Dentomaxillofacial Radiology (2006) 35, 50-54
© 2006 British Institute of Radiology
doi: 10.1259/dmfr/44987850
Pyle's disease: an incidental finding in a routine dental patient
VS Narayananan*,
L Ashok,
GP Mamatha,
A Rajeshwari and
SS Prasad
Department of Oral Medicine and Radiology, Bapuji Dental College and Hospital, Davangere – 577 004, Karnataka, India
*Correspondence to: Dr Veena S Narayananan, Department of Oral Medicine and Radiology, Bapuji Dental College and Hospital, Davangere – 577 004, Karnataka, India; E-mail: veesn{at}rediffmail.com
Received 23 December 2004;
revised 4 March 2005;
accepted 1 May 2005
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Abstract
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Pyle's disease (PD) or metaphyseal dysplasia is an extremely rare genetic disorder, transmitted as an autosomal recessive trait. The peculiarity of the disease is that the striking radiographic manifestations contrast with the relatively normal clinical features. The oral findings and radiographic features of the disease are not well documented. The present paper describes the radiographic features of Pyle's disease in a 17-year-old girl and draws attention to the findings in the jaw bones.
Keywords: Pyle's disease; metaphyseal dysplasia; multiple retained deciduous teeth; Erlenmeyer flask deformity
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Case report
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A female patient aged about 17 years reported to the Department of Oral Medicine and Radiology, Bapuji Dental College and Hospital, Davangere, India complaining of pain in the lower right molar region over 2–3 days. The pain was insidious in onset with dull aching, moderate intensity, intermittent in nature and increasing with chewing. Past medical history was insignificant except for a history of fracture of her lower right leg when she was 3 years of age. Her developmental milestones were normal, as reported by her mother. She had undergone oral prophylaxis and dental restorations 2 years previously. Her family history was insignificant.
On general examination she appeared moderately built and nourished. The right submandibular lymph node was enlarged, tender, soft and mobile. Mouth opening was within normal limits.
Intraoral examination revealed areas of depapillation of the tongue. Several permanent teeth were clinically missing (premolars in the right maxillary quadrant, canine and premolars in the left mandibular quadrant and canine and second premolar in the right mandibular quadrant). Multiple retained deciduous teeth (Figure 1
) were present which contributed to the crowding of teeth in the upper and lower arches.
Deep proximal caries was present on the mandibular left second permanent molar (37), right first permanent molar (46), right second deciduous molar (85) and all these teeth were tender to percussion. A working diagnosis of apical periodontitis in relation to the mandibular right first permanent molar was made.
Intraoral periapical radiographs revealed discontinuity of lamina dura and hazy radiolucency in relation to periapex of teeth 46 and 37 (Figures 2 and 3). Fine trabeculation of the alveolar bone was noted in both periapical radiographs. A panoramic radiograph, taken because of the multiple missing teeth, revealed multiple retained primary and unerupted permanent teeth as well as generalized rarefaction of jaws, fine, scanty trabeculations, thinning of cortices of mandible, wall of maxillary sinus and lamina dura and flared neck of the condyle (Figure 4).
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Figure 2 Periapical radiograph of mandibular right quadrant, showing deep caries in tooth 46 and discontinuity of the lamina dura and hazy radiolucency at the apex of that tooth
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Figure 3 Periapical radiograph of mandibular left quadrant, showing deep caries in tooth 37 and discontinuity of the lamina dura and hazy radiolucency at the apex of that tooth
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Figure 4 Panoramic radiograph showing multiple retained primary teeth and unerupted permanent teeth, and generalized rarefaction of the jaws, with fine, scanty trabeculations
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The radiographic differential diagnosis included metabolic bone disorders such as rickets, hyperparathyroidism, renal osteodystrophy and hypophosphataemia. However, the patient did not manifest clinical features of any of these disorders and a complete haemogram, serum calcium and phosphorous, and alkaline phosphatase values were within normal range.
