benign tumors (TB) epithelial :
Interest to the different epithelial tissues :
• coatings : epidermis and mucous membranes
• solid organs (parenchymes).
These epithelia being 2 types : epidermoid (or squamous) and glandular.
• TB of squamous : papilloma
• TB glandular epithelium : adenoma.
These are benign tumors of the skin and mucous epidermoid.
1- Seat :
– skin – mucous :
– digestive tract : mouth, pharynx, esophagus, anus
– upper half of the larynx – vagina and external part of the cervix.
NB : the epithelium of the urinary tract is near, but a little different from the squamous epithelium. he is called “transitional” or urothelial.
2- Histology of squamous epithelia normal :
These are epithelia multistrata comprising :
• a layer of small basal cells, based on the basal membrane
• a layer of intermediate cells, with more abundant cytoplasm
• a layer of surface cells that are shed.
• At skin level, superficial cells are keratinized.
• In mucosal, they are rich in glycogen.
3- Macroscopie :
• usually small tumors, projecting, appearance of raspberry.
• Sometimes larger, with a cauliflower appearance : condylome, especially at the genital and anal mucous membranes, where they have a viral origin (papillomavirus) : “cockscomb”.
Genital warts are sometimes plans and sometimes multiple : papillomatosis (genital, laryngeal, nasal cavity)
4- histology :
The squamous form folds, corresponding to the taste buds seen with the naked eye.
At each of the papillae, the organization of the epithelial layer is well preserved.
The basement membrane is intact.
The intermediate layer is thickened cells.
In skin papillomas, the keratin layer is thickened (papillomas horny).
Aspect cytologique : all cells are normal in appearance, without atypical nuclei, without abnormal mitosis.
5- Evolution :
Most of these tumors are benign and will not recur after exeresis.
Some however are precancerous and can develop into cancer : squamous cell carcinoma : genital warts Plans papillomatosis some upper airway papillomas “transitional” bladder are rarely true benign tumors.
They recur and progress to carcinoma.
Histological grading, estimating their malignant potential, applied to them.
B – adenomas :
These benign tumors of glandular epithelia.
1- See and normal histology :
a- mucous :
– digestive tract : stomach, duodenum, small intestine, colon, rectum
– female genital apparatus : oviducts, endometrial, endocol
– airway : nasal cavity, trachea, bronchi
Their histological structure to oppose the squamous epithelia : unistratifiés epithelium having a mucus secretion and flexuosities, variable depth, which penetrate the connective tissue : glandular crypts or glands.
Glandular mucosa is constituted by all : crypts + connective tissue (chorion).
Its structure is more complex than that of a squamous mucosa.
b- Parenchymes :
• Glandes exocrines : his, exocrine pancreas, prostate, salivary glands.
The glandular cells form acini : they sit around a drained cavity through a channel
• Endocrine Glands : adrenal, endocrine pancreas, parathyroide, thyroid, foie.
The cells form bays separated by capillary, except in the thyroid where they are arranged in vesicles.
2- Adenomas mucosal :
a- Macroscopie :
Appearance of polyp : tumor rounded attached to the wall by a pedicle more or less individualized.
The term polyp is actually purely macroscopic : “pedunculated tumor developed in a hollow body”.
All polyps are adenomas : there are inflammatory polyps, retentional of polyps, Original polyps dysgenetic. Seat adenomatous polyps :
– Mostly, digestive tract : colon +++
– More rarely : stomach, duodenum, small intestine
– sometimes multiple, in some cases having a familial : polyposis colorectal or familial adenomatous.
– More rarely, cervix, endometrial, bronchi.
b- Histology and evolution :
Increase in the glandular cavities, separated by connective chorion more or less abundant.
adenoma cells are normal theory
In fact, some adenomas (colon +++) are precancerous lesions, and consists of glandular cells comprising cytological abnormalities, appreciated by a grading (dysplasia).
The malignant potential justifies endoscopic screening and removal of adenomatous colon polyps, especially in families at risk.
In the family adenomatous colonic, transformation occurs in cancer 100% cases preventive treatment is colectomy, during teenagehood.
3- Adenomas parenchyma :
a- macroscopie :
Single or multiple nodules (adenomatosis) rounded, very limited, readily cleavable Headquarters :
– His : fibroadenoma: adenomatous the cavities are surrounded by a proliferation of fibroblasts, with collagen production
– Prostate : adenomyoma: combination with proliferation of smooth muscle.
– Salivary glands : pleomorphic adenomas : association with various connective tissue proliferations: myoepithelial cells, cartilage …
b- histology :
Increase in the glandular cavities, sometimes dilated.
The cells are normal.
• In the exocrine glands : adenomas are often associated with connective tissue proliferation: Note : hormonal imbalance is causing fibroadenomas of the breast and prostatic adenomyomas, considered by some as “pseudo-tumor lesions”, hyperplasiques.
