Etiology • Unknown, although several theories exist including the following:
• Inborn error of connective tissue metabolism • Paramyxovirus or slow virus infection • Autoimmune-mediated vascular disorder • Possible association with alterations involving chromosomes
6 and 18 • Familial form exists
Clinical Presentation • Nearly one-fifth of cases involve the mandible and maxilla. • Maxillary and mandibular involvement is usually bilateral and
symmetric. • Maxilla predominates over mandible by 2:1 • Jaw and skull enlargement common • Often deep aching pain in affected bone(s) • Neurologic complications, as follows, in later phases of uncon-
• Inborn error of connective tissue metabolism • Paramyxovirus or slow virus infection • Autoimmune-mediated vascular disorder • Possible association with alterations involving chromosomes
6 and 18 • Familial form exists
Clinical Presentation • Nearly one-fifth of cases involve the mandible and maxilla. • Maxillary and mandibular involvement is usually bilateral and
symmetric. • Maxilla predominates over mandible by 2:1 • Jaw and skull enlargement common • Often deep aching pain in affected bone(s) • Neurologic complications, as follows, in later phases of uncon-
trolled or advanced cases: • Vertigo, headache • Auditory/visual disturbances • Facial paresis
• Monostotic involvement occurs but rarely • Dental patients often complain of ill-fitting prostheses or slow
separation of teeth.
Radiographic Findings • Initially ill-defined, often multiple lytic lesions noted • Later stage shows patchy radiopaque pattern (like cotton
wool) • Hypercementosis recognizable by “drumstick” appearance of
root outline • Lamina dura–periodontal membrane space may become
obliterated.
Laboratory Findings • Increased serum alkaline phosphatase • Serum calcium and phosphate normal • Elevated urinary calcium and hydroxyproline levels
Microscopic Findings • Early phase predominantly has osteoclastic resorption, fibrous
tissue replacement of bone, and prominent blood vessels • Late phase (sclerotic) has predominantly osteoblastic function,
which results in dense bone with numerous reversal lines
Diagnosis • Radionuclide imaging to determine extent and distribution of
lesions
Differential Diagnosis • Osteosarcoma • Fibrous dysplasia • Acromegaly
Treatment • Bisphosphonate therapy • Calcitonin • Pain control
Prognosis and Complications • Slowly progressive • Deformities and neurologic complications in late phases • Malignant transformation may occur (osteosarcoma) in 1% of
cases, secondary to loss of heterozygosity in chromosome 18q.