Enlivening the radiographic features of Paget disease
- Vaishnavi Muthukumaran ,
- Subadra Kaliyaperumal and
- Aravind Warrier
- Oral Medicine and Radiology, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
- Correspondence to Dr Aravind Warrier; dentalwarrier@gmail.com
Abstract
Paget disease often presents as a rare asymptomatic lesion of the bone until it progresses into the advanced stages. A senile man was diagnosed with Paget disease of bone on routine dental radiographic analysis. His history of fractures, periodical ill-fitting dentures and frequent pain in the long bones were contributing to the diagnosis. The patient was referred to a general physician where whole body radiographs were taken, which showed several of the classic features of Paget disease. Biochemical analysis was also done in which serum alkaline phosphatase was elevated with all other values within normal limits, confirming the diagnosis. The patient was treated with single-infusion bisphosphonate followed by other required dental procedures. Early diagnosis and prompt management gave a good prognosis, preventing the potential complications.
Background
Paget disease results due to focal alteration of bone remodelling which alters the normal architecture of the bone. It is sometimes accidentally discovered through the finding of elevated serum alkaline phosphatase (SAP) activity on a biochemical screening and on radiographic investigations.1 This case report is one such in which patient was diagnosed with Paget disease of bone (PDB) on routine orthopantomography and symptomatically managed.
PDB is a chronic, non-inflammatory skeletal disorder that occurs in approximately 3%–4% of the population and relatively found to be more common in older people aged over 50 years with a slight male predilection.2 The radiographic finding is a keyhole to rule out the extent of the disease, which is characterised by cortical thickening and expansion of bone, patchy areas of sclerotic bone given a cotton wool appearance to the skull, with elevated SAP levels.2 3 In the orofacial region, the maxilla is involved more commonly than the mandible and results in enlargement of the middle third of the face and can sometimes simulate leontiasis ossea (lion-like deformity) in extreme cases. Our case report highlights the clinical and cardinal radiographic features of Paget disease.3
Case presentation
A senile patient came with bleeding gums and bad breath for the past 3 months. He also had head and lower back pain for the past 1 week. The patient had a history of right forearm and humerus fractures for which ORIF plating was done 13 years ago. He also gave a history of periodical ill-fitting fixed partial dentures and removable partial dentures for the past 2 years. The patient was conscious and well oriented with all vitals within normal limits. Extraorally, frontal bossing was evident with positive scalp vein sign and prognathic mandible was seen. Intraorally, class III malocclusion, generalised oedematous gingiva with tenderness on percussion in relation to 34, 35, 44, 15 and 27 tooth number and grade I mobility in right maxillary canine were noted. Hence, by correlating the history and clinical features, the patient was provisionally diagnosed with chronic generalised periodontitis.
Investigations
Orthopantomogram revealed generalised bone loss with periapical radiolucency in relation to 15 and 16 tooth number and an irregular trabecular pattern in mandible (figure 1). This incidental abnormal trabecular pattern made our next move for lateral skull view which showed several areas of focal sclerosis that produce ‘cotton wool appearance’ and diffuse calvarial thickening (figure 2A,B). All baseline investigations were within normal limits. Further, his biochemical tests revealed normal serum calcium (9.2 mg/dL) and serum phosphorus (4 mg/dL) but elevated SAP level (881 IU). Hence, radiographic diagnosis was put forth as Paget disease. Consequently, the patient had been advised to get general physician opinion for the same. Radiographs of the pelvis (figure 3) and lumbar spine (figure 4) were explicated to determine the activity and distribution of the disease in which the ‘pelvic brim sign’ and ‘picture frame vertebra’ were affirmative, respectively.
Orthopantomogram showing an irregular trabecular pattern in mandible.
(A) Lateral skull view showing typical ‘cotton wool appearance’. (B) Thickening of calvarium.
Pelvis showing ‘pelvic brim sign’ identifiers of the mixed lytic mid-phase of the disease.
Lumbar spine showing ‘picture frame vertebra’.
Treatment
He was treated symptomatically with single intravenous infusion of zoledronic acid injection 4 mg along with calcium and vitamin supplements. Teeth 34, 35, 44, 15, 27 and 13 were scaled and root planed with curettes and an ultrasonic scaler, followed by adjunctive treatment with a 5-day course of systemic azithromycin. It was advised to enhance attachment gain and improve the odds of avoiding periosteum-exposing periodontal surgery.
Outcome and follow-up
Paget disease has no curative treatment but disease progression can be controlled, along with reduction of the symptoms. Likewise, this patient had complete relief from his joint pain at the re-evaluation appointment after 3 months and presented a high standard of oral hygiene. Further, follow-up was unworkable due to the patient’s senility and low economy. The patient is hale and healthy to date.