The patient was referred to a general radiologist for a skeletal survey, which revealed striking radiographic changes.
The metaphyses of the lower end of both femora (Figure 5) showed widening and thinning of cortices and ground glass opacity of osteoid matrix, giving rise to "Erlenmeyer flask deformity". Diaphyses appeared spaced.
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Figure 5 Widening of the metaphyses of the lower end of both femora (Erlenmeyer flask deformity), thinning of cortices, and ground glass opacity of bone
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The tibia (Figure 6), fibula and humerus (Figure 7) also showed bone remodelling defect, with Erlenmeyer flask deformity of proximal tibia and upper third of both humeri. The fibula appeared widened with ground glass opacity.
Metacarpals (Figure 8) and phalanges (Figure 9) showed thinning of cortices and loss of corticomedullary differentiation and ground glass opacity of osteoid matrix.
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Figure 8 Metacarpal bones showing thinning of cortices, loss of corticomedullary differentiation, and ground glass opacity
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Figure 9 Thinning of cortices, loss of corticomedullary differentiation, and ground glass opacity in the phalanges
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The skull (Figure 10) showed mild basal sclerosis, non-pneumatization of frontal sinuses and partial obliteration of maxillary sinus.
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Figure 10 Lateral skull radiograph demonstrating mild basal sclerosis, non-pneumatization of the frontal sinus, and partial obliteration of the maxillary sinus
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Chest radiographs (Figure 11) revealed widening of the medial third of both clavicles and the ribs also appeared widened with loss of corticomedullary differentiation and thinning of cortex.
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Figure 11 Chest radiograph demonstrating widening of the medial third of both clavicles and ribs, loss of corticomedullary differentiation, and thinning of cortices
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Literature was reviewed and it was found that these features coincided well with those of a rare skeletal dysplasia – metaphyseal dysplasia or Pyle's disease.
The patient was informed about her condition and later referred for endodontic treatment in relation to the mandibular right first permanent molar and left second permanent molar, oral prophylaxis and an opinion from the orthodontist.
Her siblings were examined and subjected to a general skeletal survey; however none of them revealed any abnormal skeletal changes.
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Discussion
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Pyle's disease (PD) is a rare skeletal dysplasia in which a defect in metaphyseal remodelling leads to grossly widened metaphysis of long bones.1 First described by Pyle in 1931,2 so far more than 20 cases have been recognized.3 Familial incidence has been reported by Bakwin and Krida in 19374 and Hermal et al in 1953.5
In 1970, Gorlin described craniometaphyseal dysplasia as a distinct entity, separate from metaphyseal dysplasia.6 Craniometaphyseal dysplasia is a more severe disorder characterized by abnormal craniofacial features with cranial nerve involvement, infrequent hemiplegia or quadriplegia, and mental or motor retardation.6 Synonyms of metaphyseal dysplasia include Pyle's disease and familial metaphyseal dysplasia.
Heselson et al in 1979 described the radiological features of three adults with PD and noted the unremarkable facial features contrasting with the striking radiological features.7 The latter included thinning of the bone cortices in areas of bony expansion. They mentioned that radiographic recognition of PD is not difficult, as the characteristic gross remodelling defects of the long bones are not seen in any other condition. While the Erlenmeyer flask deformity in PD has attracted the attention of many authors, this radiographic feature may also be a manifestation of other disorders such as osteoporosis, prolonged lead poisoning, Gaucher's disease, severe thalassaemia and cartilage dysplasias such as Ollier's disease and diaphyseal actasis. However, those conditions have distinctive clinical features and other characteristic radiological findings of their own.7
Shibuya et al described metaphyseal dysplasia in two families with the involvement of both flat and long bones. They also performed a quantitative measurement of the bone mineral content and reported a marked reduction of the value (one quarter of the normal).8
Clinical signs and symptoms of PD are mild and the disease course is usually benign.3 Occasional abnormalities include muscle weakness, joint pain, scoliosis, platyspondylia, fractures, carious and misplaced teeth, prognathism and enlarged big toe.3 Increased bone fragility is a well recognized but variable component of Pyle disease.7 The lower extremity is more markedly affected than the upper.9
Apart from the history of fracture of her lower right leg, the history and clinical features of the above described case were unremarkable.
