PAGET’S DISEASE

INTRODUCTION

• Paget’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

ETIOLOGY

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

CLINICAL FEATURES• Prevalence of Paget's disease increases with age• Most commonly diagnosed after 50 years and rarely in people

younger than 20 years• Systemic 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 jaws• Maxilla 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 FEATURES• Paget'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 noted• Loss 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 PROGNOSIS• There 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