Paget's Disease of Bone in Patients under 40 Years: Two case reports and review of the literature.

Paget's disease of bone (PDB) is a focal disorder of accelerated skeletal remodelling that is uncommon in patients under the age of 40 years; it is more prevalent in older individuals. We report two cases of PDB diagnosed in early adulthood at the Mohamed Kassab Institute of Orthopedics, La Manouba, Tunisia. The first case was a 35-year-old male patient who presented in 2011 with a seven-month history of hip pain. The second case was a 39-year-old female patient who presented 2014 with chronic lower back pain. The PDB diagnosis was confirmed with clinical, biological and radiological investigations. Both patients were doing well on follow-up. Some previous cases have been reported in the literature, differing from the presented cases in some aspects; data of PDB features at differing ages is still insufficient. Early recognition of this clinical entity in young patients is important as early treatment can affect the progression of the disease.