Fibrous dysplasia is a chronic problem in which scar-like tissue grows in place of normal bone. It often results in one or more, of the following: Bone deformity. Brittle bones.
It is also called as ‘African jaw lymphoma’. It is a lymphoreticular cell malignancy. In the African form jaw involvement is 75% and in cases of the American form, abdomen involvement is more common. It is a B-cell neoplasm.
• Epstein-Barrvirus(EBV)which also causes nasopharyn- geal carcinoma and infectious mononucleosis is considered to be the etiological factor. There are higher EBV antibody levels in patients of Burkitt’s lymphoma.
- Age and sex—peak incidence is in children between 6to 9 years. Males are affected more commonly than the females, with a ratio of 2:1.
- Site distribution—more are found in maxilla than in mandible, where it may spread rapidly to the floor of the orbit. Almost always occurs in molar area. In the African form, more than one quadrant is involved while in the American form, only one quadrant is involved.
- Onsetandprogress—the most important hall mark of this tumor is the fast growth with a tumor doubling time of less than 24 hours.
- Symptoms—the most common presenting features are swelling of the jaws, abdomen and paraplegia. It is painless.
- Sign—peripheral lymphadenopathy is common.
- Prognosis—it is rapidly fatal in the absence of treatment,with death occurring within 6 months.
- • Onset and extent—it begins generally as a rapidly growing tumor mass of the jaws, destroying the bone with extension to involve maxillary, ethmoid and sphenoid sinus as well as orbit.
- Symptoms—loosening or mobility of permanent teeth.There is gross distortion of the face due to swelling. Paresthesia and anesthesia of inferior alveolar canal or other sensory facial nerves are common.
- Signs—gingiva and mucosa adjacent to the affected teeth become swollen, ulcerated and necrotic. As the tumor mass increases, the teeth are pushed out of their sockets. Swelling of the jaw occurs and it may cause facial asymmetry. They are capable of blocking nasal passages, displacing orbital contents and eroding through skin. There is derangement of arch and occlusion. There may be large quantity of mass protruding into the mouth, on the surface of which may be seen rootless, developing permanent teeth.
- Spread—once the tumor perforate the bone, it is initially confined by the periosteum, but subsequently it spreads to the soft tissues of the oral cavity and face where rapid tumor growth soon obliterates the entire face and skin becomes tense and shiny.
Shows characteristic starry sky appearance.
- Radiographic Features
- Motheaten appearance—small radiolucent foci scattered throughout the affected area. These small foci coalesce and form a multilocular moth eaten appearance.
- Sunray appearance—if periosteum is elevated, it will produce sunray appearance.
- Margins—margins are ill defined and non-corticated.
- Shape—they expand rapidly and are ballooned shaped.
- Teeth—Lesions are osteolytic with loss of lamina dura about the erupted teeth and crypts of developing teeth are enlarged.
- Effect ons urrounding structures—they expand very rapidly and breach its outer cortical limits.
- • Clinical diagnosis—swelling of the jaw and abdomen with peripheral lymphadenopathy can give clue to the diagnosis.
• Radiological diagnosis—moth eaten appearance is seen with loss of lamina dura around the teeth.
• Laboratorydiagnosis—monotonous sea of un differentiated monomorphic lymphoreticular cells, usually showing abundant mitotic activity. There is also hyperchro- matosis and loss of cohesiveness. Characteristic ‘starry sky’ appearance is seen.
• Cytotoxicdrugs—cytotoxicdrugs like cyclophosphamide 40 mg/kg in single IV administration and repeated about 2 weeks later. Vincristine and methotrexate have been successful in some cases.
• Multiagent chemotherapy—combination of drugs such as cyclophosphamide, vincristine and methotrexate give better results than any single drug. Majority of patients show dramatic response to the therapy. The swelling regresses and the displaced teeth return to their normal position within 1 to 2 weeks.
