The phrase "mosaic pattern" of newly formed woven bone is a specific tip-off for Paget's disease of bone, and is not seen in other bone conditions. The clinical and radiologic presentation are typical; an increased hat size may also be a clue. In its early stages, Paget's disease is characterised by osteolysis, producing patchwork areas of bone resorption with bizarre, large osteoclasts. In the middle stage of the disease, secondary osteoblastic activity compensates with new bone formation, producing the mosaic pattern. In late Paget's, the bones are dense and osteosclerotic. Paget's disease is suspected to be related to prior viral infection, but the cause remains mysterious. Complications include myelophthisic anemia, high output cardiac failure, pain secondary to nerve compression, deformities secondary to skeletal changes, and in about 1% of patients, osteosarcoma or other sarcoma, typically involving the jaw, pelvis, or femur. An increased incidence of astrocytomas is associated with tuberous sclerosis.Hodgkin's lymphoma is usually a disease of young adults, although older patients may have the lymphocyte-depleted form.Meningiomas are mostly benign tumors that affect adults, especially females. There may be an association with breast cancer, possibly related to high estrogen states. Ref: Wyatt C., Butterwoh IV J.F., Moos P.J., Mackey D.C., Brown T.G. (2008). Chapter 19. Pathology of the Bones and Joints. In C. Wyatt, J.F. Butterwoh IV, P.J. Moos, D.C. Mackey, T.G. Brown (Eds), Pathology: The Big Picture.