QUIZ: No. 50, Dec 29

Answer: Paget`s disease of skull with Giant cell tumor

Paget`s disease of skull shows imaging findings based on lytic (osteoporosis circumscripta) mixed or sclerotic phase (osteosclerosis, coarsening of trabeculae, cortical thickening & bone expansion). Skull lesions are prominent in the inner calvarial tables & usually cross the suture lines.

Neoplasms complicating pagetic bone are sarcomatous degeneration, giant cel tumor or superimposed metastases, myeloma or lymphoma. GCT of pagetic bone is rare & occurs in the skull, facial bones, pelvis, clavicle, spine & tubular bones. These patients are generally elderly persons with polyostotic involvement. MR images show osseous lesion with variable signal characteristic of pagetic bone & a soft tissue mass of intermediate T1 signal & focal high T2 signal. Cystic & hemorrhagic regions may be present.