PAGET’S DISEASE

INTRODUCTIONPaget’s disease is named after Sir James

Paget , an English surgeon who described the clinical course of this disorder under the name of osteitis deformans

Paget’s disease is characterized by excessive and abnormal remodeling of bone

The excessive remodeling gives rise to bones that are extensively vascularized, weak, enlarged and deformed with subsequent complications

Common in middle aged and elderly patients

ETIOLOGYEtiology of Paget's disease is still unknown But possible etiology include Genetic Viral infection Inflammatory cause Autoimmune disorders Connective tissue and vascular disorders

CLINICAL FEATURESPrevalence of Paget's disease increases with ageMost commonly diagnosed after 50 years and

rarely in people younger than 20 yearsSystemic findings include: almost all bones can

be involved The major characteristic is enlargement of

affected bone Patient complains of bone pain perceived as a dull

constant aching pain deep below the soft tissues The involved bones becomes warm to touch

because of the increased vascularity Non specific headaches, impaired hearing and

tinnitus are common symptoms of Paget's disease

ORAL MANIFESTATIONS include Involvement of jawsMaxilla exhibits progressive enlargement, the

alveolar ridge becomes widened and palate is flattened

If teeth are present, they become loose and migrate, producing some spacing

When mandible is involved, findings are similar but not usually as severe as in maxilla

As disease progress, mouth may remain open, exposing teeth, because the lips are too small to cover the enlarged jaw

Edentulous patients complain of inability to wear dentures because of increasing tightness due to expansion of jaw

Increase in the size of maxillary alveolar bone and drifting of teeth

Enlargement on the right maxilla. Patient was unable to use denture

Paget’s disease in 67 yr old woman showing enlargement of maxilla and protrusion of upper lip. Also there is deformity present at the root of the nose

HISTOLOGICAL FEATURESPaget's disease is characterized by enhanced

resorption of bone by giant multinucleated osteoclast with formation of disorganized woven bone by osteoblast

this process evolves through various phases of activity, followed by a quiescent stage

Hence, Paget's disease consist of following 3 phases: Lytic Mixed lytic and blastic Sclerotic or burned out Initial osteolytic phase is marked by disordered areas of

resorption by an increased number of overtly large osteoclasts (these abnormal osteoclast consist of as many as 100 nuclei)

The next osteoblastic phase follows with haphazard laying of new bone matrix and formation of woven bone

Repeated episodes of bone removal and formation results in appearance of many small irregularly shaped bone fragments that appear to be joined in jigsaw or mosaic pattern with deeply staining hematoxyphilic reversal lines. This pattern is histologic hallmark of Paget's disease

Osteoblastic phase includes excessive abnormal bone formation causing more compact and dense bone

The Paget's bone is coarse with an affinity for calcium and phosphorus Marrow spaces are filled with loose highly vascularized connective

tissue- this causes increase in the regional blood flow and thus leads to rise in skin temperature seen clinically

Pagetic bone shows no tendency to form haversian systems or to centre on blood vessels; the bones are very hard and dense

Eventually osteoblastic activity diminishes and osteoporotic or burned out phase predominates

The new bone is disordered, poorly mineralized and lacks structural integrity

The proliferation of bone and concomitant hypercementosis sometimes results in obliteration of PDL

Histology of Paget's disease shows several bone spicules in highly vascularized connective tissue stroma

Higher magnification : A- osteoclast in howship lacunaeB- osteoblast in process of bone formation

MOSAIC PATTERN IN PAGET’S DISEASE

RADIOGRAPHIC FEATURES In Paget's disease, there is initial phase of

deossification and softening, followed by bizarre, dysplastic type of reossification

Osteoblastic areas are opaque radiographically and patchy in distribution

Poorly defined areas of osteoporosis are notedLoss of normal trabeculation and appearance of

irregular osteoblastic activity gives rise to typical cotton wool appearance of Paget's bone

Teeth and adjacent bone also show radiographic changes : pronounced hypercementosis and loss of well defined lamina dura

Root resorption is reported in some cases but it is unusual

Radiographic image shows typical cotton wool appearance in Paget's disease

Hypercementosis and loss of lamina dura

TREATMENT AND PROGNOSISThere is no specific treatment for Paget's disease Very promising results have been recently

obtained in treatment of this disease by use of CALCITONIN, the parathormone antagonist produced by thyroid gland which suppresses bone resorption

BIPHOSPHANATES are also used since they inhibit bone resorption and as well as bone mineralization

One of the cytotoxic antibiotics, MITHRAMYCIN has been used therapeutically but has serious side effects