"Genetics "
"osteoporosis circumscripta: large, well-defined lytic lesions involving the inner aspect of the outer table of the skull (stage one) with a preserved inner table."
"cotton wool appearance: mixed lytic and sclerotic lesions of the skull."
"Paget disease of the bone is the most common formal name for the condition 18. Synonymous terms such as osteitis deformans, which was the name Paget himself gave to the disease, are of historical interest only."
"blade of grass or candle flame sign: begins as a subchondral area of lucency with an advancing tip of V-shaped osteolysis, extending towards the diaphysis"
"Current estimates suggest a prevalence of ~5% (range 1.5-8.3%) globally, with most populations showing rates of 1-2% in adults over 55 years. Historical studies from the UK in the 1970s-1980s reported prevalence up to 4% in individuals over 40 years and up to 8-11% in those over 80 years 1, but contemporary data demonstrate substantially lower rates, suggesting changes in environmental exposures or other factors 3,22."
"The aetiology is not entirely established, but environmental exposures, such as viral infection (paramyxovirus) 3,22, in association with a genetic susceptibility (e.g. SQSTM1) 23, have been postulated."
"The most common mutation affects the sequestosome 1 gene (SQSTM1) and has been described in approximately 25-40% of familial cases and in up to 10-15% of sporadic cases 23-25. Disease develops at an earlier age and is more severe in these individuals 23. Mutations in the VCP gene predispose to Paget disease, inclusion body myositis, and frontotemporal dementia, which can co-occur 33."
"Looser zones"
"Modic type 2 endplate change"
Expected headings
"Genetics "
"Signs"
"Plain radiograph/CT"
"Skull"
"Spine"
"Pelvis"
"Long bones"
"Bone scintigraphy"
"Guidelines"
"Complications"
"There are three classically described stages, which are part of a continuous spectrum that correlate well with imaging findings 16:"
"There are many Paget disease-related signs, listed here and described in the modality-specific sections below 19:"
"Tam o' Shanter sign: platybasia and basilar invagination with the appearance of the skull falling over the facial bones, like a Tam o' Shanter hat; this is said to be a pathognomonic appearance 25"
"dominant signal intensity in Pagetic bone, similar to that of fat; the most common pattern probably corresponds to long-standing disease"
"relatively low T1 and high T2 signal alteration (also referred to as a “speckled” appearance); second most common pattern: probably corresponds to granulation tissue, hypervascularity, and oedema seen in early mixed active disease"
"low signal intensity on both T1 and T2 images, suggesting the presence of compact bone or fibrous tissue; least common pattern: seen in late sclerotic stage"
"Mickey Mouse sign: uptake in the vertebral body and posterior elements forming an inverted triangular pattern on posterior planar imaging, resembling the Mickey Mouse silhouette 11,12; also known as the "heart" or "clover" sign 13 and "T" or "champagne glass" sign 14"