• In endocrine glands : adenomas keep normal trabecular architecture.
The cells do not contain misstatements.
He can be very difficult, or even impossible, of histologically distinguish hyperplasia adenoma, better individualized by macroscopic.
Endocrine adenomas can be : non-secreting, revealed by the increase in volume of the organ secreting: revealed by a hormonal hypersecretion clinical syndrome :
Examples : parathyroid adenoma : hypercalcemia adrenocortical adenoma : hypercorticisme (syndrome de Cushing) ante-pituitary adenoma : acromegaly …
Benign conjunctive :
– histology normal :
• common connective tissue (fibroblasts and collagen), present throughout the body.
• Connective tissue differentiated, with different functions: adipose tissue, vessels, the, cartilage, muscle …
The variety of specialized connective tissue does not allow a common name.
To designate a benign connective tissue neoplasm, was added the suffix ome, on behalf of the normal histological structure.
The malignant tumor of the same fabric is designated by adding the suffix sarcoma.
A – fibroids :
benign tumors of connective tissue common.
1- Macroscopie :
Nodule well limited
– Chorion mucosal
– Kidney variable Headquarters.
In particular, abdominal wall.
2- histology :
Bundles of spindle cells, with scant cytoplasm, abundant collagen, many ships.
Absence of abnormal cells and mitoses.
• Myxomes : soft tumors, gelatinous, correpondant a proliferation of fibroblasts associated with an abundant intercellular substance. frequent recurrence.
• fibromatoses : fibroblast proliferation or infiltrating with multiple nodules.
Evolution : habitual relapse.
B – Lipomes :
benign tumors of adipose tissue.
• Seat: very variable. Most of the time, subcutaneous
• Macroscopie : nodules mous, yellowish ; very variable in size, sometimes large.
• histology : adipocytes normal grouped into lobules. They are sometimes, associated with fibrous tissue or vessels.
C – Angiomes :
Benign tumors of the vessels.
TB blood vessels : hemangiomas TB of the lymph vessels : lymphangiomes
• Macroscopie : lesions poorly defined.
• Seat : subcutaneous tissue or viscera.
• histology : 2 types of hemangiomas :
– cavernous hemangiomas : formed vascular cavities large
– capillary hemangiomas : made up of small vessels joined.
Lymphangioma are of the cavernous.
Hemangiomas are actually considered birth defects, rather than tumors.
They are sometimes multiple : angiomatoses.
We meet them in congenital diseases (Von Hippel Lindau …)
Severity of cerebral hemangioma, responsible for bleeding.
D – Leiomyomes :
benign smooth muscle tumors.
• Macroscopie : well limited nodules, whitish, fascicles.
• Seat:especially uterus (myometrium) more rarely, paroi digestive, or dermis.
• histology : bundles of fusiform cells having a relatively abundant eosinophilic cytoplasm. no cell abnormalities.
It is in the womb, a hormonally sensitive lesion (estrogen), dystrophic nature rather than tumor.
E – Rhabdomyomes :
Benign tumors of striated muscle Very rare Headquarters : larynx, pharynx and heart (child).
F – Chondromes :
Benign tumors of cartilage
Seat : small bones of the hands and feet.
Nodules intraosseous, consist of apparently normal cartilage. sometimes multiple : chondromatose.
G – osteoma :
Benign tumors of the bone tissue.
Rares : bone to make
H – Schwannomes :
Benign tumors of Schwann cells
Seat : highly variable : path of a nerve.
whitish nodule, fa.
histology: bundles of spindle cells.
The arrangement of cores “palisade” differentiates a schwannoma of a fibroid or leiomyoma.
mesenchymal tumors Grading Issues :
from 2 types :
A – determining the exact histological type :
Sometimes very difficult to be specified by morphology alone.
Diagnosis is possible by immunohistochemistry, to detect the expression of tissue markers :
– vimentine (intermediate filament common to the connective cells)
– smooth muscle α-actin
– S100 protein (cellules de Schwann).
B – distinction of malignancy (sarcoma) :
sometimes difficult, because some sarcomas have little cellular atypia and mitotic.
Benign tumors exist they really ?
Several types of epithelial and connective TB are considered :
• dystrophic lesions (hyperplasies) due to hormonal imbalance : adenomyoma prostate, fibroadenomas to be, uterine leiomyoma
• birth defects : angiomes
• epithelial hyperplasia viral : papillomas, condylomes
• precancerous conditions : colonic adenomas, genital warts.
The classic group “benign tumors” is probably composed of heterogeneous lesions : some are not true tumors other corresponding to the early stages of cancer. Their morphological and evolutionary similarity (although limited lesions, usually of local development) however still justifies their grouping, their exact pathophysiology is not yet fully known.