= “JUVENILE PAGET DISEASE”

= rare autosomal recessive disease with sustained elevation of serum alkaline phosphatase, especially in individuals of Puerto Rican descent

Histo: rapid turnover of lamellar bone without formation of cortical bone; immature woven bone is rapidly laid down, but simultaneous rapid destruction prevents normal maturation

Age: 1^st–3^rd year; usually stillborn

• rapid enlargement of calvarium + long bones; dwarfism
• cranial nerve deficit (blind, deaf); hypertension
• frequent respiratory infections; pseudoxanthoma elasticum
• elevated alkaline phosphatase
• deossification = decreased density of long bones with coarse trabecular pattern
• metaphyseal growth deficiency
• wide irregular epiphyseal lines (resembling rickets in childhood), persistent metaphyseal defects (40% of adults)
• bowing of long bones + fractures with irregular callus
• widened medullary canal with cortical thinning (cortex modeled from trabecular bone)
• skull greatly thickened with wide tables, cotton wool appearance
• vertebra plana

OB-US:

• diagnosis suspected in utero in 20%

Cx: pathologic fractures; vertebra plana universalis

DDx:

1. Osteogenesis imperfecta
2. Polyostotic fibrous dysplasia
3. Paget disease (>age 20, not generalized)
4. Pyle disease (spares midshaft)
5. van Buchem syndrome (only diaphyses >age 20, no long-bone bowing)
6. Engelmann syndrome (lower limbs)