REFERENCE- SHAFER’S TEXTBOOK OF ORAL PATHOLOGY AND ANIL GHOM TEXTBOOK OF ORAL MEDICINE
THREE CARTILAGE TYPES
Hyaline, elastic, and fibrocartilage
- Cartilage type is determined by matrix and fiber components.
The most common type in the body.
- Glassy, pink-staining, gel-like matrix comprises a ground substance of proteoglycan aggregates, chondronectin, and water.
Isogenous groups of chondrocytes are housed within lacunae; the darker staining ring around the lacuna is the cartilage capsule.
Invisible type II collagen fibers.
- Sternal ends of the ribs, many articular surfaces, the tracheal rings, the larynx, and the nasal septum.
- Hyaline cartilage is also the skeletal precursor during development.
- At the articular surfaces, hyaline cartilage provides a smooth surface for free movement; elsewhere, such as in the nasal septum, it provides structural support.
Shares many similarities with hyaline cartilage.
- Very light staining
Chondrocytes in lacunae
Elastic fibers create a dark-staining network around the lacunae
- Auditory tubes, epiglottis, and external ear
- Elastic fibers provide flexibility with recoil; for example, when you bend your external ear, it moves easily, but snaps back into place when released.
Fibrocartilage (aka, fibrous cartilage)
Highly organized appearance.
- Tightly packed, thick bundles of type I and type II collagen fibers run in parallel.
Lacunae and chondrocytes lie in rows between the collagen bundles.
- Intervertebral discs, the pubic symphysis, and the joint capsules
- Provides tensile strength and resistance to compression; its dense nature allows it to bear a weight, as in the intervertebral discs.
BY Dr. KRITI NAJA JAIN :-
1. FIBROUS DYSPLASIA :-
Def:- Fibrous dysplasia is an uncommon nonhereditary, developmental anomaly of the bone due to a defect in osteoblastic differentiation and maturation.
- Microscopic finding of fibrous dysplasia show irregularly shaped trabeculae of immature (woven) bone in a cellular, loosely arranged fibrous stroma.
- The bone trabeculae are not connected to each other . They often assume curvilinear shapes.
- which have been likened to CHINESE script writing.
- The bone trabeculae are considered to arise by metaplasia and are not surrounded by plum appositional osteoblasta.
2. PAGET’S DISEASE (OSTEITIS DEFORMANS):-
Def:- Paget’s disease of bone is a condition characterized by abnormal and anarchic resorption and deposition of bone, resulting in distortion and weakening of the
- Microscopic examination shows an apparent uncontrolled alternating resorption and formation of bone.
- in the active resorption stages, numerous osteoclasts surround bone trabeculae and show evidence of resorption activity.
- Simultaneously ,osteoclastic activity is seen with formation of osteoid rims around bone trabeculae .
- A highly vascular fibrous C.T. replaces the marrow .
- A characteristic microscopic feature is the presence of basophilic reversal lines in the bone.
- These lines indicate the junction between alternating resorptive and formative phase of the bone and result in a ” JIGSAW PUZZLE” or “MOSAIC” appearance of the bone.
- In the less active phases ,large masses of dense bone showing prominent reversal lines are present.
3. CENTRAL GAINT CELL GRANULOMA(GIANT CELL LESION; GIANT CELL TUMOR):-
Def :- Central giant cell granuloma (CGCG) is an uncommon, benign and proliferative lesion whose aetiology is not defined. Central giant cell granuloma is a relatively common benign intraosseous destructive giant cell lesion, which often affects the anterior part of the jawbone. By seeing clinical and radiographically , CGCG is divided into two types:-
1. Nonaggressive lesions make up most cases, exhibit few or no symptoms, demonstrate slow growth, and do not show cortical perforation or root resorption of teeth involved in the lesion.
2. Aggressive lesions are characterized by pain, rapid growth, cortical perforation, and root resorption. They show a marked tendency to recur after treatment, compared with the nonaggressive types.