Discussion
PDB is the paradigm of a focal bone disorder with increased bone turnover.4 It is a non-inflammatory, metabolic, skeletal disorder characterised by excessive osteoclastic bone resorption that is followed by compensatory increased osteoblastic activity leading to unstructured, fibroblastic and biomechanically unstable bone.5 It has a higher prevalence in people of British descent and rarely affecting the Indian population with a prevalence rate of 0.066%.3 With respect to the involvement of bone, two major forms are defined as monostotic (>17%) and polyostotic.2 It is a geriatric disease principally affecting patients of above sixth decade; however, it can affect any age group, including infants (juvenile Paget or infantile hyperphosphatasaemia).3 5 Men are 1.5 times more commonly affected than women.6 The age and gender of our case are consistent with the literature. After osteoporosis, PDB is the second most common bone disease.2 Viral infection (environmental factors) and genetic hypotheses are currently most credited as the cause.4 The most common skeletal lesions occur in the pelvis, femur, spine and skull. Other common sites include the tibia, humerus, clavicle and scapula.6 Bowing of long bones, kyphotic deformity, platybasia and hearing loss are features of this disease.6 7 Facial disfigurement may be a consequence of enlargement of the maxilla and/or mandible with the ratio of 2:1.2 Maxilla exhibits progressive enlargement; teeth changes include loss of lamina dura, hypercementosis, ankylosis or mobile and migrate, producing spacing.3 8 The alveolar ridge becomes widened and palate is flattened leading to difficulty in using dentures.2 With immense involvement of jaw and facial bones, deformation may lead to leonine features (leontiasis ossea) similar to those in fibrous dysplasia, but the latter is seen in patients younger than 40 years of age and often has unilateral distribution.4 Similar features of hearing loss (R>L), enlarged mandible with mobile and migrated tooth-producing space with frequent ill-fitting dentures due to widened ridge were consistent with our case. Many of these bones where Paget disease commonly occurs have characteristic radiographic features.4
Biochemical findings include elevation of the SAP secondary to intense osteoblastic activity, which is compatible with our case, and elevation of urinary hydroxyproline secondary to excessive collagen turnover. Serum calcium and phosphorus concentrations are usually normal. Elevated serum calcium and hypercalciuria and the possibility of developing renal stones typically occur following gross fracture and confinement to bed. The radiological features (table 1) reflect the histological findings throughout the three (incipient, mid and late) phases of the disease.4 9 In the incipient phase, osteoclastic activity is predominant; in the mid-phase, both osteoclastic and osteoblastic activities (osteoblastic activity being predominant) as in our case; and on progressing to late phase, osteoblastic activity declines. The mixed phase illustrates all four cardinal features of the disease comprising advancing osteolysis (‘V cutting cone’, ‘blade of grass’, ‘flame-shaped’), coarsening and accentuation of bony trabeculae along the lines of stress, cortical thickening and osseous widening.4 9
Radiographic phases of Paget disease4 9
Histologically, atypically enlarged trabeculae disclose the mosaic pattern of reversal lines that have been formed due to continuous bone deposition escorted by concurrent disordered bone resorption. The end stage of the disease shows a classic jigsaw puzzle or mosaic pattern of cemental lines.4 9
Among the bisphosphonates, zoledronic acid is very effective in decreasing the disease activity. A single infusion of 5 mg is administered for 15 min, whereas potent oral bisphosphonates require 3–6 months to normalise bone turnover.10 11 This adds up the possibility of a substantial increase in the convenience of treatment and with its greater efficacy increases the prognosis and duration of remission. Morbidity is in direct proportion to: (a) the number of bones involved, (b) the degree of bone enlargement, (c) weakening and (d) deformity.5
Complications of fracture, arthropathy, nerve entrapment and malignancy (probably osteosarcoma, fibrosarcoma and chondrosarcoma) may be seen.4 The higher chance of malignant transformation of 5%–10% in polyostotic disease is reported.7
Patient’s perspective
I had visited oral physician for my bleeding gums where I was asked to take a x-ray that covers all my teeth and jaws. I had also pain in my legs, joints and head which I noticed in the last 3 months. I was not worried and I moved on thinking it to be an age-related suffering. Later I was told by my dentist that I have a bone disorder which scrapes off my bone gradually causing pain in my bone, dislocation and frequent fractures. This stroked me of my previous history of back-to-back fracture of my forearm and leg was due to this disease. I was referred to general physician, my blood samples were taken and I was asked to get admitted for the treatment course. As per the doctor’s advice I was treated and after 2 weeks of time my tooth problem was also managed by the oral physician. My heartful thanks to the oral physician and the general doctor who had let me know the disease that attacked my bones and managing it accordingly. Lifting me to live for more years with the trust in almighty.
Learning points
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Oral physicians play a major role in diagnosis of various diseases that have multifocal presentations in the head and neck domain.
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Paget disease of bone has excellent prognosis if it is diagnosed and treated early in the course of the disease before the complications occur.
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Routine haematological and radiographic investigations should be given prime importance as they act as a small keyhole for the wholesome care.
Ethics statements
Patient consent for publication
Footnotes
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Contributors VM is involved in patient care, follow-up, documentation of treatment details and manuscript writing. AW contributed to patient follow-up, manuscript formatting and manuscript revision. SK has contributed to patient management, literature search, manuscript detailing and revision.
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
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Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
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Competing interests None declared.
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Provenance and peer review Not commissioned; externally peer reviewed.
- © BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.
References
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