Microscopic examination and complementary techniques make it possible to confirm the epithelial nature of the tumor, but the epidermoid or glandular differentiation cannot be specified.
Simple histochemical techniques make it possible to obtain in many cases a
orientation. Mucosecretion, in favor of glandular differentiation of the tumor, can be demonstrated by special stains such as PAS, mucicarmine or alcian blue.
Immunohistochemistry confirms the epithelial nature of the tumor (epithelial markers: EMA, KL1). It can also guide the search for a primary cancer when a poorly differentiated carcinoma is discovered. For example, the phenotype established from panels of cytokeratins of different molecular weights can, to a certain extent, guide additional examinations towards an origin
Adenocarcinoma in situ
By definition, they are limited to the epithelium that gave rise to them and do not cross the basement membrane .
In practice, asserting their non- invasive nature is sometimes tricky, due to the very large contact surface between the epithelial structures and the connective tissue. Complementary techniques can again prove useful, such as PAS staining which highlights the basement membranes.
EPITHELIAL TUMORS
Wisdom teeth can cause infections if not removed.
Dental crowns restore the function and appearance of damaged teeth.
Swollen gums are often a sign of periodontal disease.
Orthodontic treatments can be performed at any age.
Composite fillings are discreet and durable.
Composite fillings are discreet and durable.
Interdental brushes effectively clean tight spaces.
Visiting the dentist every six months prevents dental problems.