- Lesional tissue is composed of highly cellular connective tissue stroma with numerous spindle shaped cells.
- Multinucleated giant cells are distributed in this C.T.
- Mesenchymal cells
- Gaint cells are large with many nuclei upto 20 or more.
- Gaint cells are usually aggregated close to the blood vessels.
1.Maji Jose 2nd edition
BY: Dr.Kriti Naja Jain :-
*Lichen planus is a chronic mucocutaneous disorder manifested in a various forms in the oral cavity.
*The most characteristic pattern is” RETICULAR TYPE” with the interlacing white stripe called “WICKHAM’S STRIAE”.
- Histopathology FIRST DESCRIBED BY DUBRENILL 1906
- later revised by Shklar in 1972
- Hyper orthokeratinisation or hyper parakeratinisation
- ◦Thickening of granular layer
- ◦Acanthosis of spinous layer
- ◦Intercellular oedema in spinous layer
- ◦“ Saw-tooth” rete pegs
- ◦Liquefaction necrosis of basal layer- Max Joseph spaces
- ◦Civatte ( hyaline or cytoid) bodies
- ◦Juxta epithelial band of inflammatory cells
- ◦An eosinophilic band may be seen just beneath the basement membrane and represent fibrin covering lamina propria.
Pmphigus is a tissue specific autoimmune disease affecting the skin and mucosa. Clinical manifestations is in the from of “vesiculobullous lesions” that rupture to form ulcer and erosions .
*Vesiculobullous lesions develop due to immune mediated acantholysis causing intraepithelial vesicle formation.
- Formation of the vesicle or bullae within the epithelium that often results in a supra-basilar spilt or separation.
• Following this suprabasilar spilt in the epithelium, the basal cell layer remains attached to the lamina propria, and it often appears as a row-of-tomb stones.
• Loss of intercellular bridges and collection of edema fluid result in acantolysis within the spinus cell layer, which causes disruption of the prickle cells.
• As a result of acantholysis, clumps of large hyperchromatic epithelial cells desquamate that are often seen lying free within the vesicular fluid, these desquamated cells are often rounded and smooth in appearance and are known as “Tzanck cells”.
- Small number of polymorphonuclear neutrophil (PMN) and lymphocytes may be found within the vesicular fluid, but there is minimum inflammatory cell infiltration in the underlying connective tissue (unlike any other vesiculobullous lesion).
Pemphigoid is a vesiculobullous lesions that develop due to an autoimmune reaction directed against some components of basement membrane.
*This results in seperation of epithelium from the connective tissue with sub epithelial vesicles formation .
*Bullous pemphigoid and cicatricial pemphigoid are two different types of pemphigoid lesions.
- The inflammatory infiltrate is typically polymorphous, with an eosinophilic predominance.
- Mast cells and basophils may be prominent early in the disease course.
- Electron microscope shows basement membrane attached to the connective tissue rather than overlying separated epithelium.
- Tzanck smear shows only inflammatory cells.
- Sub epithelial vehicle formation.
- Intact epithelium without acantholysis.
- Pic – Maji Josh 2nd edition
source – don’t remember, had written it a lot time ago
Comprises three layers
- Endocardium, Myocardium, Epicardium
- Innermost layer of endothelial cells.
- Its function is to line the chambers and valves of the heart, creating a smooth surface to reduce friction with the blood.
- Site of endocarditis
- Muscle cells contract to pump blood from the heart; are arranged in bundles wrapped in connective tissue.
- Myoendocrine cells that produce atrial natriuretic peptide (aka, factor or hormone) in response to high blood pressure.
- Nodal cardiocytes control the rhythmic contraction of the myocardium (these cells are concentrated in the sinoatrial and atrioventricular nodes).
Details of cardiac muscle cells:
- Have 1-2 centrally located nuclei.