Mandibular prognathism, although reported by a few authors,6,7 was not obvious in our patient. Carious and misplaced teeth, which were present in our patient, have been mentioned in several reports.4,7 A review of the literature failed to yield previously reported cases presenting with multiple retained deciduous and missing permanent teeth.
On radiological investigation of our patient, generalized rarefaction of jaws, thinning of cortices and flattening of condyles and several impacted permanent teeth were noted. The general skeletal survey provided further evidence for the bony abnormality with widening of metaphysis, thinning of cortices and Erlenmeyer flask deformity. All these features are consistent with the reported cases of Pyle's disease.
Concerns about the ability to withstand trauma to jaw bones and the nature of healing in patients with this disease will naturally arise. The pathophysiology is incompletely understood, but is apparently due to failure of subperiosteal remodelling in the metaphyses; the cause of this is thought to be chronic hyperaemia of the perichondral ring of osteoblasts. The hyperaemia may be due to congenital hyperplasia of the perichondral ring arteries.9
Bone softness and fragility are well documented in Pyle's disease, which may have surgical implications.7,8 However, Lindberg and Watts performed osteotomy of the left and right proximal tibia in a 15-year-old boy with Pyle's disease. The results of the surgical procedures showed that the post-operative course was similar to that of patients without this disease.1
Extractions and surgeries may have a favourable outcome in patients with Pyle's disease. Minimum force should be used during dental procedures since bone mineral density may be reduced in these patients. However, a close follow-up of a larger group of patients is warranted.
A rare case of Pyle's disease with the dental radiological and clinical findings has been reported. As to whether retained deciduous teeth and missing permanent teeth are coincidental findings or consistent features of Pyle's disease requires observation of other cases with similar disease. Documentation and a detailed study of a larger number of such cases may help in establishing their consistent orofacial features. Pyle's disease should be considered as a rarer cause of generalized rarefaction of the jaws.
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References
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- Lindberg EJ, Watts HG. Postosteotomy healing in Pyle's disease (familial metaphyseal dysplasia) – A case report. Clin Orthop Related Res 1997; 341: 215–217.
- Pyle E. A case of unusual bone development. J Bone Jt Surg Am 1931; 13: 874–876.[Free Full Text]
- Jones KL (editor). Smith's recognizable patterns of human malformation. Philadelphia: W.B. Saunders, 1997: p. 398.
- Bakwin H, Krida A. Familial metaphyseal dysplasia. Am J Dis Child 1937; 53: 1521–1527.
- Hermel MB, Gershon-Cohen J, Jones DT. Familial metaphyseal dysplasia. Am J Roentgenol Radium Ther Nucl Med 1953; 70: 413–421.[Medline]
- Gorlin RJ, Koszalka MF, Spranger J. Pyle's disease (familial metaphyseal dysplasia). A presentation of two cases and argument for its separation from craniometaphyseal dysplasia. J Bone Jt Surg Am 1970; 52: 347–354.[Abstract/Free Full Text]
- Heselson NG, Raad MS, Hamersma H, Cremin BJ, Beighton P. The radiological manifestations of metaphyseal dysplasia (Pyle disease). Br J Radiol 1979; 52: 431–440.[Abstract]
- Shibuya H, Suzuki S, Okuyama T, Yubawa Y. The radiological appearances of familial metaphyseal dysplasia. Clin Radiol 1982; 33: 439–444.[CrossRef][Medline]
- Yochum TR, Rowe LJ (eds). Essentials of skeletal radiology, Second edition. Baltimore: Williams and Wilkins, 1996: pp. 609–610.
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Abstract
Case report