- Cells branch to connect with multiple adjacent cells.
This arrangement increases intercellular connections, which are marked by intercalated discs, for efficient signal conduction.
- Intercalated discs comprise interdigitating processes that hold adjacent cells together via complex junctions to rapidly spread contraction signals throughout the myocardium.
- Purkinje fibers
Are lighter in the center and lie nearer the endocardium than do muscle cells
Purkinje fibers are part of conduction system of the heart.
- Contributes to the serous layer of the pericardium, the protective sac that envelops the heart.
- Comprises simple squamous epithelium.
- Subepicardial connective tissue comprises adipose and other connective tissues, passage for coronary blood vessels and nerves.
Long, muscular tube delivers food from the pharynx to the stomach.
- Mucosa layer
- Comprises stratified squamous epithelium; layers of flattened cells provide protection against physical and chemical damage from the foods, liquids, and salivary juices traveling to the stomach.
- Muscularis mucosae is also visible in our sample.
- Submucosal layer
- Submucosal glands
- Glands of the submucosal and mucosal layers produce protective and lubricating mucous, which contributes to the protective barrier.
- Submucosa and mucosa form longitudinal folds in the relaxed esophagus; these folds expand to accommodate foods and liquids during swallowing.
- Muscularis externa layer
The composition of the muscularis externa layer changes along its length, as follows:
- The upper 1/3rd comprises skeletal muscle fibers in both the circular and longitudinal layers;
- The middle 1/3rd comprises a circular layer of skeletal muscle and a longitudinal layer of smooth muscle;
- Both layers of the lower 1/3rd, which opens to the stomach, contains smooth muscle fibers.
- The outermost layer of the esophagus is adventitia; once the esophagus passes through the diaphragm, and is no longer anchored to the body wall, it becomes serosa.
Connects with the esophagus, superiorly and the duodenum, inferiorly.
Regions of the stomach:
- Cardiac, where the esophagus and stomach meet
- Fundus, in the upper left corner
- Body, which is the largest region of the stomach
- Pyloris, which opens to the duodenum
Gastric Folds, aka, rugae
- Line the empty stomach; expand to accommodate foods and liquids during gastric filling
- Surface mucous epithelium
- These cells secrete mucous and form a physical and chemical barrier to protect the underlying stomach wall from stomach contents. In addition to ingested foods and liquids, the stomach wall is potentially vulnerable to the gastric juices it releases as part of digestion.
- Invaginations of the surface mucosal epithelium form pits, which open to glands deeper within the mucosa; depending on their location in the stomach, the glands produce mucous and/or gastric juices.
- Lamina propria is visible in our sample between the pits and glands.
- Slips of muscularis mucosae can be seen extending into the gastric fold.
- Cardiac and pyloric glands are primarily mucous-secreting; in other words, they do not produce significant quantities of gastric juices.
- Cardiac glands are highly coiled at their ends, or bases.
- Pyloric glands are highly branched.
- Gastric glands of the fundus and body produce both mucous and gastric juices; they are responsible for chemical digestion.
- Surface epithelial cells line the pit, and secrete surface mucous.
- Mucous neck cells also secrete mucous.
- Parietal cells, which appear as round, bulging, and light pink in the histological sample, are found within the neck and base of the gastric gland. These cells, which are also referred to as oxynitic cells, secrete hydrochloric acid and intrinsic factor (required for vitamin B12 absorption).
- Stem cells are also found within the neck; these cells play important roles in the constant renewal of gastric mucosal cells.
- Chief cells reside in the base of the gland, and stain darker due to secretory granules containing pepsinogen, which is a precursor to pepsin for protein digestion.
- Enteroendocrine cells, which is an umbrella term for a variety of cells that secrete peptide hormones. For example, G cells secrete gastrin, and D cells secrete somatostatin.
- The cells of the gastric gland lie on a basement membrane, which separates them from the surrounding glands and lamina propria.